WO2024176179A1

WO2024176179A1 - Patient interface

Info

Publication number: WO2024176179A1
Application number: PCT/IB2024/051744
Authority: WO
Inventors: Andre VAN SCHALKWYK; Samuel Carey Mathew SANSON; David Robin Whiting; Samuel Robertson Frame; Stanislav Tatkov
Original assignee: Fisher & Paykel Healthcare Limited
Priority date: 2023-02-24
Filing date: 2024-02-23
Publication date: 2024-08-29
Also published as: TW202448540A; CN118543007A; AU2024226652A1; CN222899927U

Abstract

A nasal interface (100) for delivering a flow of gases to a patient. The nasal interface (100) has a first prong (111), a second prong (112) and a gases manifold (120). The nasal interface (100) is configured to cause an asymmetrical flow at a patient's nares. At least one of the first prong (111), second prong (112) or gases manifold (120) comprises an element positioned to increase a resistance to flow of a flow of gases travelling therethrough and thus to at least one of the prongs (111, 112).

Description

PATIENT INTERFACE

[0001] This application claims priority from United States Provisional Application No. 63/486,795 filed on 24 February 2023, and entitled 'Patient Interface', the entire of contents of which are hereby incorporated by reference.

FIELD

[0002] The present disclosure generally relates to a patient interface for delivering breathing gases to airways of a patient.

BACKGROUND

[0003] Humidifiers are used to provide humidified respiratory gases to a patient. Gases are delivered to the patient via a patient interface. Examples of a patient interface include an oral mask, a nasal mask, a nasal cannula, a combination of oral and nasal mask, and the like.

[0004] Patient interfaces comprising nasal interfaces can be used to deliver a high flow of gases to a patient. Nasal delivery prongs or elements are inserted into the nose of a patient to deliver the required therapy. The nasal delivery prongs may be required to seal or semi-seal at the nose, or may not be required to seal at the nose, to deliver the therapy. Nasal high flow typically is a non-sealing therapy that delivers relatively high- volume flow to the patient through a nasal interface, which flow may be sufficient to meet or exceed the patient's inspiratory flow rate.

SUMMARY

[0005] Disclosed herein is a nasal interface with features that allow the nasal interface to provide an asymmetrical flow to a patient. The nasal interface may be configured to deliver nasal high flow. An asymmetrical flow can provide the patient with increased dead space clearance in the upper airways. One or more features of the nasal interface disclosed herein that allow the nasal interface to achieve an asymmetrical flow at the patient's nares can reduce the (overall) resistance to flow through the nasal interface, which can achieve desired flow rates using lower backpressure and/or lower motor speeds of the flow generating device.

[0006] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold comprising a manifold chamber and a gases inlet; and at least one element positioned within the first prong, second prong or manifold chamber, wherein the at least one element is configured to increase a resistance to a flow of gases travelling through at least one of the first prong, second prong, or manifold chamber and wherein the gases inlet is, or is configured to be, in fluid communication with a gases-conveying conduit.

[0007] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold comprising a manifold chamber and a gases inlet; and a second prong element positioned within the second prong, wherein the second prong element is configured to increase a resistance to flow of a flow of gases travelling through second prong, and wherein the gases inlet is, or is configured, to be in fluid communication with a gases-conveying conduit.

[0008] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold comprising a manifold chamber and a gases inlet; and a manifold element positioned within the manifold chamber, wherein the manifold element is configured to increase a resistance to a flow of gases travelling through manifold chamber and to at least one of the first prong or second prong, and wherein the gases inlet is, or is configured to be, in fluid communication with a gases-conveying conduit.

[0009] In some configurations, the increase in resistance to the flow of gases is configured to cause an asymmetrical flow of gases at the first prong and the second prong. [0010] In some configurations, the first prong, second prong, manifold chamber and gases inlet are in fluid communication with one another.

[0011] In some configurations, the at least one element is a second prong element positioned within the second prong.

[0012] In some configurations, the second prong element is configured to increase a resistance to the flow of gases travelling through the second prong.

[0013] In some configurations, the second prong element is positioned at the second base.

[0014] In some configurations, the base of the second prong comprises an entrance to a flow passage formed by a wall of the second prong.

[0015] In some configurations, the nasal interface comprises a manifold element, wherein the manifold element is positioned within the manifold chamber of the gases manifold.

[0016] In some configurations, the manifold element is configured to increase a resistance to flow to the flow of gases travelling through the manifold chamber.

[0017] In some configurations, the flow of gases is substantially in a direction from the gases manifold inlet, through the gases manifold chamber, and into a flow passage of the first prong and/or the second prong. [0018] In some configurations, the manifold element is positioned substantially in the centre of the manifold chamber.

[0019] In some configurations, the nasal interface comprises a first prong element, wherein the first prong element is positioned within the first prong.

[0020] In some configurations, the first prong element is configured to increase the resistance to flow of a flow of gases travelling through the first prong.

[0021] In some configurations, the first prong element is positioned at the base of the first prong.

[0022] In some configurations, the first prong element provides a different resistance to a flow of gases than the second prong element.

[0023] In some configurations, the gases conveying conduit is between a patient conduit and the gases inlet.

[0024] In some configurations, the gases manifold is integrally formed with the gases conveying conduit or is coupled to the gases conveying conduit.

[0025] In some configurations, the gases manifold comprises a manifold width, and wherein the manifold width is as large as or larger than an inner diameter of at least one of the first prong or second prong.

[0026] In some configurations, the nasal interface comprises a cannula body comprising the first prong and the second prong, and wherein an external surface of the cannula body between the first prong and the second prong comprises a dip to accommodate a portion of a patient's nose and reduce pressure on an underside of the accommodated portion.

[0027] In some configurations, at least one of the first prong or second prong is sized to maintain a sufficient gap between the outer surface of the at least one prong and a patient's skin to avoid sealing a gas path between the nasal interface and the patient.

[0028] In some configurations, at least the first prong or second prong is made of an elastomeric material that enables the first prong to deform and set its shape in use in response to temperature and contact with the patient's naris.

[0029] In some configurations, at least one of the first prong or second prong is not made of silicone.

[0030] In some configurations, at least one of the first prong or second prong is made of a thermoplastic elastomer.

[0031] In some configurations, the nasal interface is configured to cause an asymmetrical flow of gases at a patient's nares.

[0032] In some configurations, the gases manifold comprises a flow channel that has a gases flow direction that is substantially perpendicular to gases flow paths through the first prong and the second prong. [0033] In some configurations, the manifold element comprises a manifold aperture for the passage of a gases flow, wherein said manifold aperture has a smaller cross- sectional opening than the manifold chamber for the gases flow.

[0034] In some configurations, the second prong comprises a second aperture for the passage of a gases flow, wherein said second aperture has a smaller cross-sectional opening than the second prong for the gases flow.

[0035] In some configurations, the manifold aperture and/or second aperture is formed in a plate or a wall.

[0036] In some configurations, the plate or wall has an inlet surface and an outlet surface with the manifold aperture and/or second manifold formed therebetween.

[0037] In some configurations, a gases flow is in the direction from the inlet surface to the outlet surface through the manifold aperture and/or second aperture.

[0038] In some configurations, the transition between the outlet surface and the manifold aperture and/or second aperture is tapered.

[0039] In some configurations, the transition between the inlet surface and the manifold aperture and/or second aperture is substantially right angled.

[0040] In some configurations, the transition between the inlet surface and the manifold aperture and/or second aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

[0041] In some configurations, the transition between the inlet surface and the manifold aperture and/or second aperture is substantially a sharp corner.

[0042] In some configurations, the at least one manifold aperture and/or second aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

[0043] In some configurations, the at least one manifold aperture and/or second aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall.

[0044] In some configurations, the at least one manifold aperture and/or second aperture is a substantially circular perforation.

[0045] In some configurations, the at least one manifold aperture and/or second aperture comprises a pattern of perforations.

[0046] In some configurations, the plate or wall of the at least one manifold aperture and/or second aperture comprises a porous medium.

[0047] In some configurations, any one or more of the second prong element and/or, the manifold element and/or first prong element comprises a valve.

[0048] In some configurations, the valve is configured to open only at a threshold pressure or flow rate.

[0049] In some configurations, the valve is configured to provide a defined pressure drop in the flow path.

[0050] In some configurations, the valve is a duckbill valve. [0051] In some configurations, any one or more of the second prong element and/or, the manifold element and/or first prong element comprises a nozzle.

[0052] In some configurations, the nozzle is configured to provide a defined pressure drop in the flow path.

[0053] In some configurations, the manifold element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

[0054] In some configurations, the manifold element is configured to be slidably movable in an upstream-downstream direction.

[0055] In some configurations, wherein the manifold element comprises a rotatable piece with a helical thread.

[0056] In some configurations, the manifold element further comprises a portion external to the gases manifold of the nasal interface.

[0057] In some configurations, the manifold element is configured to be rotatably movable, such that when the external portion is rotated, the manifold element translates vertically into or out the manifold chamber flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

[0058] In some configurations, the gases manifold comprises an opening at a wall approximately opposite the gases inlet of the manifold and/or approximately opposite the second base of the second prong.

[0059] In some configurations, the opening comprises one or a plurality of apertures.

[0060] In some configurations, wherein the number and diameter of said apertures are configured to provide a defined pressure drop.

[0061] In some configurations, the opening in the wall of the manifold is pneumatically connected to a component configured to provide a defined pressure drop [0062] In some configurations, the component is at least one of a porous medium, a nozzle, a pressure-relief valve or a bubble CPAP bubbling chamber.

[0063] In some configurations, an axis of the gases inlet is co-axial relative to an axis of at least one of the first prong or second prong.

[0064] In some configurations, the angle of the axis of the gases inlet is perpendicular relative to the axis of at least one of the first prong or second prong.

[0065] In some configurations, the nasal interface comprises an auxiliary gases inlet to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[0066] In some configurations, the auxiliary gases inlet terminates in the first prong or the second prong.

[0067] In some configurations, the auxiliary gases conduit comprises an inlet and terminates at the inlet in the first prong or the second prong. [0068] In some configurations, the auxiliary gases inlet is in fluid communication with an auxiliary gases conveying conduit.

[0069] In some configurations, at least one of the gases inlet or gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the auxiliary gases inlet or auxiliary gases conveying conduit comprises a lumen with a second internal cross-sectional area.

[0070] In some configurations, one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

[0071] In some configurations, the first internal cross-sectional area and the second internal cross-sectional area are different.

[0072] In some configurations, the second internal cross-sectional area is smaller than an internal cross-sectional area of the first prong or second prong.

[0073] In some configurations, the gases conveying conduit and the auxiliary gases conveying conduit are disposed on the same side of the manifold chamber.

[0074] In some configurations, the auxiliary gases conveying conduit is positioned in the gases conveying conduit.

[0075] In some configurations, at least one of the gases inlet or the gases conveying conduit comprises a first length and at least one of the auxiliary gases inlet or the auxiliary gases conveying conduit comprises a second length.

[0076] In some configurations, the first length and the second length are unequal to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[0077] In some configurations, the first length is longer than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[0078] In some configurations, the first length is shorter than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[0079] In some configurations, the gases-conveying conduit is in communication with a first gases flow and the auxiliary gases conveying conduit is in communication with a second gases flow.

[0080] In some configurations, the first gases flow has a different flow rate to the second gases flow.

[0081] In some configurations, a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

[0082] In some configurations, one of the first or second gases flow is a suction flow. [0083] In some configurations, a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

[0084] In some configurations, a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

[0085] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; and a gases manifold comprising: a manifold chamber; a first gases inlet; and a second gases inlet, wherein the first gases inlet and the second gases inlet are disposed on opposite ends of the manifold chamber and are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively.

[0086] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; and a gases manifold comprising: a manifold chamber; a first gases inlet; a second gases inlet, wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, wherein the nasal interface is configured to cause the asymmetrical flow of gases at the first prong and the second prong.

[0087] In some configurations, the first gases inlet and the second gases inlet are disposed on opposite sides of the manifold chamber.

[0088] In some configurations, the first gases inlet is more proximal to the first prong than the second inlet and wherein the second inlet is more proximal to the second prong than the first inlet.

[0089] In some configurations, at least one of the first gases inlet and first gases conveying conduit formed as a unitary structure or the second gases inlet and second gases conveying conduit are formed as a unitary structure.

[0090] In some configurations, the first gases conveying conduit is in communication with a first gases flow and the second gases conveying conduit is in communication with a second gases flow.

[0091] In some configurations, the first gases flow has a different flow rate to the second gases flow.

[0092] In some configurations, a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

[0093] In some configurations, one of the first or second gases flow is a suction flow.

[0094] In some configurations, a gas pressure of the first gases flow is different to a gas pressure of the second gases flow. [0095] In some configurations, a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

[0096] In some configurations, the first prong, second prong, manifold chamber, first gases inlet and second gases inlet are in fluid communication with one another [0097] In some configurations, the nasal interface comprises a flow-altering feature configured to cause an asymmetrical flow of gases at the first prong and the second prong. [0098] In some configurations, wherein the first inlet and/or first gases conveying conduit comprises a lumen with a first internal cross-sectional area and the second inlet and/or second gases conveying conduit comprises a lumen with a second internal cross- sectional area to cause the asymmetrical flow of gases at the first prong and the second prong.

[0099] In some configurations, the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

[00100] In some configurations, the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially non-circular.

[00101] In some configurations, the first internal cross-sectional area and the second internal cross-sectional area are unequal to cause the asymmetrical flow of gases at the first prong and the second prong.

[00102] In some configurations, the first internal cross-sectional area is larger than the second internal cross-sectional area to cause the asymmetrical flow of gases at the first prong and the second prong.

[00103] In some configurations, the first internal cross-sectional area is smaller than the second internal cross-sectional area to cause the asymmetrical flow of gases at the first prong and the second prong.

[00104] In some configurations, the first inlet and/or first gases conveying conduit comprises a first length and the second inlet and/or second gases conveying conduit comprises a second length to cause the asymmetrical flow of gases at the first prong and the second prong.

[00105] In some configurations, the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong.

[00106] In some configurations, the first length is longer than the second length to cause the asymmetrical flow of gases at the first prong and the second prong.

[00107] In some configurations, the first length is shorter than the second length to cause the asymmetrical flow of gases at the first prong and the second prong.

[00108] In some configurations, the internal surface of the first inlet and/or the first gases conveying conduit comprises a first pattern of relief features.

[00109] In some configurations, the internal surface of the second inlet and/or the second gases conveying conduit comprises a second pattern of relief features. [00110] In some configurations, the first pattern of relief features is substantially rougher than the second pattern of relief features to cause the asymmetrical flow of gases at the first prong and the second prong.

[00111] In some configurations, wherein the first pattern of relief features is substantially smoother than the second pattern of relief features to cause the asymmetrical flow of gases at the first prong and the second prong.

[00112] In some configurations, the pattern of relief features comprises one or more of: dimples, protrusions, ribs, and/or fins.

[00113] In some configurations, an axis of the one or both of the first gases inlet and second gases inlet is co-axial relative to an axis of at least one of the first prong or second prong.

[00114] In some configurations, the angle of the axis of the first gases inlet and/or second gases inlet is perpendicular relative to the axis of at least one of the first prong or second prong.

[00115] In some configurations, the nasal interface comprises at least one of: (i) a first prong element positioned within the first prong; (ii) a second prong element positioned within the second prong; (iii) a manifold element positioned in the manifold chamber and between the first base of the first prong and the second base of the second prong; (iv) a first gases inlet element positioned at the first gases inlet to the gases manifold; or (v) a second gases inlet element positioned at the second gases inlet to the gases manifold, wherein the first prong element, second prong element, manifold element, first gases inlet element and/or second gases inlet element are each configured to increase the resistance to flow of a flow of gases entering said respective element to cause the asymmetrical flow of gases at the first prong and the second prong.

[00116] In some configurations, the nasal interface comprises the first gases inlet element and the second gases inlet element each configured to increase the resistance to flow of a flow of gases entering the manifold through the first gases inlet and second gases inlet respectively.

[00117] In some configurations, the nasal interface comprises the first prong element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the first prong and second prong respectively.

[00118] In some configurations, the nasal interface comprises the manifold element and the first gases inlet element each configured to increase the resistance to flow to a flow of gases within the manifold chamber and entering the manifold through the manifold element and first gases inlet element respectively.

[00119] In some configurations, the nasal interface comprises the manifold element and the second gases inlet element each configured to increase the resistance to flow to a flow of gases within the manifold chamber and entering the manifold through manifold element and the second gases inlet element respectively. [00120] In some configurations, at least one of the first prong element, the second prong element, the manifold element, the first gases inlet element or the second gases inlet element comprises an aperture for a reduced passage of a gases flow.

[00121] In some configurations, wherein said aperture has a smaller cross-sectional opening than at least one of the flow channels for first prong, second prong or manifold chamber, or the first lumen or second lumen for the gases flow.

[00122] In some configurations, the aperture is formed in a plate or a wall.

[00123] In some configurations, the plate or wall has an inlet surface and an outlet surface with the aperture formed therebetween.

[00124] In some configurations, a gases flow is in the direction from the inlet surface to the outlet surface through the aperture.

[00125] In some configurations, the transition between the outlet surface and the aperture is tapered.

[00126] In some configurations the transition between the inlet surface and the aperture is substantially right angled.

[00127] In some configurations the transition between the inlet surface and the aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

[00128] In some configurations the transition between the inlet surface and the aperture is substantially a sharp corner.

[00129] In some configurations the at least one aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

[00130] In some configurations the at least one aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall.

[00131] In some configurations the at least one aperture is a substantially circular perforation.

[00132] In some configurations the at least one aperture comprises a pattern of perforations.

[00133] In some configurations the plate or wall of the at least one aperture comprises a porous medium.

[00134] In some configurations, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element comprises a valve.

[00135] In some configurations, the valve is configured to open only at a threshold pressure or flow rate.

[00136] In some configurations, the valve is configured to provide a defined pressure drop in the flow path.

[00137] In some configurations, the valve is a duckbill valve. [00138] In some configurations, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element comprises a nozzle.

[00139] In some configurations, the nozzle is configured to provide a defined pressure drop in the flow path.

[00140] In some configurations, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

[00141] In some configurations, the element is configured to be slidably movable in an upstream-downstream direction.

[00142] In some configurations, the element comprises a rotatable piece with a helical thread.

[00143] In some configurations, the element further comprises a portion external to the nasal interface.

[00144] In some configurations, the element is configured to be rotatably movable, such that when the external portion is rotated, the element translates vertically into or out the flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

[00145] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong and a second prong; a gases manifold comprising a manifold chamber and a gases inlet, the gases inlet is, or is configured to be, in fluid communication with a gases- conveying conduit; and at least one flow-directing element, wherein the at least one flowdirecting element is configured to direct a flow of gases from the gases inlet to one of the first prong or second prong to create an asymmetric flow of gases.

[00146] In some configurations, the at least one flow-directing element is the gases inlet.

[00147] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong and a second prong; a gases manifold comprising a manifold chamber and a gases inlet, the gases inlet is, or is configured to be, in fluid communication with a gases- conveying conduit; and at least one flow-directing element formed as part of at least one of the manifold chamber, gases inlet or gases-conveying conduit, wherein the at least one flow-directing element is configured to direct a flow of gases to one of the first prong or second prong to create an asymmetric flow of gases.

[00148] In some configurations, the first prong, second prong, manifold chamber and first gases inlet are in fluid communication with one another [00149] In some configurations, the flow directing element is configured to provide a larger dynamic pressure at the first prong in use and to provide a smaller dynamic pressure at the second prong in use, to create the asymmetric flow of gases.

[00150] In some configurations, at least one of the first prong or second prong is sized to maintain a sufficient gap between the outer surface of the at least one prong and a patient's skin to avoid sealing a gas path between the nasal interface and the patient.

[00151] In some configurations, the first prong and second prong are in fluid communication with the manifold chamber.

[00152] In some configurations, the gases inlet is positioned in the manifold chamber opposite at least one of the first prong or second prong.

[00153] In some configurations, the at least one flow-directing element is positioned within the gases manifold chamber.

[00154] In some configurations, the at least one flow-directing element is positioned within the gases-conveying conduit.

[00155] In some configurations, the at least one flow-directing element is positioned within the gases-conveying conduit, where the gases-conveying conduit meets the gases inlet.

[00156] In some configurations, the at least one flow-directing element comprises at least one angled protrusion, wherein the protrusion is configured to direct a flow of gases towards one of the first prong or second prong from the gases inlet.

[00157] In some configurations, the at least one flow-directing element further comprises a second angled protrusion, positioned opposite the first protrusion in the flow path and configured likewise to direct a flow of gases towards one of the first prong or second prong from the gases inlet.

[00158] In some configurations, the nasal interface comprises a second flowdirecting element, positioned at the entrance to one of the first prong or second prong in the gases manifold.

[00159] In some configurations, the second flow-directing element is configured to direct a flow of gases towards one of the first prong or second prong from the gases inlet. [00160] In some configurations, the second flow-directing element is configured to direct a flow of exhalation gases from the first prong or second prong to the opposing prong.

[00161] In some configurations, the second flow-directing element comprises at least one angled protrusion, wherein the protrusion is configured to direct a flow of gases of gases towards one of the first prong or second prong from the gases inlet, and is configured to direct a flow of exhalation gases from the first prong or second prong to the opposing prong.

[00162] In some configurations, an axis of the gases inlet is co-axial relative to an axis of at least one of the first prong or second prong. [00163] In some configurations, the angle of the axis of the gases inlet is perpendicular relative to the axis of at least one of the first prong or second prong.

[00164] In some configurations, the gases inlet is positioned in the manifold chamber at a position substantially centrally between the first prong and the second prong.

[00165] In some configurations, the at least one flow-directing element is positioned within the gases manifold chamber and is proximal to the first prong.

[00166] In some configurations, the at least one flow-directing element is configured to direct the gases flow from the gases-conveying conduit towards the entrance of the first prong.

[00167] In some configurations, the second flow-directing element is configured to direct the gases flow from the entrance of the first prong into a first prong flow passage. [00168] In some configurations, the at least one flow-directing element is positioned within the gases manifold chamber and is proximal to the second prong.

[00169] In some configurations, the at least one flow-directing element is configured to direct the gases flow from the gases-conveying conduit towards the entrance of the second prong.

[00170] In some configurations, the second flow-directing element is configured to direct the gases flow from the entrance of the second prong into a second prong flow passage.

[00171] In some configurations, the nasal interface comprises at least one of: (i) a first prong element positioned within the first prong; (ii) a second prong element positioned within the second prong; (iii) a manifold element positioned in the manifold chamber and between the first base of the first prong and the second base of the second prong; wherein the first prong element, second prong element and/or manifold element are each configured to increase the resistance to flow of a flow of gases entering said respective element.

[00172] In some configurations, the nasal interface comprises the first prong element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the first prong and second prong respectively.

[00173] In some configurations, the nasal interface comprises the manifold element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the prong and within the manifold chamber through the second prong element and manifold element respectively.

[00174] In some configurations, at least one of the first prong element, the second prong element and/or the manifold element comprises an aperture for a reduced passage of a gases flow.

[00175] In some configurations, the aperture has a smaller cross-sectional opening than a cross-section of a flow channel for at least one of the first prong, second prong or manifold chamber. [00176] In some configurations, the first prong has a first prong length and the second prong has a second prong length, and wherein the first prong length is different to the second prong length.

[00177] In some configurations, the first prong length is longer than the second prong length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[00178] In some configurations, the first prong length is shorter than the second prong length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[00179] In some configurations, the first prong has a first prong cross-sectional width and the second prong has a second prong cross-sectional width, and wherein the first prong cross-sectional width is different to the second prong cross-sectional width.

[00180] In some configurations, the first prong cross-sectional width is larger than the second prong cross-sectional width to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[00181] In some configurations, the first prong cross-sectional width is smaller than the second prong cross-sectional width to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[00182] In some configurations, the first prong has a first terminal end and the second prong has a second terminal end, and wherein geometries of the first terminal end and second terminal end are different to cause the asymmetrical flow of gases at the first prong and at the second prong.

[00183] In some configurations, at least one of the first terminal end or the second terminal end is narrowed or tapered to form a nozzle shape.

[00184] In some configurations, at least one of the first terminal end or the second terminal end is widened or tapered to form a diffuser shape.

[00185] In some configurations, the first prong has a first internal surface and the second prong has a second internal surface, wherein at least one of the first internal surface or second internal surface has surface features configured to effect internal flow resistances of the at least one first prong or second prong.

[00186] In some configurations, the surface features are ridges formed as rings, spirals or strips in a concentric pattern around the first or second internal surface.

[00187] In some configurations, the surface features are fins formed as lines, strips or bars in a substantially axial directional pattern along the first or second surface.

[00188] In some configurations, when the surface features are present on the first and second internal surface, the surface features are different to cause the asymmetrical flow of gases at the first prong and at the second prong. [00189] In some configurations, at least one of the first prong and second prong is a non-circular cross-sectional shape, the non-circular cross-sectional shape configured to effect internal flow resistances of the at least one first prong or second prong.

[00190] In some configurations, the non-circular cross-sectional shape is reduced by the size of a circular cross-sectional shape removed therefrom.

[00191] In some configurations, the non-circular cross-sectional shape is substantially U-shaped.

[00192] In some configurations, the non-circular cross-sectional shape is substantially polygonal.

[00193] In some configurations, when the non-circular cross-sectional shape is present on each of the first and second prongs, the non-circular cross-sectional shapes are different to cause or contribute to the asymmetrical flow of gases at the first prong and at the second prong.

[00194] In some configurations, at least one of the first prong and second prong comprises a base restriction at a base of the prong, the base restriction configured to effect internal flow resistances of the at least one first prong or second prong.

[00195] In some configurations, the base restriction is a nozzle or a diffuser formed at the base of the prong.

[00196] In some configurations, when the base restriction is present on the first and second prongs, the base restrictions are different to cause or contribute to the asymmetrical flow of gases at the first prong and at the second prong.

[00197] In some configurations, at least one of the first prong and second prong comprises a valve within the prong, the valve configured to effect internal flow resistances of the at least one first prong or second prong.

[00198] In some configurations, the valve is configured to restrict or prevent a gases flow therethrough until the gases flow exceeds a defined pressure.

[00199] In some configurations, the valve is a duckbill valve.

[00200] In some configurations, the valve is a one-way valve.

[00201] In some configurations, the valve is present in each of the first and second prongs, the valves have different characteristics to cause the asymmetrical flow of gases at the first prong and at the second prong.

[00202] In some configurations, the nasal interface further comprises a third prong, wherein the first, second and third prongs are spaced apart to be engageable into the nares of a patient as adjacent pairs, wherein at least one of the first, second or third prongs have different flow characteristics to the other prongs to cause or contribute to the asymmetrical flow of gases at the respective prongs.

[00203] In some configurations, the nasal interface further comprises a closure for releasably preventing a flow of gases through the first, second or third prong. [00204] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold; a first gases inlet; and an auxiliary gases inlet, wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, wherein the nasal interface is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

[00205] In some configurations, the first gases inlet terminates in the gases manifold.

[00206] In some configurations, the auxiliary gases inlet terminates in the first prong or the second prong.

[00207] In some configurations, the auxiliary gases inlet is in fluid communication with an auxiliary gases conveying conduit.

[00208] In some configurations, the at least one of the gases inlet or gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the auxiliary gases inlet or auxiliary gases conveying conduit comprises a lumen with a second internal cross-sectional area.

[00209] In some configurations, the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

[00210] In some configurations, the first internal cross-sectional area and the second internal cross-sectional area are different.

[00211] In some configurations, the second internal cross-sectional area is smaller than an internal cross-sectional area of the first prong or second prong.

[00212] In some configurations, the gases conveying conduit and the auxiliary gases conveying conduit are disposed on the same side of the gases manifold.

[00213] In some configurations, the auxiliary gases conveying conduit is positioned in the gases conveying conduit.

[00214] In some configurations, wherein at least one of the gases inlet or the gases conveying conduit comprises a first length and at least one of the auxiliary gases inlet or the auxiliary gases conveying conduit comprises a second length.

[00215] In some configurations, wherein the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong. [00216] In some configurations, wherein the first length is longer than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

[00217] In some configurations, wherein the first length is shorter than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong. [00218] In some configurations, wherein the gases conveying conduit is in communication with a first gases flow and the auxiliary gases conveying conduit is in communication with a second gases flow.

[00219] In some configurations, wherein the first gases flow has a different flow rate to the second gases flow.

[00220] In some configurations, wherein a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

[00221] In some configurations, wherein one of the first or second gases flow is a suction flow.

[00222] In some configurations, wherein a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

[00223] In some configurations, herein a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

[00224] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a patient interface comprising the nasal interface as herein described.

[00225] In some configurations, the patient interface further comprises a headgear to retain the nasal interface against a patient's face.

[00226] In some configurations, the patient interface further comprises the gases- conveying conduit that is in fluid communication with the gases inlet.

[00227] In some configurations, wherein the gases-conveying conduit is a breathable tube.

[00228] In some configurations, wherein the gases manifold is integrally formed with the gases-conveying conduit or is coupled to the gases-conveying conduit.

[00229] In some configurations, the gases-conveying conduit couples the gases inlet to a patient conduit that provides gases from a flow generator.

[00230] In some configurations, the patient interface further comprises a gases- conveying conduit retention clip.

[00231] In accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a respiratory therapy system comprising: a respiratory therapy apparatus comprising: a controller; a blood oxygen saturation sensor; an ambient air inlet; an oxygen inlet; a valve in fluid communication with the oxygen inlet to control a flow of oxygen through the oxygen inlet; and a gases outlet; wherein the controller is configured to control the valve based on at least one measurement of oxygen saturation from the blood oxygen saturation sensor; and a patient interface as herein described.

[00232] Features from one or more embodiments or configurations may be combined with features of one or more other embodiments or configurations. Additionally, more than one embodiment or configuration may be used together in a respiratory support system during a process of respiratory support of a patient.

[00233] As used herein the term "(s)" following a noun means the plural and/or singular form of that noun.

[00234] As used herein the term "and/or" means "and" or "or", or where the context allows both.

[00235] The term "comprising" as used in this specification means "consisting at least in part of". When interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

[00236] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

[00237] This disclosure may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features.

[00238] Where specific integers are mentioned herein which have known equivalents in the art to which this disclosure relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[00239] The disclosure consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

[00240] Specific embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow, of which:

[00241] Figure 1A is a front left perspective view of an exemplary configuration patent interface of the present disclosure comprising a nasal interface.

[00242] Figure IB is a front right perspective view of the patient interface.

[00243] Figure 1C is a front left exploded perspective view of the patient interface.

[00244] Figure ID is a front view of the nasal interface. [00245] Figure 2 is a front view of a nasal interface according to the present disclosure schematically showing elements.

[00246] Figure 3A is a perspective view of a schematic of an element of the nasal interface of Figure 2.

[00247] Figure 3B is a front view of a schematic of the element of Figure 3A in a possible configuration.

[00248] Figure 3C is a front view of a schematic of the element of Figure 3A in a possible configuration.

[00249] Figure 4 is a front view of a modification of the nasal interface according to the present disclosure.

[00250] Figure 5 is a front view of a modification of a nasal interface according to the present disclosure.

[00251] Figure 6 is a front view of a modification of a nasal interface according to the present disclosure.

[00252] Figure 7 is a front view of a modification of the nasal interface of Figure 6.

[00253] Figure 8 is a front view of a modification of the nasal interface of Figure 6.

[00254] Figure 9 is a front view of a modification of a nasal interface according to the present disclosure.

[00255] Figure 10 is a front view of a modification of the nasal interface of Figure 9.

[00256] Figure 11 is a front view of the nasal interface of Figure 9 schematically showing elements.

[00257] Figure 12 is a front view of a modification of a nasal interface according to the present disclosure.

[00258] Figure 13 is a front view of a modification of a nasal interface according to the present disclosure.

[00259] Figure 14 is a front view of a modification of a nasal interface according to the present disclosure.

[00260] Figure 15 is a front view of a modification of the nasal interface of Figure 14.

[00261] Figure 16 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00262] Figure 17 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00263] Figure 18 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00264] Figure 19 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00265] Figure 20 is a front view of a modification of prongs of a nasal interface according to Figure ID. [00266] Figure 21 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00267] Figure 22 is a front view of a modification of prongs of a nasal interface according to Figure ID.

[00268] Figure 23 is a front view of a modification of a nasal interface according to Figure ID.

[00269] Figure 24 shows a respiratory therapy system incorporating the patient interface and nasal interface of the present disclosure.

[00270] Figure 25 shows a control loop of the respiratory therapy system for closed loop blood oxygen saturation (SpO2) control.

[00271] Figure 26 shows an alternative respiratory therapy system incorporating the patient interface and nasal interface of the present disclosure.

[00272] Figure 27 shows a sectional view of a patent conduit that can be used in the respiratory therapy systems and/or with the nasal interfaces of the present disclosure.

[00273] Figure 28 shows a sectional view of an alternative patent conduit that can be used in the respiratory therapy systems and/or with the nasal interfaces of the present disclosure.

DETAILED DESCRIPTION

[00274] Patient interfaces can be used for delivering breathing gases to airways of a patient. The patient interfaces may comprise nasal interfaces that can be used to deliver a flow of gases to a patient. Nasal delivery elements, such as nasal prongs or pillows, are inserted into the nose of a patient to deliver the required therapy. The nasal delivery prongs may be desired to seal at the nose to deliver the therapy. One or more of the nasal delivery elements may comprise a nasal pillow to seal at the nose.

[00275] Disclosed is a system to deliver gases to a patient through a nasal interface.

[00276] The system provides an asymmetrical gases flow to each naris, such as resulting in a pressure differential at first and second nasal prongs of the nasal interface. Asymmetrical flow as described herein refers to a flow that differs within the nasal interface such as the nasal prongs or within the nose (e.g. different flows between the nares). In this way, a different flow may be delivered by each nasal prong. An asymmetrical flow may also include partial unidirectional flow.

[00277] Delivery of asymmetrical flow may improve clearance of dead space in the upper airways. A nasal interface as described is configured to produce such asymmetrical flow via flow restricting elements.

[00278] Flow generated by respiratory therapy depends on flow through the nasal interface, which depends on the pressure at each nasal prong. If the pressure is different at each nasal prong, an asymmetric flow of gases will be generated. [00279] If flow, leak, or a combination of flow and leak, is asymmetrical through the nasal interface, the flow through the nose may become asymmetrical during breathing. Partial unidirectional flow may be a type of asymmetrical flow. Partial unidirectional flow may provide improved clearance of anatomical dead space as the air is flushed from the upper airways. Partial unidirectional flow may be more comfortable than total unidirectional flow. Total unidirectional flow herein includes all flow entering a naris by a nasal delivery prong and exiting via the other naris. Partial unidirectional flow as described herein includes flow that may enter the nose via the nares and leave the nose from one naris, flow that may enter the nose through one naris and leave the nose via the nares, or different proportions of flow that may enter the nose through the nares and/or different proportions of flow that may leave the nose through the nares, and may be flow that may enter the nose via the nares and leave the nose from a naris or the nares and optionally via the mouth. If there is a pressure differential between the first and second nasal prongs, during inspiration the first nasal prong will receive more gases flow from a gases inlet than the second nasal prong. During expiration, the second nostril or naris associated with the second nasal prong will expel more gases flow than the first nostril associated with the first nasal prong. The pressure differential between the first and second nasal prongs can change depending on whether the patient's breathing cycle is in an inspiration phase or expiration phase.

[00280] The asymmetrical flow assessment may be applied over a suitable period. For example, the asymmetrical flow assessment may be applied over one breath cycle of the patient or alternatively over a different number of breath cycles of the patient.

[00281] The partially unidirectional flow may reduce turbulence in the patient's nasal cavity, which could improve comfort.

[00282] Figures 1A to ID show an exemplary patient interface 10 that comprises a nasal interface 100 with first and second nasal prongs 111, 112. The nasal interface comprises a gases manifold 120 comprising a gases inlet 121.

[00283] The first nasal prong 111 and the second nasal prong 112 are in fluid communication with the gases inlet 121 through the manifold 120. The gases inlet 121 is positioned at the manifold 120 such that the first nasal prong 111 is more proximal to the gases inlet 121 and the second nasal prong 112 is more distal to the gases inlet 121. The gases manifold 120 forms a manifold chamber 125 to allow the passage of gases therethrough. Therefore, in some configurations the gases inlet 121 is at a side or otherwise biased to a side of the gases manifold 120.

[00284] The first and second prong 111, 112 have flow passages to allow the flow of gases therethrough. The flow passage of the first and second prongs 111, 112 are formed by their respective inner walls. The manifold 120 is in fluid communication with a gases conveying conduit 300 connected by the gases inlet 121. The gases manifold 120 may be removably attached or integrally moulded to the gases conveying conduit 300. [00285] In the configuration shown, a flow of gases passes from the conveying conduit 300, through the gases inlet 121, through the manifold chamber 125 to the first prong 111 and second prong 112 and through their respective flow channels to a patient's nares. Therefore, the direction of gas flow from the gases conveying conduit 300 defines an upstream direction and a downstream direction. However, it is highlighted that gases flow is not limited to one direction. For instance, a patient exhaling may provide a gas flow in the opposite direction, such as through the first and second prongs 111, 112 into the gases manifold 120. However, the upstream and downstream definitions are used herein as defined above.

[00286] In the configuration shown, the first nasal prong 111 and second nasal prong 112 may be formed as part of an interface body 118. The interface body 118 is a face mount for engaging with a patient's face. The first nasal prong 111 and second nasal prong 112 are integrally moulded with or removably attached to the interface body 118.

[00287] The interface body 118 part may be connectable to or engageable with a gases manifold part 120a or may be integrally formed or permanently engaged with the gases manifold part 120a. The interface body 118 and gases manifold part 120a forms the gases manifold 120.

[00288] The interface body 118 may be formed from a soft, flexible material such as silicone, thermoplastic elastomers, or other polymers known in the art. The nasal first and second prongs 111, 112 may be supple and may be formed from a sufficiently thin layer of silicone or other suitable material to achieve this property. The interface body 118 and nasal prongs 111, 112 may, for example, be formed from an elastomeric material that is able to confirm to the geometry of a patient's nostril and/or cheek and provide an effective pneumatic seal.

[00289] The interface body 118 comprises two side arms that extend laterally outward from either side.

[00290] In the configuration shown, the side arms comprise wing portions 113 and 114 extending laterally from either side of the interface body 118. The wing portions 113 and 114 are integrally formed with interface body 118 but may alternatively be separate parts.

[00291] In some configurations, the first and second nasal prongs 111, 112 extend generally upwardly and rearwardly from the interface body 118.

[00292] In some configurations, the second nasal prong 112 is more proximal to the gases inlet 121 and the first nasal prong 111 is more distal to the gases inlet 121.

[00293] The gases inlet 121 is an opening, orifice or port in the gases manifold 120 for a releasable or permanent connection to a conduit, such as the gases-conveying conduit 300. In some arrangements, the gases inlet 121 may form a tube or channel extending from or as part of the gases manifold 120. In some arrangements, the gases inlet 121 has fastening or connection means for securing to a conduit. [00294] The gases manifold 120 may comprise a single gases inlet 121.

[00295] In the configuration shown, the first nasal prong 111 has an opening at its tip or terminal end 131 for delivery of gases from the gases manifold 120. Gases delivered through the first nasal prong 111 exit the first nasal prong 111 via the first terminal end 131. The first nasal prong 111 has a first base 135 at the opposite end of the first nasal prong 111 to the first terminal end 131. The first base 135 is a further opening and connects to the gases manifold 120 and allows the flow of gases from the manifold chamber 125 to the first prong 111. The first base 135 may be integrally formed or removably connected to the interface body 118.

[00296] The second nasal prong 112 has an opening at its tip or terminal end 132 for delivery of gases from the gases manifold 120. Gases delivered through the second nasal prong 112 exit the first nasal prong 112 via the second terminal end 132. The second nasal prong 112 has a second base 136 at the opposite end of the second nasal prong 112 to the second terminal end 132. The second base 136 is a further opening connects to the gases manifold 120 and allows the flow of gases from the manifold chamber 125 to and through the second prong 112. The second base 136 may be integrally formed or removably connected to the interface body 118.

[00297] The first and second prongs 111, 112 may have any suitable shape to seal or be inserted with the nares of the patient. For example, in one configuration, the first and second prongs 111, 112 may be substantially tubular and may be sized to be larger than the nares of a patient but may be supple or flexible to deform and seal with the nares upon insertion into the nares. In an example, the first and/or second prongs 111, 112 are curved, and optionally curved to point to the back of the patient's head in use. The first and/or second prongs 111, 112 may also be configured such that their outlets point towards a midline plane of the nasal interface 100. This midline place may be parallel to the sagittal plane of a patient when the nasal interface 100 is in use. In other words, the outlet of the first and/or second prongs 111, 112 may point towards the patient's sagittal plane when the nasal interface 100 is in use. In a configuration, the first and second prongs 111, 112 may be supple or flexible to deform and sized to form a non-sealing arrangement with the nares. In a configuration, the first and second prongs 111, 112 may not enter the nares but be positioned proximal. In some configurations, the nasal prongs 111, 112 are more supple or flexible than the interface body 118.

[00298] The nasal interface 100 provides a patient with a patient interface suitable for the delivery of high airflow, high humidity gas flow to the patient's nasal cavity/nares. In some configurations, the nasal interface 100 is adapted to deliver a high flow of gases over a wide flow range (e.g. about 8 Ipm, or higher depending on other therapy applications, perhaps such as 10 - 50 Ipm or higher). In some configurations, the nasal interface 100 is adapted to deliver relatively low pressure gases. [00299] The gases manifold part 120a is insertable the interface body 118 to form the gases manifold 120. The interface body 118 and may comprise at least one substantially horizontal side entry passage 118a, 118b to the interior of a base portion or interface body 118 for releasably receiving the outlet of the gases manifold part 120a therethrough.

[00300] The gases manifold part 120a is optionally insertable into the interface body 118 from either of two opposing horizontal directions, i.e. from either left side or the right side. In this manner, the orientation of the gases flow manifold part 120a could be reconfigurable with respect to the interface body 118. In other words, a user may choose to have gases inlet 121 of the manifold part 120a (and the conduit 300 extending therefrom) extend from either the left side or the right side of the interface body 118 of the nasal interface 100 depending on what is most convenient, for example depending on which side of the user the gas source or ventilator is located.

[00301] The interface body 118 may comprise a pair of opposed side entry passages 118a, 118b to the interior of the base portion or interface body 118, each adapted to releasably receive the outlet of the gases manifold part 120a therethrough.

[00302] The interface body 118 is shaped to generally follow the contours of a patient's face around the upper lip area. The interface body 118 is moulded or pre-formed to be able to conform to and/or is pliable to adapt, accommodate and/or correspond with the contours of the user's face, in the region of the face where the cannula is to be located. In some configurations, the interface body 118 includes a portion or dip to accommodate part of a patient's nose and reduce pressure on an underside of the accommodated part.

[00303] A headgear may be used to retain the nasal interface 100 against the patient's face. The headgear comprises a head strap 200. The head strap 200 may be a single continuous length and adapted to extend in use along the patient's cheeks, above the ears and about the back of the head, may be adjustable, and/or may extend around other portions of the patient's head.

[00304] In the exemplary configuration shown, primary end portions 2011 and 2021 of the strap 200 are adapted to releasably connect respective formations 101 and 102 on either side of the nasal interface 100 to hold the nasal interface 100 in position during use. [00305] In one configuration, a clip component is provided at each end portion 2011, 2021 capable of being received and retained within the corresponding formation 101, 102. The clip component may be coupled to the strap at the respective primary end portion. Furthermore, the head strap 200 is adjustable in length to help adjust the strap to the wearer's head. The strap 200 may be formed from a soft and stretchable/elastic material such as an elastic, textile material/fabric that is comfortable to the wearer. Alternatively, the strap 200 may be formed from a substantially more rigid, or less flexible, material such as a hard plastics material. [00306] The headgear may further comprise an additional strap or other headgear component that couples the strap 200 to extend over the patient's crown in use. A crown strap or crown component can have the benefit of pulling the strap 200 up and above the patient's ears in use to improve fit and comfort.

[00307] Generally, but also with reference to Figures 1A to 1C, in one exemplary configuration of an adjustable strap 200, the adjustment mechanism is provided in the form of one or more insertable/removable strap segments or strap extensions 2201.

[00308] Strap segments 2201 of a fixed length can be releasably connected to the main strap 210 to extend its length. The main strap 210 in this configuration comprises a pair of intermediate or secondary end portions 2031, 2041 that are releasably connectable with one another, and that are also releasably connectable with respective ends 2211 and 2221 of the strap segments 2201. When the secondary end portions 2031 and 2041 are connected to one another, the main strap 210 is of a continuous starting length/size for the wearer. To extend the length of the strap 200 beyond this starting length, the main strap 210 can be disconnected at the secondary end portions 2031/2041 and one or more additional strap segments 2201 are connected therebetween.

[00309] A number of strap segments 2201 of varying predetermined lengths may be provided to provide alternative adjustment lengths. For example, one or more strap segments 2201 may be provided having a length within the range of about 1cm to about 10cm, or within the range of about 2cm to about 6cm. The strap segments 220 have lengths of, for example, about 2cm, about 4cm or about 6cm. It will be appreciated that these examples are not intended to be limiting and the length of each strap segments can be of any size as it is dependent on the user and/or application.

[00310] Furthermore, each end 2211, 2221 of each strap segment 2201 may be connectable to a respective end 2211, 2221 of another strap segment 2201 and/or to a respective secondary end portion 2031, 2041 of the main strap 210 to thereby enable a user to combine one or more strap segments 2201 of the same or varying lengths to adjust the overall length of the extension as desired.

[00311] The additional strap segments may be formed from a soft and stretchable/elastic material such as an elastic, textile material/fabric that are comfortable to the wearer. For example, a tubular knitted type head strap or sections of the head straps 210 may be adjusted, particular for comfort over a user's ears.

[00312] It will be appreciated that particular comfort may be achieved from a head strap which is able to provide suitable locating of the nasal interface 100 in a relatively stable position on a user's face, yet simultaneously provide for a relatively loose fit or low tension fit about the user's head.

[00313] Alternatively, the additional strap segments may be formed from a substantially rigid material such as a hard plastics material. [00314] A strap connector 2301 is provided at each of the secondary end portions 2031, 2041 of the main strap 210 and the respective end portions 2031, 2041 of the strap segments 2201.

[00315] Each connector 2301 is provided with a strap connection mechanism at one end to couple to the strap material, and a coupling mechanism at an opposing end to releasably couple the respective end of a similar connector 2301.

[00316] In an alternative, the connector 2301 may be various different forms of adjustable buckles suitable for adjusting the length or tension of the head strap sections 210 which hold the patient interface in position about a user's head.

[00317] It will also be appreciated that the connector 2301 may be located so as to be offset from a mid-point from the rear of a user's head, or may be offset to one side of a user's head. This may be advantageous so as to avoid impinging upon a part of a user's head which may otherwise be, in some positions such as sleeping, uncomfortable for the user.

[00318] In yet a further configuration, the strap segments may be of different lengths, so as to be asymmetrically provided or to help be operational with an offset connector 2301 position. Further, it may be that of the two strap segments 210, one of those straps may be adjustable in length while the other is not. For example, one strap segment 210 may be of a permanent length or permanently connected to the connector 2301.

[00319] In an exemplary configuration, the strap connection mechanism may comprise of a series of internal teeth located within the body of the connector for establishing a friction fit engagement with the respective end of the strap. A hinged jaw of the body is provided and closes upon the teeth to securely retain the end of the strap upon the teeth. The releasable coupling mechanism at the other end comprises a pair of male and female members, such as a protrusion and aperture respectively, both adapted to connect to corresponding male and female members of a similar connector 230. A lug on the protrusion may couple a recess in the female member to provide a snap-fit engagement between the members. It will be appreciated that in alternative configurations, any other suitable connector configuration may be used to releasably connect the secondary end portions of the strap to one another, and to the end portions of the additional strap segments.

[00320] Cannula connectors 2401 are provided at the primary end portions 2011 and 2021 of the main strap 210. These connectors 2401 have a similar strap connection mechanism to the strap connectors 2301 of the secondary end portions 2031 and 2041, but include a clip member, such as a push fit clip 2411, at an end of the connector 2401 opposing the strap ends. The clip 2411 is configured to releasably couple the respective formation 101, 102 at the side of the nasal interface 100. The clip member 2411 may be a bendable part, such as a plastic part, that forms a hinged portion relative to the strap. The clip 2411 may be pre-formed to have a curved shape along its length. In an example, the clip 2411 may be pre-formed with two or more portions angled relative to one another, for example an angle between 0 and 20 degrees. The curve and/or angle allow the clip 2411 to fit the contour of the patient's face in the region of the clip 2411.

[00321] The nasal interface 100 may comprise sleeves 270. Each sleeve 270 may be pre-formed to have a curved shape along its length. In an example, each sleeve 270 may be pre-formed with two or more portions angled relative to one another, for example an angle between 0 and 20 degrees. The curve and/or angle allow the sleeve to fit the contour of the patient's face or cheek in the region of the sleeve in use. Alternatively, the sleeve 270 may take on the shape of a curved sleeve upon engagement with the primary end portion 2011, 2021 or connector 2401 of the head strap 200.

[00322] The sleeve 270 provides a surface region of relatively higher frictional surface material for frictionally engaging with the user's face or facial skin. This surface region is to be positioned for frictional engagement with the facial cheek skin of a user. The surface region is at least localised to the strap or the section of strap which is to be positioned upon the cheeks of a user. The surface region provided with the relatively higher frictional surface material may be of a material that is smooth and comfortable on the skin of the patient. The sleeve 270 or at least the surface region 271 is therefore formed from a relatively softer material than the connector 2401.

[00323] In one configuration, the surface region 271 or the sleeve 270 is formed from a soft Thermoplastic Elastomer (TPE), but may alternatively be formed from another plastics material such as Silicone, or any other biocompatible materials.

[00324] The surface region 271 may be a surface of wider surface area more adjacent to the patient interface than the surface area more distant from the patient interface. In one configuration, the sleeve 270 tapers from a relatively wider surface area 273 to a relatively lesser surface area 274 in a direction extending away from a connection point between the connector 2401 and the nasal interface 100. The width of the sleeve at the end 273 may be the same or similar to the width of the tapered distal end of the corresponding wing portion 113, 114 of the interface body 118. This provides a smooth transition between the nasal interface 100 and the headgear.

[00325] The sleeves 270 may be coloured to provide an identification of the nasal interface 100. As described herein, the nasal interfaces may be provided in different sizes such as small, medium, and large, for example. The sleeves 270 of each of those sizes may comprise different colours to represent the different sizes. Alternatively, or additionally, the sleeves may be coloured in a specific way to represent that the nasal prongs 111, 112 have asymmetrical nasal flow rather than symmetrical.

[00326] Headgear for other forms of interface in addition to nasal cannula may comprise cheek supports 270 as described or similar, at or adjacent either side end of straps of headgear of the interface, which connect to the nasal interface, for frictionally engaging with the user's face to stabilise the mask on the face at the cheeks. Such headgear may again comprise a single head strap adapted to extend in use along the patient's cheeks, above the ears and about the back of the head, with ends comprising clips in any suitable form which couple to the nasal interface on either side (or are permanently attached to the nasal interface).

[00327] Referring to Figures 1A-1C, in the configuration shown, the patient interface 10 comprises a tube retention clip 280. The tube retention clip 280 can support the patient conduit 300 or other gases supply tube from part of the patient interface 10. By supporting the patient conduit 300 or other gases supply tube from or near the nasal interface 100, bending moment applied to the patient conduit 300 or other gases supply tube 300 as a result of asymmetrical flow through the first and second prongs 111, 112 and/or movement of the patient's head will be resisted by the tube retention clip 280, thereby enhancing patient comfort.

[00328] In the configuration shown, the tube retention clip 280 comprises a tubular body 281 for receiving and accommodating a portion of the patient conduit 300 or other gases supply tube therein.

[00329] In the configuration shown, the tube retention clip 280 supports the patient conduit 300 or other gases supply tube from the head gear of the patient interface. In an alternative configuration, the tube retention clip 280 could support the patient conduit 300 or other gases supply tube from part of the nasal interface 100 of the patient interface. For example, the tube retention clip 280 could support the patient conduit 300 or other gases supply tube from the interface body 118. In some configurations, the tube retention clip 280 could support the patient interface from one or either of the wing portions 114, 115 of the nasal interface 100.

[00330] A hook 282 projects from the body 281 to couple the strap or other component of the headgear. In this manner the conduit 300 can be coupled or tethered to the head strap 210 or headgear in use. If the conduit 300 is pulled, the force will be exerted onto the head strap 210 and not directly on the cannula 100. This relocation of force will reduce the likelihood of the prongs 111 and 112 of the nasal interface 100 flicking out of the patient's nostrils.

[00331] One or more tethering points for connecting the tube retention clip 280 may be available on the headgear, with preferably at least two symmetric tethering points on either side of the headgear to increase usability.

[00332] It will also be appreciated the tube retention clip 280 may be removable from or may be a permanent fitting on the patient conduit 300 or other gases supply tube. [00333] The retention clip 280 may be connected (removably or permanently) or retained to a part of the patient interface 10, such as for example a part of an interface which provides for a relatively more rigid region (such as to facilitate support of the patient conduit 300). The retention clip may also be positioned or affixed at a particular location on the patient conduit 300, for example a predetermined location may be provided which holds the retention clip in place.

[00334] In some configurations, one or both of the first prong and second prong 111, 112 ensure that a gap is maintained between the outer surface of the prong and a patient's skin to avoid sealing between the nasal interface 100 and the patient. This provides a gas path for a gas flow around the outer surface of the nasal prongs 111, 112.

[00335] The patient interface 10 may have any one or more of the features and functionality described in PCT publication no. WO 2014/182179 or US patent no. 10,406,311. The contents of those specifications are incorporated herein in their entireties by way of reference.

[00336] As an alternative to a headgear, the patient interface may comprise a securement system of the type described in PCT publication number WO 2012/053910 or US patent no. 10,238,828. The contents of those specifications are incorporated herein in their entirety by way of reference.

[00337] The nasal interface may have any one or more of the features described in relation to the nostril locators of US patent no. 10,918,818. The contents of that specification are incorporated herein in their entirety by way of reference.

[00338] With reference to Figure 2, the patient interface 10 having a nasal interface 100 as described with reference to Figure 1 is shown. Additionally, there is provided at least one element configured or arranged to increase a resistance to the flow of gases passing through the nasal interface or a portion thereof.

[00339] Schematically shown in Figure 2 is a first prong element 201, a second prong element 202 and a manifold element 203 configured or arranged to increase a resistance to the flow of gases passing through the respective first prong 111, second prong 112 and manifold 120.

[00340] The elements 201, 202, 203 used throughout may also be referred to as flow restrictions or flow restrictors.

[00341] Whilst Figure 2 shows the first prong element 201, second prong element 202, and manifold element 203, in various configurations, as detailed below, a single element 201, 202, 203 may be present in the nasal interface 100, or any combination of two elements, such as a second prong element 202 and a manifold element 203 may be present.

[00342] When present, the second prong element 202 is positioned within the second prong 112 and is for increasing a resistance to flow of a flow of gases passing through the second prong 112. The second element 202 may be positioned at or proximal to the second base 136, at or proximal to the second terminal end 132, or at any position between the second terminal end 132 and the second base 136. [00343] In some configurations, a resistance to flow provided by any element 201, 202, 203 described herein may be such that very little flow (negligible flow) or no flow is permitted through the element.

[00344] When present, the manifold element 203 is positioned within the manifold chamber 125 and is for increasing a resistance to flow of a flow of gases passing through the gases manifold 120. The manifold element 203 is positioned between the entrances between the flow channels for the respective first prong 111 and second prong 112, such as between the first base 135 and the second base 136. Therefore, in configurations where the gases inlet 121 is positioned at a side of the gases manifold 120, the flow of gases through the manifold chamber 125 from the gases inlet 121 will be restricted for one proximal prong and not restricted for the other prong. Specifically, where the first prong 111 is proximal to the gases inlet 121, the flow of gases is not restricted to the first base 135 by the manifold element 203 as the gases inlet 121 and the first base 135 are in fluid communication without gases passing through the manifold element 203. The flow of gases through the manifold chamber 125 from the gases inlet 121 to the second base 136 is restricted by the manifold element 203 as the gases inlet 121 and the second base 136 are in fluid communication with gases having to pass through the manifold element 203.

[00345] When present, the manifold element 203 splits the manifold chamber 125 into an upstream portion 141 and a downstream portion 142 at either side of the manifold element 203. The upstream portion 141 is on the gases inlet 121 side of the gases manifold 120.

[00346] When present, the first prong element 201 is positioned within the first prong

111 and is for increasing a resistance to flow of a flow of gases passing through the first prong 111. The first element 201 may be positioned at or proximal to the first base 135, at or proximal to the first terminal end 131, or at any position between the first terminal end 131 and the first base 135.

[00347] Each of the elements 201, 202, 203 when individually present in the nasal interface 100 causes an asymmetrical gases flow at the first prong 111 and second prong

112 and thus at each naris. The asymmetrical flow results in a pressure differential between the first and second nasal prongs 111, 112 and thus the patient's nares. Therefore, a single first prong element 201, second prong element 202 or manifold element 203 may provide a restriction of flow to cause an asymmetrical flow of gases at each prong 111, 112 accordingly. Likewise, a combination of the second prong element 202 and the manifold element 203 (with no first prong element 201 present) will cause a restriction of flow to the second prong 112 which would result in an asymmetrical flow. However, the presence of a first prong element 201 and a second prong element 202 (or a manifold element 203) both restricting a flow of gases in a similar manner at each first prong 111 and second prong 112 would not produce an asymmetrical gases flow. However, in some configurations the elements 201, 202, 203 may be configured to restrict flow in different magnitudes to provide an asymmetrical flow even when combinations restricting flows to both a first prong 111 and second prong 112 are present.

[00348] In some configurations, the nasal prong closest to the gases inlet 121 has no restrictions as the flow of gases is least disrupted by geometry from the gases inlet 121 to the respective nasal prong. Therefore, as is the case of Figure 2, the first nasal prong 111 may not have any first element 201 present. In some configurations when the first prong element 201 is present, at least one of the second prong 112 and gases manifold 120 is devoid of any element or flow restriction. In some configurations when the second prong element 202 is present, at least one of the first prong 111 and gases manifold 120 is devoid of any element or flow restriction. In some configurations when the manifold element 203 is present, at least one of the first prong 111 and second prong 112 is devoid of any element or flow restriction. Each at least one element as described herein causes an asymmetrical flow at the patient's nares. In an example, each at least one element causes an asymmetrical flow at the patient's nares when a flow of gas is provided to the patient, optionally during the patient's inspiratory phase, the patient's expiratory phase or throughout the patient's respiratory cycle. In some configurations, the elements 201, 202, 203 passively cause a flow restriction.

[00349] Whilst the elements 201, 202, 203 are shown as rectangular, these elements 201, 2020, 203 may take any form as is suitable. Examples are provided below in this regard.

[00350] The flow restriction provided by the elements 201, 202, 203 may take various forms depending on the desired difference in flow between the prongs. Referring to Figures 3A to 3C, an element 201, 202, 203 takes the form of a plate or wall 205. The plate 205 is positioned or formed in the prong 111, 112 or manifold chamber 135. The plate 205 is positioned across the passage through which the gases flow. The plate 205 comprises an aperture 207 to allow the flow of gases therethrough. The aperture 207 formed in the first prong element 201, second prong element 202 or manifold element 203 provides a smaller opening than the flow channel and restricts the gases flow therethrough. [00351] In some configurations, the plate 205 is positioned substantially centrally across the passage through which the gases flow.

[00352] The aperture 207 may be centrally located in the plate 205, or may be eccentric within the plate.

[00353] Referring to Figure 3B, the plate 205 has a surface that faces the flow of gases from the inlet 121, e.g. the upstream direction. This is the inlet surface 211. The plate 205 has a surface that faces the opposite direction to the flow of gases from the inlet 121, e.g. the downstream direction. This is the outlet surface 213. The aperture 207 is formed extending between the surfaces such that the plate 205 has a thickness.

[00354] The inlet surface 211 transitions between a flow facing surface to forming the aperture 207, such as the walls of the aperture 207. In Figure 3B, the transition 214 between the inlet surface 211 and the aperture surfaces 207 is a sharp angle transition 214. The sharp angle transition 214 may substantially be a right angle formed between the two surfaces. Alternatively, it may be formed as fillet or chamfer edge. The equivalent fillet or chamfer angle for the sharp angle transition 214 from the inlet surface 211 to the chamfer has an angle between approximately 75° to 110°. The sharp angle 214 causes disruption to the flow of gases such as to cause turbulent flow. This results in the element

201, 202, 203 causing additional disruption to the flow.

[00355] The outlet surface 213 transitions between the aperture 207 and the trailing flow. In Figure 3B, the transition 216 between the aperture 207 and the outlet surface 213 is a smooth angle transition 216 with a fillet or chamfered edge. The equivalent fillet or chamfer angle for the smooth angle transition 216 from the outlet surface 213 to the chamfer has an angle between approximately 30° to 75°. The smooth angle 216 allows the flow of gases to leave the aperture 207 to fill the flow channel past the element 201,

202, 203.

[00356] Referring to Figure 3C, the transition 215 between the inlet surface 211 and the aperture surfaces 207 is a smooth angle inlet transition 215. Therefore, it is similar to the smooth angle outlet transition 216. The equivalent fillet or chamfer angle for the smooth angle transition 215 from the inlet surface 211 to the chamfer has an angle between approximately 30° to 75°.

[00357] In some configurations, the sharp angle inlet transition 214 or smooth angle inlet transition 215 has a greater angle or chamfer angle than that or the smooth angle outlet transition 216. This ensures that the flow of gases is disrupted when entering the aperture 207.

[00358] The varying of the smooth and sharp transitions 214, 215, 216 results in the element 201, 202, 203 having a higher discharge coefficient than an equivalent plate 205 with apertures 207, having the same internal diameter.

[00359] The smooth angle transition 216 at the outlet surface 213 may ensure that a flow of gases through the first prong 111 or second prong 112 with either first prong element 201 or second prong element 202 toward the manifold chamber 125 is less restricted, such as during patient exhalation. Therefore, a build-up of gases in either of a patient's nares is avoided.

[00360] In some configurations, the diameter of the aperture 207 may be reduced at one location, such as proximal to the outlet surface 213, so that the change in cross section creates an increased pressure drop relative to the inlet surface 211 with a larger diameter and thus smoother entry into the elements 201, 202, 203. This change in diameter of the aperture 207 may be formed as a nozzle.

[00361] The aperture 207 when formed as a hole may be any shape, such as round, or may triangular, square, or any polygonal shape. Multiple apertures 207 may be formed in the plate 205. In some examples, a non-perforated but non-contiguous plate 205 with one or more small gaps may be provided, or a contiguous wall with a pattern of perforations may be provided. A porous medium such as a filter may be used as the plate 205. A gap, slit or cut may be formed in the plate 205 either extending vertically or horizontally lengthwise with reference to the plate 205 itself. A perforated wall or plate 205 may have the benefit of reduced acoustic noise generation.

[00362] In some configurations, the elements 201, 202, 203 may have a varied surface texture in the gases flow path to provide a pressure drop through said elements 201, 202, 203. A substantially rougher region may have an increased pressure drop.

[00363] In some configurations a first prong element 201, second prong element 202 or manifold element 203 may be in the form of a valve to cause a pressure drop to restrict the flow. Referring to Figure 4, a patient interface 10 is shown with a nasal interface 100 as described with reference to Figures 1 and 2. The manifold element 203 comprises a manually adjustable flow restrictor 220.

[00364] In this configuration, the gases manifold 120 has the manifold element 203 connected to or formed with the flow restrictor 220 adjustment mechanism that can be actuated from the exterior of the gases manifold 120.

[00365] In some configurations, the flow restrictor 220 has a slider 221 disposed on the exterior of the gases manifold 120 that is used to adjust the position of a body 222 of the flow restrictor 220 within the manifold chamber 125. The restrictor body 222 provides a variable opening through the manifold chamber 125 by modifying how much of the flow path cross-sectional area is 'open' or effective and how much of the gases flow passes through the manifold element 203 to the second prong 112. In some configurations, the manifold chamber 125 gradually narrows between the first base 135 and second base 136. The flow restrictor 220 is movable along the manifold chamber 125, such as in a direction toward or away from the gases inlet 121 such that the channel between the first base 135 and second base 136 in the manifold chamber 125 is varied. In use, the flow restrictor 220 is moved closer to the first prong 111 to impede flow to the second prong 112 by actuating the slider 221 along the outside of the gases manifold 120. Depending on the size or height of the body 222, the degree of restriction may be more/less significant. Conversely, moving the element towards the second prong 112 reduces the restricting effecting on flow passing to this second prong 112 as the gases flow path in the manifold chamber 125 is less restricted.

[00366] In some arrangements, the flow restrictor 220 may be moved further into the manifold chamber 125 to provide a smaller opening, such as a vertical movement. Therefore, the cross-sectional area of the flow path is varied by the body 222 leaving a smaller effective aperture for the flow. These movements may both be applied in a single flow restrictor 220. [00367] Referring to Figure 5, a patient interface 10 is shown with a nasal interface 100 as described with reference to Figures 1, 2 and 4. The flow restrictor 220 of the manifold element 203 is replaced with a rotatable restrictor 225.

[00368] The rotatable restrictor 225 is arranged extending through the gases manifold 120 such that an internal portion is positioned within the manifold chamber 125 and an external portion at the exterior of the gases manifold 120. The rotatable restrictor 225 is adjustable to increase or decrease the flow of gases through the manifold chamber 125 downstream of the manifold element 203. The rotatable restrictor 225 is a screw to allow rotation to move the rotatable restrictor 225 further into the manifold chamber 125 to effectively reduce an aperture of flow therethrough, or to increase the aperture of gases flow therethrough. The adjustment is made by the rotation of the external portion of the rotatable restrictor external to the gases manifold 120. Therefore, the flow of gases from the inlet 121 is restricted at the second prong 112 by the rotatable adjustor 225 and the amount of restriction can be varied.

[00369] The screw thread of the rotatable restrictor 225 assists in retaining the manifold element 203 in place, allowing a clinician to safely configure the nasal interface 100 as desired, without the risk of the manifold element 203 being bumped or dislodged at a later point in time.

[00370] The valve of the manifold element 203, such as the flow restrictor 220 or rotatable restrictor 225 may be manually or electronically controlled.

[00371] Whilst reference is made to the manifold element 203 in Figures 4 and 5, either of the first prong element 201 or second prong element 202 may utilise such a valve. Furthermore, the sliding or rotating functions of the flow restrictor 220 or rotatable restrictor 225 valves may be combined.

[00372] Referring to Figure 6, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as described with reference to Figure 1 and may optionally be combined with other configurations described throughout this document.

[00373] In this configuration, a manifold opening 230 is formed in the gases manifold 120 wall. The manifold opening 230 allows a portion of gases to pass through it thus out of the manifold chamber 125. The manifold opening 230 may comprise one or a plurality of apertures.

[00374] In this configuration, the manifold element 203, such as described elsewhere in this document, is present. Therefore, the manifold chamber 125 is split into an upstream portion 141 and a downstream portion 142 at either side of the manifold element 203. The upstream portion 141 is at the gases inlet 121 side of the manifold chamber 125. The manifold opening 230 is positioned in the downstream portion 142.

[00375] In some configurations, the manifold opening 230 is positioned on the wall of the gases manifold 120 generally opposite the gases inlet 121. In other configurations, the manifold opening 230 is positioned on the wall of the gases manifold 120 generally opposite the second base 136. In some configurations, these may be the same location.

[00376] The manifold element 203 is a restriction to a gases flow as described above with reference to Figure 2. Therefore, the upstream portion 141 is generally at a higher pressure as flow is restricted into the downstream portion 142 by the manifold element 203. This is particularly the case during patient inhalation. Therefore, more of the gases flow will travel through the un imped ed/unrestricted first prong 111, compared to the second prong 112.

[00377] Upon patient expiration, gases may leak into the ambient environment where the second prong 112 is non-sealing. Gases may also flow back into gases manifold 120 by passing back through the second prong 112. Where the manifold element 203 is present, this may cause an increase in pressure in the downstream portion 142 as the gases flow may be restricted from passing through the manifold element 203. The manifold opening 230 allows some gases to vent to the environment. In this way, in some configurations, the amount of pressure experienced can be prevented from reaching undesirable levels in the nasal interface 100.

[00378] Factors which may cause an increase in pressure in the downstream portion 142 also include excessive occlusion or the naris or nares of the patient. In some cases this may be caused by improper interface size selection.

[00379] The manifold opening 230 may function as an expiratory vent.

[00380] The venting of some the flow of gases through the manifold opening 230 during inhalation may occur such that not all of the gases that pass from the upstream portion 141 to the downstream portion 142 pass through the second prong 112. However, even if some amount of the gases flow does not pass into the second prong 112 and instead vent to the environment through the manifold opening 230, the increased pressure will have the effect of reducing the exhaled flows from the naris associated with the second prong 112. This has the benefit of increasing to the asymmetry that is also enabled by the positioning of the manifold element 203.

[00381] Referring to Figure 7, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as described with reference to Figure 6 and includes the manifold opening 230 formed in the gases manifold 120 wall.

[00382] In this configuration, the manifold opening 230 is configured to be connected to a pressure drop component 232. The component 232 is configured to prevent overpressure from occurring. This assists with the possible over pressure in the downstream portion 142 of the manifold chamber 125 such as described above with reference to the manifold opening 230 itself.

[00383] A number of configurations are possible for the component 232. In one configuration, the component 232 is a porous medium, such as a filter. In another configuration the component 232 is a nozzle. Other components 232 that result in a generally known pressure drop are also usable.

[00384] In some configurations, the component 232 is an auxiliary tube. The auxiliary tube may be a nasogastric tube, i.e. extending to at least one of the first prong 111 or second prong 112.

[00385] In a further configuration, the component 232 is a valve. The valve may be a pressure relief valve, with a defined threshold of pressure to at which it opens. In other configurations the valve is dependent on the flow rate to increase the flow rate based on a flow-pressure relationship. Therefore, the pressure in the downstream portion 142 is controlled and allowed to release in a controlled manner whilst maintaining the asymmetric flow.

[00386] For clarity, in some configurations, the manifold opening 230 and component 232 may be combined, such that the manifold opening 230 is a nozzle, valve, porous medium, auxiliary tube or other component itself, rather than an opening leading to such a component. In one example, the manifold opening 230 and component 232 is a one-way valve that allows insertion of an auxiliary tube, e.g. a nasogastric tube. The one-way valve may be a flexible valve.

[00387] The component 232 may be manually or electronically controllable. Such as with a valve, it may be controllable to open or close in response to a pressure threshold. [00388] In some configurations, the component 232 is a Bubble CPAP (BCPAP) bubbling chamber, which is configured to control pressure. The use of a Bubble CPAP allows the indication of the minimum pressure observed. For instance, if there is bubbling when set at 2 cml-hO, that indicates the positive end expiratory pressure (PEEP). Therefore, a clinician or caregiver can configure the component 232 to alter the pressure or flow. Flow and pressure can be configured independently.

[00389] In some configurations, the leak or venting of gases into the ambient environment at the non-sealing prong 111, 112 and/or at the manifold opening 230 reduces positive end expiratory pressure (PEEP). Therefore, a therapy profile is varied as a result of the venting function.

[00390] In the configuration of Figures 6 and 7, a manifold element 203 has been described. However, a manifold element 203 as described does not need to be present. Instead, in some configurations, where a preferential flow is provided to a first or second prong 111, 112, then the manifold opening 230 may still be implemented to assist with the pressure whilst maintaining the asymmetrical flow. Furthermore, in some configurations that include a manifold opening 230, the first prong element 201 or second prong element 202 may be present, or other features are present to cause asymmetric flow as described throughout this document. The manifold opening 230 and, optionally, pressure drop component 232 reduce the risk of pressure injury, such as from incorrect fitting. [00391] Referring to Figure 8, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as described with reference to Figure 2.

[00392] In this arrangement the manifold element 203 is formed as a one-way valve 204. Therefore, a part of the flow restriction is to prevent flow from the downstream portion 142 to flow through the manifold element 203 into the upstream portion 141 when the one-way valve 204 is closed.

[00393] The one-way valve 204 may also function as flow restriction such as described with reference to the manifold element 203 elsewhere in this document. Therefore, the valve may provide a restriction in the flow, such as having a smaller opening than compared to the cross-section of the manifold chamber 125 to reduce a flow of gases from the upstream portion 141 to the downstream portion 142. Therefore, asymmetrical flow between the first 111 and second prongs 112 is provided.

[00394] In some configurations, the one-way valve 204 is a duckbill valve.

[00395] As pressure may build up within the downstream portion 142 of the manifold chamber 125 by the implementation of the one-way valve 204, the arrangement may be combined with the manifold opening 230 as shown in Figure 8 and described with reference to Figure 6 above. Likewise, a pressure drop component 232 as described with reference to Figure 7 may also be implemented.

[00396] Figure 9 shows an exemplary patient interface 10 that comprises a nasal interface 100 with a first and second nasal prongs 111, 112. Parts of the patient interface 10 are similar to as described with reference to Figures 1 and similar reference signs are used herein for like-features.

[00397] The nasal interface comprises a gases manifold 120 comprising a first gases inlet 121 and a second gases inlet 122. The gases manifold 120 forms a manifold chamber 125 to allow the passage of gases therethrough. The nasal interface 100 comprises a flow altering feature to provide an asymmetrical flow at one of the prongs 111, 112.

[00398] The first nasal prong 111 and the second nasal prong 112 are in fluid communication with the first gases inlet 121 and second gases inlet 122 through the gases manifold 120. The first gases inlet 121 is positioned at the gases manifold 120 such that the first nasal prong 111 is more proximal to the first gases inlet 121 and the second nasal prong 112 is more distal to the first gases inlet 121. The second gases inlet 122 is positioned at the gases manifold 120 such that the second nasal prong 112 is more proximal to the second gases inlet 122 and the first nasal prong 111 is more distal to the second gases inlet 122.

[00399] In some configurations, the position of the prongs are reversed such that second nasal prong 112 is more proximal to the first gases inlet 121 and the first nasal prong 111 is more proximal to the second gases inlet 122. [00400] In some configurations the first gases inlet 121 and second gases inlet 122 are at opposing sides of the gases manifold 120. In other configurations, the first gases inlet 121 and second gases inlet 122 are arranged next to one another.

[00401] The first and second prong 111, 112 have flow passages to allow the flow of gases therethrough. The flow passage of the first and second prongs 111, 112 are formed by their respective inner walls.

[00402] The gases manifold 120 is in fluid communication with a gases conveying conduit 300 connected to the gases manifold 120 by the first gases inlet 121 and the second gases inlet 122.

[00403] In some configurations, the gases conveying conduit 300 has a first gases conveying conduit 301 connected to the first gases inlet 121, and a second gases conveying conduit 302 connected to the second gases inlet 122. The gases conveying conduit 300 may be split, such as by a Y-piece into a first conveying conduit 301 and a second conveying conduit 302. In some other configurations, the first gases-conveying conduit 301 and second gases-conveying conduit 302 are connected directly to a flow generator(s). The gases manifold 120 may be removably attached or integrally moulded to the gases conveying conduit 300, first gases conveying conduit 301, or second gases conveying conduit 302.

[00404] The first and second gases inlets 121, 122 are openings, orifices or ports in the gases manifold 120 for a releasable or permanent connection to a conduit, such as the first gases-conveying conduit 301 or second gases-conveying conduit 302. In some arrangements, the first and second gases inlets 121, 122 may form a tube or channel extending from or as part of the gases manifold 120. In some arrangements, the first or second gases inlets 121, 122 have fastening or connection means for securing to a conduit. [00405] In the configuration shown, a flow of gases passes from the first gases conveying conduit 301, through the gases inlet 121, through the manifold chamber 125 to the first prong 111 and second prong 112 and through their respective flow channels to a patient's nares. A flow of gases also passes from the second gases conveying conduit 302, through the gases inlet 122, through the manifold chamber 125 to the second prong 112 and first prong 111 and through their respective flow channels to a patient's nares. However, in some configurations, gases may flow in the opposite direction, such as during exhalation, where a gas flow from a patient's nares may flow through the first and second prong 111, 112 into the gases manifold 120.

[00406] In the configuration shown, the first nasal prong 111 and second nasal prong 112 may be formed as part of an interface body 118. The interface body 118 is a face mount for engaging with a patient's face. The first nasal prong 111 and second nasal prong 112 are integrally moulded with or removably attached to the interface body 118. [00407] The interface body 118 part may be connectable to or engageable with the gases manifold 120 part or may be integrally formed or permanently engaged with the gases manifold 120 part.

[00408] The interface body 118 may be formed from a soft, flexible material such as silicone, thermoplastic elastomers, or other polymers known in the art. The nasal first and second prongs 111, 112 may be supple and may be formed from a sufficiently thin layer of silicone or other suitable material to achieve this property. The interface body 118 and nasal prongs 111, 112 may, for example, be formed from an elastomeric material that is able to confirm to the geometry of a patient's nostril and/or cheek and provide an effective pneumatic seal.

[00409] The interface body 118 comprises two side arms that extend laterally outward from either side. In the configuration shown, the side arms comprise wing portions 113 and 114 extending laterally from either side of the interface body 118. The wing portions 113 and 114 are integrally formed with interface body 118 but may alternatively be separate parts.

[00410] In some configurations, the first and second nasal prongs 111, 112 extend generally upwardly and rearwardly from the interface body 118.

[00411] In the configuration shown, the first nasal prong 111 has an opening at its tip or terminal end 131 for delivery of gases from the gases manifold 120. Gases delivered through the first nasal prong 111 exit the first nasal prong 111 via the first terminal end 131. The first nasal prong 111 has a first base 135 at the opposite end of the first nasal prong 111 to the first terminal end 131. The first base 135 is a further opening and connects to the gases manifold 120 and allows the flow of gases from the manifold chamber 125 to the first prong 111. The first base 135 may be integrally formed or removably connected to the interface body 118.

[00412] The second nasal prong 112 has an opening at its tip or terminal end 132 for delivery of gases from the gases manifold 120. Gases delivered through the second nasal prong 112 exit the first nasal prong 112 via the second terminal end 132. The second nasal prong 112 has a second base 136 at the opposite end of the second nasal prong 112 to the second terminal end 132. The second base 136 is a further opening connects to the gases manifold 120 and allows the flow of gases from the manifold chamber 125 to and through the second prong 112. The second base 136 may be integrally formed or removably connected to the interface body 118.

[00413] The first and second prongs 111, 112 may have any suitable shape to seal or be inserted with the nares of the patient. For example, in one configuration, the first and second prongs 111, 112 may be substantially tubular and may be sized to be larger than the nares of a patient but may be supple or flexible to deform and seal with the nares upon insertion into the nares. In another configuration, the first and second prongs 111, 112 may be supple or flexible to deform and sized to form a non-sealing arrangement with the nares. For instance, the first and second prongs 111, 112 may not enter the nares but be positioned proximal. In some configurations, the nasal prongs 111, 112 are more supple or flexible than the interface body 118.

[00414] The first gases-conveying conduit 301 and second gases conveying conduit 302, or the first gases inlet 121 or second gases inlet 122, may be configured to provide an asymmetrical flow to the first prong 111 and the second prong 112.

[00415] In some configurations, the flow altering features to provide an asymmetric flow include the conduits 301, 302 or inlets 121, 122 having different (unequal) internal passage diameters (lumens), such as when the passages are circular. The difference in diameters result in different characteristics of the flows of gases through the first gases inlet 121 and second gases inlet 122 and thus to the respective proximal nasal prong 111, 112.

[00416] In some configurations, the diameter of the internal passage of the first gases conveying conduit 301 or first gases inlet 121 is larger than the diameter of the internal passage of the second gases conveying conduit 302 or second gases inlet 122. Alternatively, the diameter of the internal passage of the first gases conveying conduit 301 or first gases inlet 121 is smaller than the diameter of the internal passage of the second gases conveying conduit 302 or second gases inlet 122.

[00417] In some configurations, the flow altering features to provide an asymmetric flow, include the conduits 301, 302 or inlets 121, 122 having different internal passage cross-sections (lumens), such as when the passages are non-circular shapes. Whilst not limited to such, non-circular shapes include oval shapes, straight sided shapes, or any polygonal shape. A combination of a circular internal passage for one of the conduits 301, 302 or inlets 121, 122 and a non-circular shape for another of the conduits 301, 302 or inlets 121, 122 may also be provided. The difference in cross-sections between the conduits

301, 302 or inlets 121, 122 result in different characteristics of the flows of gases through the first gases inlet 121 and second gases inlet 122 and thus to the respective proximal nasal prong 111, 112.

[00418] In some configurations, the cross-section of the internal passage of the first gases conveying conduit 301 or first gases inlet 121 is larger than the cross-section of the internal passage of the second gases conveying conduit 302 or second gases inlet 122. Alternatively, the cross-section of the internal passage of the first gases conveying conduit 301 or first gases inlet 121 is smaller than the cross-section of the internal passage of the second gases conveying conduit 302 or second gases inlet 122.

[00419] In some configurations, the flow altering features to provide an asymmetric flow include the conduits 301, 302 or inlets 121, 122 having different length internal passages (lumens). For instance, the gases conveying conduit 300 may split at different parts to provide the first gases-conveying conduit 301 and second gases conveying conduit

302. Alternatively or additionally, in some configurations, the length of tubing from a Y- piece may have different lengths for first gases-conveying conduit 301 and second gases conveying conduit 302. Alternatively or additionally, the gases first inlet 301 and gases second inlet 302 may also be formed as having different length tubes (that connect to the gases conveying conduits 301, 301) extending from the gases manifold 120. The difference in lengths result in different characteristics of the flows of gases through the first gases inlet 121 and second gases inlet 122 and thus to the respective proximal nasal prong 111, 112.

[00420] In some configurations, the length of the first gases conveying conduit 301 or first gases inlet 121 is longer than the length of the second gases conveying conduit 302 or second gases inlet 122. Alternatively, the length of the first gases conveying conduit

301 or first gases inlet 121 is shorter than the length of the second gases conveying conduit

302 or second gases inlet 122.

[00421] In some configurations, the flow altering features to provide an asymmetric flow include the conduits 301, 302 or inlets 121, 122 comprising internal flow modification elements or relief features. Such elements may include, but are not limited to fins, baffles, protrusions, dividers, vanes, or any other restrictions. The flow modification elements may be different between the conduits 301, 302 or inlets 121, 122 or may only be present in one of the conduits 301, 302 or inlets 121, 122. The flow modification elements result in result in different characteristics of the flows of gases through the first gases inlet 121 and second gases inlet 122 and thus to the respective proximal nasal prong 111, 112. The flow modification elements may be elements as described elsewhere in this document, such as those for the first and second prongs 111, 112.

[00422] In some configurations, the internal passage of the first gases conveying conduit 301 or first gases inlet 121 comprise internal flow modification elements (or relief features) whereas the internal passage of the second gases conveying conduit 302 or second gases inlet 122 does not. Alternatively, the internal passage of the first gases conveying conduit 301 or first gases inlet 121 does not comprise internal flow modification elements whereas the internal passage of the second gases conveying conduit 302 or second gases inlet 122 does comprise internal flow modification elements. Alternatively, the internal passage of the first gases conveying conduit 301 or first gases inlet 121 comprises internal flow modification elements that have a larger impact on the flow of internal flow modification elements of the internal passage of the second gases conveying conduit 302 or second gases inlet 122. Alternatively, the internal passage of the first gases conveying conduit 301 or first gases inlet 121 comprises internal flow modification elements that have a smaller impact on the flow of internal flow modification elements of the internal passage of the second gases conveying conduit 302 or second gases inlet 122. [00423] Referring to Figure 10, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as described with reference to Figure 9 and includes the first gases inlet 121 and second gases inlet 122. [00424] Additionally, in this configuration, the first gases-conveying conduit 301 and second gases conveying-conduit 302 are connected to different gas flows. Therefore, the first gases-conveying conduit 301 and second gases conveying-conduit 302 do not split from a single gases-conveying conduit 300.

[00425] The first gases-conveying conduit 301 is connected to (i.e. in fluid communication with) a first gases flow 303 and the second gases conveying-conduit 302 is connected to (i.e. in fluid communication with) a second gases flow 304. The first gases flow 303 and second gases flow 304 have different flow characteristics as flow altering features, such as different flow rates, or even flow direction. Therefore, the different flow characteristics of the first gases flow 303 and second gases flow 304 result in an asymmetrical flow at the first prong 111 and second prong 112 due to the different flows entering the gases manifold 120 proximal to the first prong 111 and second prong 112. For instance, a different gas pressure is formed near the entry (base 135, 136) of each prong 111, 112. In the case of one of the first gases flow 303 or second gases flow 304 having a negative pressure, such as being a suction, a different gas pressure is formed near the entry (base 135, 136) of each prong 111 112 resulting in an asymmetrical flow.

[00426] In some configurations, the flow altering features to provide an asymmetric flow includes the first gases flow 303 delivering a gas flow at a higher rate than the second gases flow 304 and thus to the respective proximal prongs 111, 112. Alternatively, the first gases flow 303 delivers a gas flow at a lower rate than the second gases flow 304 and thus to the respective proximal prongs 111, 112.

[00427] In some configurations, the flow altering features to provide an asymmetric flow includes the first gases flow 303 having a gas flow at a positive pressure and the second gases flow 304 having a gas flow at a negative pressure relevant to ambient pressure. Alternatively, the first gases flow 303 has a gas flow at a negative pressure and the second gases flow 304 has a gas flow at a positive pressure.

[00428] In some configurations, to prevent excess mixing of the first gases flow 303 and second gases flow 304, a manifold element 203 as described elsewhere in this document may be provided between the first prong 111 and second prong 112, and thus first inlet 121 and second inlet 122. The manifold element 203 may partially restrict flow or may completely restrict flow.

[00429] Referring to Figure 11, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as described with reference to Figure 9 and includes the first gases inlet 121 and second gases inlet 122.

[00430] Additionally, in this configuration, there are provided a first prong element 201, a second prong element 202, a manifold element 203, first gases inlet element 209 and second gases inlet element 208 as flow altering features for increasing a resistance to the flow of gases passing therethrough. The first prong element 201, second prong element 202, and manifold element 203 may be the same as those described elsewhere in this document, such as with reference to Figure 2.

[00431] Whilst Figure 11 shows the first prong element 201, second prong element 202, manifold element 203, first (gases) inlet element 209 and second (gases) inlet element 208 in configurations as detailed below, a single element 201, 202, 203, 208, 209 may be present in the nasal interface 100, or any combination of elements may be present. [00432] The elements 201, 202, 203, 208, 209 used throughout may also be referred to as flow restrictors or flow restrictions.

[00433] When present, the second prong element 202 is positioned within the second prong 112 and is configured increase a resistance to a flow of gases passing through the second prong 112. The second element 202 may be positioned at or proximal to the second base 136, at or proximal to the second terminal end 132, or at any position between the second terminal end 132 and the second base 136.

[00434] In some configurations, a resistance to flow provided by any element 201,

202, 203, 208, 209 described herein may be such that very little flow (e.g. negligible flow) or no flow is permitted through the element.

[00435] When present, the manifold element 203 is positioned within the manifold chamber 125 and is for increasing a resistance to flow of a flow of gases through the gases manifold 120. The manifold element 203 is positioned between the entrances between the flow channels for the respective first prong 111 and second prong 112, such as between the first base 135 and the second base 136. Likewise, the manifold element 203 is positioned between the first gases inlet 121 and second gases inlet 122. Therefore, as the first gases inlet 121 is positioned substantially at one side of the gases manifold 120 proximal to the first prong 111, the flow of gases through the manifold chamber 125 from the first gases inlet 121 will be restricted for the second prong 112 positioned on the opposing side of the manifold element 203, but not restricted for the other first prong 111 proximal to the first gases inlet 121. Likewise, as the second gases inlet 122 is positioned substantially at the other side of the gases manifold 120 proximal to the second prong 112, the flow of gases through the manifold chamber 125 from the second gases inlet 122 will be restricted for the first prong 111 positioned on the opposing side of the manifold element

203, but not restricted for the second prong 112 proximal to the second gases inlet 122.

[00436] When present, the first prong element 201 is positioned within the first prong 111 and is for increasing a resistance to flow of a flow of gases through the first prong 111. The first element 201 may be positioned at or proximal to the first base 135, at or proximal to the first terminal end 131, or at any position between the first terminal end 131 and the first base 135.

[00437] When present, the first gases inlet element 209 is positioned proximal to the first inlet 121 and is for increasing a resistance to flow of a flow of gases through the first inlet 121, such as into the manifold chamber 125 from the first gases-conveying conduit 201. The first inlet element 209 may be positioned at any location between the first gases- conveying conduit 301 and to a location within the gases manifold 120 before the first base 135. In some arrangements, where the first gases inlet 121 is a tube or channel, the first inlet element 209 is positioned within the channel or at an end of the channel.

[00438] When present, the second gases inlet element 208 is positioned proximal to the second inlet 122 and is for increasing a resistance to flow of a flow of gases through the second inlet 122, such as into the manifold chamber 125 from the second gases- conveying conduit 302. The second inlet element 208 may be positioned at any location between the second gases-conveying conduit 302 and to a location within the gases manifold 120 before the second base 136. In some arrangements, where the second gases inlet 122 is a tube or channel, the second inlet element 208 is positioned within the channel or at an end of the channel.

[00439] Each of the elements 201, 202, 203, 208, 209 either on their own or in combination cause an asymmetrical gases flow through the first prong 111 and second prong 112 and thus at each naris. Therefore, a single first prong element 201, second prong element 202, manifold element 203, second inlet element 208, or first inlet element 209 may provide a restriction of flow to cause an asymmetrical flow of gases through each prong 111, 112 accordingly. In the case of the second inlet element 208 or first inlet element 209, the restriction in flow caused by a single element 208, 209 has a similar effect to that described with reference to Figure 9 and the different gases-conveying conduit 301, 302 or gases inlet 121, 122 characteristics. Therefore, the flow through the first or second gases inlet 121, 122 will be different to the other gases inlet and thus result in a different flow provided to the proximal nasal prong 111, 112.

[00440] In some configurations a single element 201, 202, 203, 208, 209 is present and the other elements are not-present. Therefore, at least one of the first prong 111, second prong 112, manifold chamber 125, first inlet 121 or second inlet 122 is unrestricted to flow by, for example, an element 201, 202, 203, 208, 209.

[00441] A combination of two or more of the elements 201, 202, 203, 208, 209 will also cause a restriction of flow to at least one of the first prong 111 or second prong 112 which will result in an asymmetrical flow.

[00442] Whilst variations in the magnitude of flow restriction through each of the elements 201, 202, 203, 208, 209 in various combinations allow for asymmetrical flow at the prongs 111, 112, a non-limiting explanation of some combinations are as follows: [00443] 1) The first inlet element 209 in combination with the second inlet element 208 each configured to increase the resistance to flow of a flow of gases entering the gases manifold 120 through the first gases inlet 121 and second gases inlet 122 respectively. Each of the first inlet element 209 and second inlet element 208 have different properties to affect the flow in a different manner. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical. [00444] In this arrangement, in some configurations, there is no first prong element 201, second prong element 202 or manifold element 203.

[00445] 2) The first inlet element 209 in combination with the manifold element

203 each configured to increase the resistance to flow of a flow of gases therethrough. Therefore, flow to the first prong 111 through the first gases inlet 121 is restricted by the first inlet element 209. However, the manifold element 203 also ensures that flow through the second gases inlet 122 to across the manifold chamber 125 to the first prong 111 is also restricted. There is no (or less) resistance to flow from the second gases inlet 122 to the second prong 112. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical.

[00446] In this arrangement, in some configurations, there is no first prong element 201, second prong element 202, or second inlet element 208.

[00447] 3) The second inlet element 208 in combination with the manifold element 203 each configured to increase the resistance to flow of a flow of gases therethrough. Therefore, flow to the first prong 112 through the second gases inlet 122 is restricted by the second inlet element 208. However, the manifold element 203 also ensures that flow through the first gases inlet 121 across the manifold chamber 125 to the second prong 112 is also restricted. There is no (or less) resistance to flow from the first gases inlet 121 to the first prong 111. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical.

[00448] In this arrangement, in some configurations, there is no first prong element 201, second prong element 202 or first inlet element 209.

[00449] 4) The first prong element 201 and the second prong element 202 each configured to increase the resistance to flow to a flow of gases entering the first prong 111 and second prong 112 respectively. Each of the first prong element 201 and second prong element 202 have different properties to affect the flow in a different manner. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical.

[00450] In this arrangement, in some configurations, there is no first inlet element 209, second inlet element 208 or manifold element 209.

[00451] 5) The first inlet element 209 in combination with the manifold element

203 and the first prong element 201 each configured to increase the resistance to flow of a flow of gases therethrough. Therefore, flow to the first prong 111 through the first gases inlet 121 is restricted by the first inlet element 209 and the first prong element 201. However, the manifold element 203 also ensures that flow through the second gases inlet 122 to across the manifold chamber 125 to the first prong 111 is also restricted. There is no (or less) resistance to flow from the second gases inlet 122 to the second prong 112. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical. [00452] In this arrangement, in some configurations, there is no second prong element 202, or second inlet element 208. In some arrangements, the manifold element 203 may be removed with the first prong element 201 carrying out a similar function.

[00453] 6) The second element 208 in combination with the manifold element

203 and the second prong element 202 each configured to increase the resistance to flow of a flow of gases therethrough. Therefore, flow to the second prong 112 through the second gases inlet 122 is restricted by the second inlet element 208 and the second prong element 202. However, the manifold element 203 also ensures that flow through the first gases inlet 121 to across the manifold chamber 125 to the second prong 112 is restricted. There is no (or less) resistance to flow from the first gases inlet 121 to the first prong 111. Therefore, the flow to each prong 111, 112 and thus each naris is asymmetrical.

[00454] In this arrangement, in some configurations, there is no first prong element 201, or first inlet element 209. In some arrangements, the manifold element 203 may be removed and the second prong element 202 carries out a similar function of restricting flow from the first gas inlet 121 to the second prong 112.

[00455] Whilst the elements 201, 202, 203 are shown as rectangular, these elements 201, 202, 203, 208, 209 may take any form as is suitable. For example, these elements may be an orifice plate with a single aperture, an orifice plate with multiple aperture, a Venturi throat or a nozzle. Other examples are provided throughout the present disclosure. [00456] The present configuration as described with reference to Figure 11 may be combined with any other part of this disclosure. For instance, the form of the elements, such as apertures 207 formed in a plate or wall 205 as described with reference to Figures 3A to 3C may be applied to the elements 201, 202, 203, 208, 209 of the present configuration. Likewise, a manual flow restriction 220 having a slider 221 or being a rotatable resistor 225 as described with reference to Figures 4 and 5 may likewise be applied to the elements 201, 202, 203, 208, 209 of the present configuration. The variations in flow from a first gases flow 303 and second gases flow 304 may be applied in combination with the present configuration. The manifold opening 230 and, optionally, pressure drop component 232 as described with reference to Figures 6 to 8 may likewise be applied to the present configuration.

[00457] Referring to Figure 12, a patient interface 10 having a nasal interface 100 is shown. The arrangement as that described with reference to Figure 1.

[00458] Additionally, in this configuration, the gases-conveying conduit 300 is in fluid communication with a first gases flow 303, such as described with reference to Figure 10 and the first gases-conveying conduit 301. The first gases flow 303 provides a gases flow with a particular set of characteristics, such as flow rate or flow velocity.

[00459] The nasal interface 100 of this configuration further comprises an auxiliary gases-conveying conduit 305. The auxiliary gases-conveying conduit 305 is smaller than the gases-conveying conduit 300, for example, the internal diameter of a lumen of the auxiliary gases-conveying conduit 305 is smaller than the internal diameter of a lumen of the gases-conveying conduit 300. The auxiliary gases-conveying conduit 305 is smaller than the first prong 111. For example, the internal diameter of a lumen of the auxiliary gases-conveying conduit 305 is smaller than the internal diameter of the flow passage of the first prong 111.

[00460] The auxiliary gases-conveying conduit 305 is connected to (in fluid communication with) the second gases flow 304 as described with reference to Figure 10. Therefore, the second gases flow 304 has different characteristics to the first gases flow 303.

[00461] The auxiliary gases-conveying conduit 305 is positioned in the gases- conveying conduit 300 and extends into the manifold chamber 125. The auxiliary gases- conveying conduit 305 terminates in the first nasal prong 111 and thus has a gases outlet into the first prong 111. As the auxiliary gases-conveying conduit 305 is smaller than the first prong 111 and the gases conveying conduit 300, it does not occlude the conduits and allows the flow of the first gases flow 303 through the conduits also.

[00462] The second gases flow 304 through auxiliary gases-conveying conduit 305 results in an asymmetrical flow at the first prong 111 and second prong 112 as the different gas characteristics are directed to the first prong 111 only and thus a single naris of the patient. The gases flow from the first gases flow 303 is directed to the second prong 112 without any flow restriction.

[00463] The different gas characteristics of the first gases flow 303 and second gases flow 304 may also be a negative pressure as described with reference to Figure 10. Therefore, a lower dynamic pressure is provided at one of the nasal prongs 111, 112.

[00464] In some configurations, the auxiliary gases-conveying conduit 305 is positioned outside of the gases-conveying conduit 300 and/or runs parallel to the gases- conveying conduit 300. In some configurations, the auxiliary gases-conveying conduit 305 is in fluid communication at an input end with a flow generator, in other configurations, the auxiliary gases-conveying conduit 305 is in fluid communication at an input end with the gases conveying-conduit 300 with the characteristics of the auxiliary gases-conveying conduit 305 resulting in a different flow at its output from the gases-conveying conduit 300. In some configurations, the auxiliary gases-conveying conduit 305 has its outlet at the first terminal end 131 of the first prong 111, alternatively the auxiliary gases-conveying conduit 305 extends to the second prong 112 and has its output there thus resulting in an asymmetrical flow between the prongs 111, 112.

[00465] Referring to Figure 13, a patient interface 10 having a nasal interface 100 is shown. The arrangement is similar to that described with reference to Figure 1.

[00466] In this configuration, the nasal interface 100 comprises a flow directing element 240 to provide an asymmetrical flow of gases to the first and second prong 111, 112. [00467] The flow directing element 240 is formed at or near the gases inlet 121. The flow directing element 240 is formed as a sub-channel to direct the flow of gases to the first prong 111. The flow directing element 240 directs a gases flow from the gases- conveying conduit 300 into a first prong directed flow 243. Therefore, most of the gases flow from the gases-conveying conduit 300 is directed into the first prong 111 and into the patient's naris.

[00468] In the present configuration, the flow directing element 240 is formed as a curved channel, having an inlet end 246 facing the gases-conveying conduit 300 and an outlet end 247 facing the first terminal end 131 of the first prong 111. The inlet end 246 is positioned in the gases manifold 120 between the gases inlet 121 and the first base 135. The outlet end 247 is positioned in the first prong 111 at or between the first base 135 and the first terminal end 131.

[00469] In some configurations, the inlet end 246 of the flow directing element 240 is positioned in the gases-conveying conduit 300 or in the gases inlet 121. In some configurations, the outlet end 247 of the flow directing element 240 is positioned in the gases manifold 120 and faces the first prong 111 first base 135.

[00470] The flow directing element 240 is positioned to provide a first prong gap 242 between itself and an internal wall of the first prong 111. Therefore, the part of the flow directing element 240 positioned in the first prong 111 (e.g., the outlet end 247) is smaller in an outside dimension than the internal dimension of the first prong 111. The first prong gap 242 provides a first manifold directed flow 245. The first manifold directed flow 245 allows a flow down the first prong 111, i.e. in the first terminal end 131 to first base 135 direction to be partially directed through the first prong gap 242. Therefore, an exhalation gas of a patient that passes into the first prong 111 may, at least, be partially directed through the first prong gap 242 as first manifold directed flow 245 and flows into the gases manifold 120 in the direction of the second prong 112.

[00471] The shape of the flow directing element 240 may be referred to having angled protrusions.

[00472] Turbulent gases flow or flow that interacts with patient exhalation flow that emerges from the outlet end 247 of flow directing element 240 may also be first manifold directed flow 245 before reaching the patient's naris.

[00473] The cross-sectional area of the first prong gap 242 is smaller than the cross- sectional area of the outlet end 247 of the flow directing element 240. However, in some configurations, the cross-sectional area of the first prong gap 242 is larger than the cross- sectional area outlet end 247 of the flow directing element 240.

[00474] In some configurations, the flow directing element 240 is positioned to provide a manifold gap 241 between itself and an internal wall of the gases manifold 120. The manifold gap 241 provides a second manifold directed flow 244. The second manifold directed flow 244 allows a gases flow into the gases manifold 120, i.e. from the gases- conveying conduit 300, to be partially directed through the manifold gap 241. Therefore, a portion of the gases flow into the gases manifold 120, is directed through the manifold gap 241 as second manifold directed flow 244 and flows into the gases manifold 120 in the direction of the second prong 112.

[00475] The cross-sectional area of the manifold gap 241 is smaller than the cross- sectional area of the inlet end 246 of the flow directing element 240. However, in some configurations, the cross-sectional area of the manifold gap 241 is larger than the cross- sectional area of the inlet end 246 of the flow directing element 240.

[00476] The flow directing element 240, therefore, directs all or most of the gases flow from the gases-conveying conduit 300 into the first prong 111 as first prong directed flow 243. The gases flow to the second prong 112 is the first manifold directed flow 245 through the first prong gap 242 and/or second manifold directed flow 244 through the manifold gap 241.

[00477] The flow of gases that reaches the first prong 111 has fewer direction changes as it passes through the flow directing element 240.

[00478] This arrangement results in a larger dynamic pressure at the first prong and a smaller dynamic pressure at the second prong 112. Therefore, an asymmetric flow is provided to the prongs 111, 112.

[00479] Referring to Figure 14, a patient interface 10 having a nasal interface 100 is shown. The arrangement is similar to that described with reference to Figure 1 and has a different configuration for the flow direction element 240 as described with reference to Figure 13.

[00480] In this configuration, the flow directing element 240 provides an asymmetrical flow of gases to the first and second prong 111, 112.

[00481] The flow directing element 240 is formed at or near the gases inlet 121. The flow directing element 240 comprises a first angled protrusion 248 to direct the flow of gases to the first prong 111. The first angled protrusion 248 is formed as a plate or wall. The flow of gases from the gases inlet 121 passes into the flow directing element 240 and the first angled protrusion 248 directs the flow as the first prong directed flow 243 toward the first prong 111. Therefore, flow directing element 240 and the first angled protrusion 248 generally directs the gases flow from the gases-conveying conduit 300 to the first prong 111. The larger dynamic pressure at the first prong 111 compared to the second prong 112 produces an asymmetric flow.

[00482] The first angled protrusion 248 is positioned within the gases manifold 120 near the gases inlet 121. Therefore, the flow directing element 240 and the first angled protrusion 248 may not block or (fully) restrict flow in the manifold chamber 125 but instead relies on directing flow to provide an asymmetrical flow to one of the prongs 111, 112. [00483] The flow to the second prong 112 is provided by the first manifold directed flow 245 such that exhaling from the patient may be directed back down the first prong 111 and may be directed by the opposed side of the first angled protrusion 248. Additionally, some flow may not be fully directed into the first nasal prong 111 from the gases inlet 121 and instead flows into the manifold chamber 125 and to the second prong 112.

[00484] In some configurations, to assist with the directing of flow, the gases inlet 121 is positioned on a wall of the gases manifold 120 approximately opposite to the first prong 111 (or second prong 112, as required). Therefore, the flow directing element 240 and the first angled protrusion 248 are assisted in the directing of flow to the relevant prong 111, 112 by the inlet of the gases into the manifold chamber 125 itself. This may also be referred to as a front-entry inlet 121.

[00485] In some configurations, the flow directing element comprises a second angled protrusion 249. The second angled protrusion 249 assists the first angled protrusion 248 with the directing of flow from a gases inlet 121. The first angled protrusion 248 and second angled protrusion 249 are formed on opposing sides of the gases inlet 121. The first angled protrusion 248 and second angled protrusion 249 may be formed in a shape of a nozzle.

[00486] The flow directing element 240 may be positioned to direct flow to the second prong 112 instead of the first prong 111 to provide an asymmetric flow.

[00487] Referring to Figure 15, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 14 and includes the flow directing element 240.

[00488] In the present configuration, the nasal interface 100 further comprises an additional flow directing element 250 or second flow directing element 250.

[00489] The second flow directing element 250 is arranged within the manifold chamber 125 at or near the first prong 111 entrance, i.e. near the first base 135.

[00490] In addition to the flow directing element 240, the additional flow directing element 250 directs a gases flow from the gases-conveying conduit 300 into the first prong 111. Therefore, the first prong directed flow 243 that passes across the manifold chamber 125 is further encouraged into the first prong 111 by the additional flow directing element 250. This ensures that most of the gases flow from the gases-conveying conduit 300 is directed into the first prong 111 and into the patient's naris and thus provides an asymmetrical flow compared to the second prong 112.

[00491] The additional flow directing element 250 is formed as an angled plate or wall, optionally with a wedge shape, thus forming a further nozzle shape at the entrance of the first prong 111 to direct flow therein. The flow of gases from the gases inlet 121 passes into the flow directing element 240 and is directed as first prong directed flow 243 toward the first prong 111, and the additional flow directing element 250 directs any flow that has diverged into the first prong 111. The larger dynamic pressure at the first prong 111 compared to the second prong 112 produces an asymmetric flow.

[00492] The flow to the second prong 112 is provided by the first manifold directed flow 245 such that exhaling from the patient is directed back down the first prong 111. The additional flow directing element 250 forms a direction channel into the manifold chamber 125 for a first manifold directed flow 245. Therefore, the exhalation flow is more directed into the manifold chamber 125 and thus toward the second prong 112. Additionally, some flow may not be fully directed into the first nasal prong 111 from the gases inlet 121 and instead flows into the manifold chamber 125 and to the second prong 112. The additional flow directing element 250 also directs a portion of this flow as second manifold directed flow 244.

[00493] The additional flow directing element 250 may be positioned to direct flow to the second prong 112 instead of the first prong 111 to provide an asymmetric flow. This may be combined with the flow directing element 240 that is directed to the second prong 112.

[00494] The flow directing element 240 and additional flow directing element 250 may be combined with other configurations discussed herein. For instance, the first prong element 201, second prong element 202, manifold element 203, first inlet element 209 and secondment element 208 may be utilized to further restrict flow. Likewise, multiple gases-conveying conduits 300 may also be used with one or more flow directing elements 240 and additional flow directing elements 250 as required to produce the asymmetrical flow at the prongs 111, 112.

[00495] The flow directing elements 240, 250 as herein described, may be formed as part of gases inlet 121, gases manifold 120 or gases conveying conduit 300. That is to say that the flow directing elements 240, 250 may be formed as walls, parts or features of gases inlet 121, gases manifold 120 or gases conveying conduit 300. Such formation may be as a separate structure that is then otherwise integrated with the gases inlet 121, gases manifold 120 or gases conveying conduit 300, or may be formed together, such as a extrusion or moulding process, or might be part of the overall structure such as a nozzle shape for a gases inlet 121. The term "formed together" may also be taken to mean that the flow directing elements 240, 250 are not removeable or permanently integrated with the gases inlet 121, gases manifold 120 or gases conveying conduit 300.

[00496] Referring to Figure 16, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and, as will readily be understood, can optionally be combined with any disclosure herein without needing any modification of the features described.

[00497] In the present configuration, the first prong 111 and second prong 112 are modified to have different lengths. Therefore, a long first prong Illa is provided where the distance between the first terminal end 131 and the first base 135 is longer than a distance between the second terminal end 132 and the second base 136 of a short second prong 112a.

[00498] By providing the long first prong Illa and the short second prong 112a, the prongs Illa, 112a are modified to have different (relative to one another) internal flow resistances. Therefore, the amount of flow through each prong Illa, 112a is different as the flow of gases has further to travel and therefore, the resultant flows are asymmetric. One approach is to have prongs of different length, noting that flow resistance is also dependent on the length of a flow path.

[00499] In some configurations, the long first prong Illa is lengthened relative to the second prong 112, such that the short second prong 112a is the same length as a second prong 112 as described elsewhere in this document. Alternatively, the short second prong 112a is shortened relative to the first prong 111, such that the long first prong Illa is the same length as a first prong 111 as described elsewhere in this document. However, in other arrangements, both the first and second prongs Illa, 112a have their lengths altered. The change in relative lengths may be varied to provide the required asymmetrical flow.

[00500] The changing of the lengths of the prongs Illa, 112a may assume that the internal diameter is the same. In some configurations, the internal diameter may be different that results in different lengths being required for different prongs Illa, 112a. In infant patent interfaces 10, the effect of prong length is more pronounced as the prongs are smaller both in height and in internal diameter. Therefore, smaller differences in prong length will have a relatively greater influence on the flow resistance and thus asymmetric flow.

[00501] In some configurations, the second prong 112 is relatively longer than a first prong 111. The varying of prong lengths Illa, 112a may be combined with any disclosure herein, for instance, the first prong element 201, second prong element 202, manifold element 203, first inlet element 209 and second inlet element 208 may be utilized to further restrict flow.

[00502] The varied length prongs, e.g. long first prong Illa and short second prong 112a or any variation of length of prongs 111, 112, may be combined with any configuration described herein, such as, in a non-limiting example, with other features that provide an asymmetrical flow.

[00503] Referring to Figure 17, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. As will readily be understood the optional combination with any disclosure herein would not require needing any modification of the features described.

[00504] In the present configuration, the first prong 111 and second prong 112 are modified to have different end geometries. Therefore, a nozzle first prong 111b is provided where the first terminal end 131 is tapered or narrowed at its tip to form a nozzle. A diffuser second prong 112b is provided where the second terminal end 132 is expanded at its tip to form as diffuser.

[00505] In some configurations, one of the nozzle first prong 111b or diffuser second prong 112b is provided.

[00506] By providing the nozzle first prong 111b and diffuser second prong 112b, the prongs 111b, 112b are modified to have different (relative to one another) internal flow resistances. Therefore, the amount of flow through each prong 111b, 112b is different as the flow of gases has a different exit profile as determined by the terminal end 131, 132.

[00507] The nozzle first prong 111b behaves similarly to a nozzle, inducing the flow exiting the nozzle first prong 111b to have a higher velocity and narrow profile compared to an unmodified prong 111, 112. Therefore, a higher gases velocity at one prong will result in asymmetrical flow.

[00508] The diffuser second prong 112b behaves similarly to a diffuser, inducing the flow exiting the diffuser second prong 112b to have a broader profile and lower exit velocity. Therefore, a lower gases velocity at one prong will result in asymmetrical flow.

[00509] Whilst the effect of a diffuser is to result in lower exit velocity, in some configurations, a further effect of the use of the diffuser second prong 112b is that the diffuser ends could occlude a patent's naris where the ends extend to fill the naris. This may result in an increase in resistance to flow. However, this has advantages of resulting in a different flow of gases compared to an unmodified prong 111, 112. Therefore, an asymmetrical flow is formed at the prongs.

[00510] A further advantage of a diffuser second prong 112b is that noise may be attenuated compared to an unmodified prong 111, 112, or the nozzle first prong 111b. The same flow of gases exiting through a larger opening has a lower velocity and thus less sound.

[00511] In some configurations, the nozzle may be provided at the second prong 112 and/or the diffuser may be provided at the first prong 111. The nozzle first prong 111b and diffuser second prong 112b and described herein, may be combined with any other configuration described herein and optionally also with the different length prongs as described with reference to Figure 16.

[00512] Referring to Figure 18, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. It will be understood that no modification of other features is required to combine with the herein described embodiment.

[00513] In the present configuration, the first prong 111 is modified to have internal ridges. Therefore, a ridged first prong 111c is provided where ridges 260 are formed on the inner surface of the ridged first prong 111c. [00514] By the ridged first prong 111c and an unmodified second prong 112, the prongs 111c, 112 have different (relative to one another) internal flow resistances due to different internal surface areas. Therefore, the amount of flow through each prong 111c, 112 is different as the flow of gases is varied, resisted or disrupted in the ridged first prong 111c, and the resultant flows are asymmetric.

[00515] To increase the surface area, the ridges 260 are formed either grooves in the internal surface of the ridged first prong 111c, or as protrusions on the internal surface of the ridged first prong 111c. In some configurations, the ridges 260 are formed by adding material from the ridged first prong 111c, in other configurations, the ridges 260 are formed by removing material from the ridged first prong 111c.

[00516] The ridges 260 may be formed as rings, spirals or strips in a substantially concentric pattern on the interior of the ridged first prong 111c. Any number of ridges 260 may be formed, such as a single ridge 260 or a plurality of ridges 260. The ridges 260 may be equally spaced or have varied spacing. The sizes of the ridges 260, such as protruding size, may be the same for all ridges 260 or may be varied.

[00517] In some configurations, the ridges 260 may be formed in the second prong 112. When formed in the second prong 112, the ridges 260 are either not present in the first prong 111 or the ridged first prong 111c has different ridges 260 to result in a different internal flow resistances to provide an asymmetrical flow at the prong.

[00518] The ridged first prong 111c may be combined with other configurations described herein, and also optionally with configurations such as the different length prongs as described with reference to Figure 16 and/or the nozzle first prong 111b I diffuser second prong 112b as described with reference to Figure 17.

[00519] Referring to Figure 19, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. It will be understood that no modification of other features is required to combine with the herein described embodiment.

[00520] In the present configuration, the first prong 111 is modified to have internal fins 261. Therefore, a finned first prong llld is provided where fins 261 are formed on the inner surface of the finned first prong llld.

[00521] The combination of the finned first prong llld and the unmodified second prong 112, the prongs llld, 112 have different (relative to one another) internal flow resistances due to different internal surface areas. Therefore, the amount of flow through each prong llld, 112 is different as the flow of gases is varied, resisted or disrupted in the finned first prong llld, and the resultant flows are asymmetric.

[00522] To increase the surface area, the fins 261 are formed either grooves in the internal surface of the finned first prong llld, or as protrusions on the internal surface of the finned first prong llld. In some configurations, the fins 261 are formed by adding material from the finned first prong llld, in other configurations, the fins 261 are formed by removing material from the finned first prong llld.

[00523] The fins 261 may be formed as lines, strips or bars in a substantially axial direction pattern the interior of the finned first prong llld. Any number of fins 261 may be formed, such as a fin 261 or a plurality of fins 261. The fins 261 may be equally spaced or have varied spacing. The sizes of the fins 261, such as protruding size, may be the same for all fins 261 or may be varied.

[00524] In some configurations, the fins 261 may be formed in the second prong 112. When formed in the second prong 112, the fins 261 are either not present in the first prong 111 or the finned first prong llld has fins 261 that are configured different, such as a different size, arrangement or number to result in a different internal flow resistances to provide an asymmetrical flow at the prongs.

[00525] The features of the ridges 260 or fins 261 described with reference to Figures 18 and 19 may collectively be referred to as surface features.

[00526] The finned first prong llld may be combined with other configurations as described herein and, optionally, also with configurations such as the different length prongs as described with reference to Figure 16, the nozzle first prong 111b I diffuser second prong 112b as described with reference to Figure 17, or the ridges 260 in either of the first or second prongs 111, 112 as described with reference to Figure 18.

[00527] Referring to Figure 20, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. As will readily be understood the optional combination with any disclosure herein would not require needing any modification of the features described.

[00528] In the present configuration, the first prong 111 is modified to have a noncircular cross-section or a non-circular cross-sectional shape. Therefore, a non-circular first prong llle is provided where the shape of the lumen of the non-circular first prong llle is varied from the shape of a cylinder or substantial cylinder as is the usual shape for a conduit.

[00529] The combination of the non-circular first prong llle and the unmodified second prong 112 result in the prongs llle, 112 having different (relative to one another) internal flow resistances due to different internal surface areas. Therefore, the amount of flow through each prong llle, 112 is different as the flow of gases is varied, resisted or disrupted in the non-circular first prong llle as compared with the substantially circular cross-section of the second prong 112, and the resultant flows are asymmetric.

[00530] To increase or vary the surface area, the profile of the non-circular first prong llle can take various forms. In a non-limiting example, a first profile lllf, when viewed in an axial direction, has a circular profile with an additional smaller diameter circular profile formed on a wall thereof. Therefore, the flow area of the first profile is reduced by the size of the smaller diameter circle. In a further non-limiting example, a second profile Illg, when viewed in an axial direction, has a circular profile with an additional smaller equivalent diameter U-shaped profile formed on a wall therein. The curved part of the U-shape projecting into the centre of the circular profile. Therefore, the flow area of the first profile is reduced by the size of the U-shape of the profile. In a further non-limiting example, a third profile lllh, when viewed in an axial direction, has a triangular profile with curved corners. Therefore, either the flow area of the first profile is varied by the size of the third profile lllh, or the shape of the channel formed by the third profile lllh itself results in a different flow characteristic than a circular profile. In some configurations, any profile may be used that varies from the circular cross-section.

[00531] The non-circular first prong llle may be formed along the length of the prong, or may by partially along the prong, such as at one of or between the first terminal end 131 and first base 135. The sizes and variations of the profile shapes may be varied along the length of the prong.

[00532] In some configurations, the non-circular profiles, such as the first, second or third profile lllf, Illg, lllh may be formed in the second prong 112. When formed in the second prong 112, non-circular first prong llle may be replaced with a non-modified first prong 111 or the non-circular first prong llle has a cross-sectional profile that is different to that of the second prong 112. to result in a different internal flow resistances to provide an asymmetrical flow at the prongs.

[00533] The first profile lllf, second profile Illg and third profile lllh may be orientated in any direction as a nasal prong 111, 112. Therefore, any feature, such as the protruding U-shape of the first profile lllf or second profile Illg or the flat face of a triangle of the third profile lllh may be facing inwards toward the face of a patient, outwards away from the face of a patient or sideways across the face of a patient - or any other orientation.

[00534] In some configurations, a protruding part of the prong profile, such as the U-shape of the first profile lllf or second profile Illg, is used to house an auxiliary tube, such as a nasogastric tube. Such an auxiliary tube may be positioned internal or external to the prong 111, 112.

[00535] In some configurations, the varied profile of the prong 111, 112, such as described with reference to Figure 20, or any other variation in a profile may be present only at a terminal end 131, 132 of the prong 111, 112. Such a profile may include a gap or protrusion to accommodate an auxiliary tube as described elsewhere., Such an auxiliary tube can be provided on an outside or an inside of the prong 111, 112. An auxiliary tube may in itself occlude a nostril increasing a resistance to flow and thus providing an asymmetrical flow at (at least one) of the prongs 111, 112.

[00536] The non-circular first prong llle may be combined with any other configuration described herein and, optionally with configurations such as the different length prongs as described with reference to Figure 16, the nozzle first prong 111b / diffuser second prong 112b as described with reference to Figure 17, the ridges 260 in at least one of the first or second prongs 111, 112 as described with reference to Figure 19, and/or the fins 261 formed in at least one of the first prong 111 or second prongs 112 as described with reference to Figure 20.

[00537] In some configurations, further modifications to the first prong 111 or second prong 112 to modify the surface area or flow therethrough, such as described with reference to Figures 2, 11 or 16 to 20, may be provided in an alternative or additionally to those described herein. In one configuration, at least one of the first prong 111 or second prong 112 has an increased wall thickness relative to the other. The increased wall thickness results in at least of the first prong 111 or second prong 112 having a reduced cross-section flow area and thus less gases flow can pass therethrough. This results in an asymmetrical flow due to the difference in internal flow resistances of the prongs 111, 112. [00538] In a further configuration, at least one of the first prong 111 or second prong 112 has a restriction at the terminal end 131, 132 of the prong 111, 112. The restriction being alternative or additional to the first or second prong elements 201, 202. For instance, in some configurations, the restriction is formed as part of the terminal end 131, 132 of the prong 111, 112 itself, such as having a partial closure formed thereon.

[00539] In a further configuration, at least one of the first prong 111 or second prong 112 has a base restriction 262 at the first or second base 135, 136 of the prong 111, 112. The restriction being alternative or additional to the first or second prong elements 201, 202. An exemplary configuration of a base end restriction 262 is provided in Figure 21. In Figure 21, it is shown that the base end restrictions 262 are formed at the second base 136 of the second prong 112. The base end restrictions 262 are formed as having a flow disrupting entrance to the second prong 112, such as having a flat flow facing surface with sharp edges opening up into the flow channel of the second prong 112. Such an arrangement provides flow disruptions to reduce the gases flow through the base end restriction 262 relative to the first prong 111 without any base end restriction 262. Therefore, asymmetrical flow is provided at the prongs.

[00540] The base end restriction 262 has a flow directing surface for reverse flow through the second prong 112. Therefore, exhalation gases are not restricted in the same manner through the base end restriction 262 to ensure no build-up of pressure at the naris of the patient.

[00541] In some configurations, the base end restriction 262 may be formed in the first prong 111. When formed in the first prong 111, the second prong 112 may be a nonmodified second prong 112 or may have the base end restrictions 262 that provide different flow characteristics. Whilst an example of the base end restriction 262 is provided, other variations are possible. [00542] Referring to Figure 22, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. As will readily be understood the optional combination with any disclosure herein would not require needing any modification of the features described.

[00543] In the present configuration, the first prong 111 is modified to have a valve. Therefore, a valved first prong Illi is provided where a duckbill valve 263 is formed within the valved first prong Illi.

[00544] The duckbill valve 263 is positioned in a direction in the valved first prong Illi to allow a flow of gases to pass from the manifold chamber 125 through the valved first prong Illi to the naris of a patient in varying amounts based on the pressure difference across the duckbill valve 263. In some configurations, the duckbill valve 263 may only allow flow to pass above a defined pressure, after which the gases flow increases based on this pressure difference. To function in this manner, the duckbill valve 263 is in a closed position 265 until a defined pressure is realised at which the duckbill valve 263 begins to open to allow flow. The amount of flow I flow rate causes a pressure difference that further opens the duckbill valve 263 until it reaches a fully open position 264. Alternatively, the duckbill valve 263 only allows flow to pass through with a low-pressure differential and the flow varies as a function of this pressure differential increasing flow as the pressure difference increases. The duckbill valve 263 acts as a one-way valve preventing a backflow of gases flow from the patient. Therefore, a greater pressure difference between the first terminal end 131 of the valved first prong Illi and the first base 135 of the valved first prong Illi forces the duckbill valve 263 to the closed position 265. In this regard, the valved first prong Illi is a non-sealing prong to ensure no buildup of pressure in the naris of a patient. The pressure requirements to allow flow through the valved first prong Illi and duckbill valve 263 results in an asymmetrical flow relative to an unmodified second prong 112.

[00545] In some configurations, the duckbill valve 263 may be formed in the second prong 112. When formed in the second prong 112, the first prong 111 may be a nonmodified first prong 111 or may have the duckbill valve 263 configured to result in different flow characteristics. Whilst an example of a duckbill valve 263 is provided, other valves are also usable.

[00546] The duckbill valve 263 may be combined with any other configuration described here.

[00547] In some configurations, at least one of the first prong 111 or second prong 112 is angled with reference to a midline plane of the nasal interface 100, optionally with reference to the patient's nasal septum when in use. Therefore, the axis of the first prong 111 may be at a different relative angle (reference to the midline plane of the nasal interface 100) to the axis of the second prong 112. For example, one prong 111, 112 may be unmodified whereas the other prong 111, 112 is angled 'outwards', e.g. toward the proximal wall of the gases manifold 120 (or away from the opposing prong 111, 112), such that the prong 111, 112 abuts the nostril wall. Gases flow exiting the angled prong 111, 112 may encounter resistance from the nostril wall and results in different pressures at each prong terminal end 131, 132, thereby inducing asymmetric flow.

[00548] In some configurations, at least one of the first prong 111 or second prong 112 is angled 'inwards', e.g. toward the opposing prong 111, 112. This may result in a less restricted flow depending on the degree of angle.

[00549] Referring to Figure 23, a patient interface 10 having a nasal interface 100 is shown. The arrangement is as that described with reference to Figure 1 and can be combined with any disclosure herein. As will readily be understood the optional combination with any disclosure herein would not require needing any modification of the features described.

[00550] In the present configuration, the nasal interface 100 comprises the first and second nasal prongs 111, 112 and a third nasal prong 115. The third nasal prong 115 is formed in the same manner as either the first or second nasal prongs 111, 112 112 having a flow passage to allow the flow of gases therethrough.

[00551] In addition to the first nasal prong 111 and the second nasal prong 112, the third nasal prong is also in fluid communication with the gases inlet 121 through the manifold 120. The gases inlet 121 is positioned at the manifold 120 such that the first nasal prong 111 is more proximal to the gases inlet 121 and the third nasal prong 115 is more distal to the gases inlet 121 with the second nasal prong 112 positioned therebetween.

[00552] The first, second and third nasal prongs 111, 112, 115 are spaced apart to be engageable into the nares of a patient as adjacent pairs. Therefore, the first and second prongs 111, 112 may be engaged as described with the two prong 111, 112 configurations described elsewhere in this disclosure, or the second and third prongs 112, 115 may be engaged with the nares of a patient.

[00553] Therefore, the nasal interface 100 of this configuration when in use has either the first prong 111 or third prong 115 unengaged and open to atmosphere. To avoid the loss of pressure and gases flow within the gases manifold through the engaged prong 111, 115, a closure 119 is releasably engageable within the unused prong 111, 115. Therefore, the nasal interface 100 is reconfigurable by moving of the closure 119 between a first configuration where the first 111 and second 112 prongs allow the passage of gases to a patient's nares and a second configuration where the second 112 and third 115 prongs allow the passage of gases to a patient's nares. The closure 119 being engaged to prevent a flow of gases through the third prong 115 or the first prong 111 between the first and second configuration respectively.

[00554] The closure 119 could be any suitable form, such as a plug or cap for example. Furthermore, in some configurations, the closure 119 is engageable by a further part of nasal interface 100. For instance, the inlet 121 or gases-conveying conduit 300 is insertable into the gases manifold 120 to block at least one of the prongs 111, 112, 115. Therefore, the flow is provided to the unblocked prongs 111, 112, 115. In such a configuration, the closure 119 is formed at the base of the prong 111, 112, 115. The closure 119 may be moveable by inserting, for instance, the gases-conveying conduit 300 into an opposite side of the gases manifold 120, such as where there is a second inlet 122. Therefore, the prong proximal to the respective inlet 121, 122 is blocked by the gases- conveying conduit 300. Alternatively, the closure 119 is formed by the distance that the gases-conveying conduit 300 is inserted into the gases manifold 120, such by having openings in the conduit that align with prong openings or openings within the gases manifold 120 at different locations. Other parts of the nasal interface 10 may be reconfigurable to result in the closure of at least one prong 111, 112, 115 as herein described.

[00555] The first, second and third prongs 111, 112, 115 are configured to have different gases flows therethrough to result in an asymmetrical flow as described throughout this document. Therefore, as non-limiting examples, at least one of the first, second or third prongs 111, 112, 115 have a flow restriction in the form of the first prong element 201, second prong element 202, manifold element 203, first inlet element 209 and secondment element 208, flow directing elements 240, additional flow directing elements 250, different length prongs as described with reference to Figure 16, the nozzle and diffusers as described with reference to Figure 17, the ridges 260 as described with reference to Figure 19, fins 261 as described with reference to Figure 20, base end restrictions 262 as described with reference to Figure 21, or a duckbill valve 263 as described with reference to Figure 22. Furthermore, in some configurations, a second inlet 122, such as described with reference to Figure 9 is combined with the first, second and third prongs 111, 112, 115 to allow a gases flow at either side of the gases manifold 120. This provides additional control for asymmetrical flow.

[00556] The flow restriction of at least one of the first, second and third prongs 111, 112, 115 allows the user to move their nostrils between engagement in with the first and second prongs 111, 112 to engagement with the second and third prongs 112, 115 to have differently configured asymmetrical flow.

[00557] In some configurations, the first and third prongs 111, 115 are configured to have the same gases flow therethrough, and the second prong 112 is configured to have a different gases flow therethrough, to allow the asymmetrical flow to be switched between a left and a right nostril. Therefore, a larger dynamic pressure is provided at the second prong 112 and a smaller dynamic pressure is provided at the first and third prongs 111, 115, or larger dynamic pressure at the first and third prongs 111, 115 and a smaller dynamic pressure is provided at a second prong 112. [00558] In an alternative configuration, the first and second prongs 111, 112 are modular to allow the removal and replacement of prong types with varying flow restrictions.

[00559] Patient interfaces 10 with nasal interfaces 100 according to the configurations described herein may be employed in a method of delivering gas to the airway of a patient in need thereof, improving the ventilation of a patient in need thereof, reducing the volume of anatomical dead space within the volume of the airway of a patient in need thereof, and/or treating a respiratory condition in a patient in need thereof, as described above.

[00560] Patient interfaces 10 comprising nasal interfaces 100 of the type disclosed herein may be used in a respiratory therapy system for delivering gases to a patient.

[00561] In some configurations, the respiratory therapy system 1000 comprises a respiratory therapy apparatus 1100 and a patient interface comprising 10 a nasal interface 100.

[00562] An exemplary respiratory therapy apparatus 1100 is shown in Figure 24.

[00563] The respiratory therapy apparatus 1100 comprises a main housing 1101 that contains a flow generator 1011 in the form of a motor/impeller arrangement (for example, a blower), an optional humidifier 1012, a controller 1013, and a user interface 1014 (comprising, for example, a display and input device(s) such as button(s), a touch screen, or the like).

[00564] The controller 1013 can be configured or programmed to control the operation of the apparatus. For example, the controller can control components of the apparatus, including but not limited to: operating the flow generator 1011 to create a flow of gas (gases flow) for delivery to a patient, operating the humidifier 1012 (if present) to humidify and/or heat the generated gases flow, control a flow of oxygen into the flow generator blower, receiving user input from the user interface 1014 for reconfiguration and/or user-defined operation of the apparatus 1000, and outputting information (for example on the display) to the user.

[00565] The user can be a patient, healthcare professional, or anyone else interested in using the apparatus. As used herein, a "gases flow" can refer to any flow of gases that may be used in the breathing assistance or respiratory device, such as a flow of ambient air, a flow comprising substantially 100% oxygen, a flow comprising some combination of ambient air and oxygen, and/or the like.

[00566] A patient breathing conduit 300 is coupled at one end to a gases flow outlet 1021 in the housing 1100 of the respiratory therapy apparatus 1100. The patient breathing conduit 300 is coupled at another end to the nasal interface 100 with the gases manifold 120 and nasal prongs 111, 112.

[00567] The gases flow that is generated by the respiratory therapy apparatus 1100 may be humidified, and delivered to the patient via the patient conduit 300 through the nasal interface 100. The patient conduit 300 can have a heater to heat gases flow passing through to the patient. For example, the patient conduit 300 can have a heater wire 300a to heat gases flow passing through to the patient. The heater wire 300a can be under the control of the controller 1013. The patient conduit 300 and/or nasal interface 100 can be considered part of the respiratory therapy apparatus 1100, or alternatively peripheral to it. The respiratory therapy apparatus 1100, breathing conduit 300, and patient interface 10 comprising a nasal interface 100 together can form a respiratory therapy system 1000. [00568] The controller 1013 can control the flow generator 1011 to generate a gases flow of the desired flow rate. The controller 1013 can also control a supplemental oxygen inlet to allow for delivery of supplemental oxygen, the humidifier 1012 (if present) can humidify the gases flow and/or heat the gases flow to an appropriate level, and/or the like. The gases flow is directed out through the patient conduit 300 and nasal interface 100 to the patient. The controller 1013 can also control a heating element in the humidifier 1012 and/or the heating element 300a in the gases-conveying conduit 300 to heat the gas to a desired temperature for a desired level of therapy and/or level of comfort for the patient. The controller 1013 can be programmed with or can determine a suitable target temperature of the gases flow. In some configurations, gas mixture compositions including supplemental oxygen and/or administration of therapeutic medicaments may be provided through the supplemental oxygen inlet. The gas mixtures compositions may comprise oxygen, heliox, nitrogen, nitric oxide, carbon dioxide, argon, helium, methane, sulfur hexafluoride, and combinations thereof, and/or the supplemental gas can comprise an aerosolized medicament.

[00569] The oxygen inlet port 1028 can include a valve 1028a through which a pressurized gas may enter the flow generator or blower. The valve can control a flow of oxygen into the flow generator blower. The valve can be any type of valve, including a proportional valve or a binary valve. The source of oxygen can be an oxygen tank or a hospital oxygen supply. Medical grade oxygen is typically between 95% and 100% purity. Oxygen sources of lower purity can also be used. Examples of valve modules and filters are disclosed in PCT publication number WO 2018/074935 and US patent application publication no. 2019/0255276, both titled "Valve Module and Filter. The contents of those specifications are incorporated herein in their entireties by way of reference.

[00570] The respiratory therapy apparatus 1100 can measure and control the oxygen content of the gas being delivered to the patient, and therefore the oxygen content of the gas inspired by the patient. During high flow therapy, the high flow rate of gas delivered may meet or exceed the peak inspiratory flow of the patient. This means that the volume of gas delivered by the device to the patient during inspiration meets, or is in excess of, the volume of gas inspired by the patient during inspiration. High flow therapy therefore helps to prevent entrainment of ambient air when the patient breathes in, as well as flushing the patient's airways of expired gas. If the flow rate of delivered gas meets or exceeds peak inspiratory flow of the patient, entrainment of ambient air may be prevented, and the gas delivered by the device is substantially the same as the gas the patient breathes in. As such, the oxygen concentration measured in the device, fraction of delivered oxygen, (FdO2) would be substantially the same as the oxygen concentration the user is breathing, fraction of inspired oxygen (FiO2), and as such the terms may can be seen as equivalent.

[00571] Operation sensors 1003a, 1003b, 1003c, such as flow, temperature, humidity, and/or pressure sensors can be placed in various locations in the respiratory therapy apparatus 1100. Additional sensors (for example, sensors 1020, 1025) may be placed in various locations on the patient conduit 300 and/or nasal interface 100 (for example, there may be a temperature sensor 1029 at or near the end of the inspiratory tube). Output from the sensors can be received by the controller 1013, to assist the controller in operating the respiratory therapy apparatus 1100 in a manner that provides suitable therapy. In some configurations, providing suitable therapy includes meeting a patient's peak inspiratory flow. The apparatus 1100 may have a transmitter and/or receiver 1015 to enable the controller 1013 to receive signals 1008 from the sensors and/or to control the various components of the respiratory therapy apparatus 1100, including but not limited to the flow generator 1011, humidifier 1012, and heater wire 300a, or accessories or peripherals associated with the respiratory therapy apparatus 1100. Additionally, or alternatively, the transmitter and/or receiver 1015 may deliver data to a remote server or enable remote control of the apparatus 1100.

[00572] Oxygen may be measured by placing one or more gas composition sensors (such as an ultrasonic transducer system, also referred to as an ultrasonic sensor system) after the oxygen and ambient air have finished mixing. The measurement can be taken within the device, the delivery conduit, the patient interface, or at any other suitable location.

[00573] The respiratory therapy apparatus 1100 can include a patient sensor 1026, such as a pulse oximeter or a patient monitoring system, to measure one or more physiological parameters of the patient, such as a patient's blood oxygen saturation (SpO2), heart rate, respiratory rate, perfusion index, and provide a measure of signal quality.

[00574] The sensor 1026 can communicate with the controller 1013 through a wired connection or by communication through a wireless transmitter on the sensor 1026.

[00575] The sensor 1026 may be a disposable adhesive sensor designed to be connected to a patient's finger. The sensor 1026 may be a non-disposable sensor.

[00576] Sensors are available that are designed for different age groups and to be connected to different locations on the patient, which can be used with the respiratory therapy apparatus 1100. [00577] The pulse oximeter would be attached to the user, typically at their finger, although other places such as an earlobe are also an option. The pulse oximeter would be connected to a processor in the device and would constantly provide signals indicative of the patient's blood oxygen saturation. The patient sensor 1026 can be a hot swappable device, which can be attached or interchanged during operation of the respiratory therapy apparatus 1100. For example, the patient sensor 1026 may connect to the respiratory therapy apparatus 1100 using a USB interface or using wireless communication protocols (such as, for example, near field communication, WiFi or Bluetooth®). When the patient sensor 1026 is disconnected during operation, the respiratory therapy apparatus 1100 may continue to operate in its previous state of operation for a defined time period. After the defined time period, the respiratory therapy apparatus 1100 may trigger an alarm, transition from automatic mode to manual mode, and/or exit control mode (e.g., automatic mode or manual mode) entirely. The patient sensor 1026 may be a bedside monitoring system or other patient monitoring system that communicates with the respiratory therapy apparatus 1100 through a physical or wireless interface.

[00578] The respiratory therapy apparatus 1100 may comprise a high flow therapy apparatus. High flow therapy as discussed herein is intended to be given its typical ordinary meaning as understood by a person of skill in the art, which generally refers to a respiratory assistance system delivering a targeted flow of humidified respiratory gases via an intentionally unsealed patient interface with flow rates generally intended to meet or exceed inspiratory flow of a patient. Typical patient interfaces include, but are not limited to, a nasal or tracheal patient interface. Typical flow rates for adults often range from, but are not limited to, about fifteen liters per minute (Ipm) to about seventy liters per minute or greater. Typical flow rates for pediatric patients (such as neonates, infants and children) often range from, but are not limited to, about one liter per minute per kilogram of patient weight to about three liters per minute per kilogram of patient weight or greater. High flow therapy can also optionally include gas mixture compositions including supplemental oxygen and/or administration of therapeutic medicaments. High flow therapy is often referred to as nasal high flow (NHF), humidified high flow nasal cannula (HHFNC), high flow nasal oxygen (HFNO), high flow therapy (HFT), or tracheal high flow (THF), among other common names. The flow rates used to achieve "high flow" may be any of the flow rates listed below. For example, in some configurations, for an adult patient 'high flow therapy' may refer to the delivery of gases to a patient at a flow rate of greater than or equal to about 10 liters per minute (10 Ipm), such as between about 10 Ipm and about 100 Ipm, or between about 15 Ipm and about 95 Ipm, or between about 20 Ipm and about 90 Ipm, or between 25 Ipm and 75 Ipm, or between about 25 Ipm and about 85 Ipm, or between about 30 Ipm and about 80 Ipm, or between about 35 Ipm and about 75 Ipm, or between about 40 Ipm and about 70 Ipm, or between about 45 Ipm and about 65 Ipm, or between about 50 Ipm and about 60 Ipm. In some configurations, for a neonatal, infant, or child patient 'high flow therapy' may refer to the delivery of gases to a patient at a flow rate of greater than 1 Ipm, such as between about 1 Ipm and about 25 Ipm, or between about 2 Ipm and about 25 Ipm, or between about 2 Ipm and about 5 Ipm, or between about 5 Ipm and about 25 Ipm, or between about 5 Ipm and about 10 Ipm, or between about 10 Ipm and about 25 Ipm, or between about 10 Ipm and about 20 Ipm, or between about 10 Ipm and 15 Ipm, or between about 20 Ipm and 25 Ipm. A high flow therapy apparatus with an adult patient, a neonatal, infant, or child patient, may deliver gases to the patient at a flow rate of between about 1 Ipm and about 100 Ipm, or at a flow rate in any of the subranges outlined above. The flow therapy apparatus 1000 can deliver any concentration of oxygen (e.g., FdO2), up to 100%, at any flow rate between about 1 Ipm and about 100 Ipm. In some configurations, any of the flow rates can be in combination with oxygen concentrations (FdO2s) of about 20%-30%, 21%-30%, 21%-40%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, and 90%-100%. In some combinations, the flow rate can be between about 25 Ipm and 75 Ipm in combination with an oxygen concentration (FdO2) of about 20%-30%, 21%-30%, 21%-40%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, and 90%-100%. In some configurations, the respiratory therapy apparatus 1100 may include safety thresholds when operating in manual mode that prevent a user from delivering to much oxygen to the patient.

[00579] In some configurations, the respiratory therapy apparatus 1100 comprises a controller 1013; a blood oxygen saturation sensor 1026; an ambient air inlet 1027; an oxygen inlet 1028; a valve 1028a in fluid communication with the oxygen inlet 1028 to control a flow of oxygen through the oxygen inlet 1028; and a gases outlet 1021; wherein the controller 1013 is configured to control the valve 1028a based on at least one measurement of oxygen saturation from the blood oxygen saturation sensor 1026.

[00580] The patient interface 10 used in the respiratory therapy system 1000 with the respiratory therapy apparatus 1100 comprises a nasal interface 100 comprising: a first prong 111 and a second prong 112 that are asymmetrical to each other; and a gases manifold 120 comprising a gases inlet 121, wherein the first prong 111 and the second prong 112 are in fluid communication with the gases inlet 121. The nasal interface 100 is configured to cause an asymmetrical flow of gases at a patient's nares.

[00581] The first prong 111 and the second prong 112 are asymmetrical to each other or are not symmetrical to each other or differ in shape and configuration to each other or are asymmetrical when compared to each other.

[00582] In some configurations, the nasal interface 100 comprises a interface body 118 comprising the first prong 111 and the second prong 112.

[00583] In some configurations, the gases manifold 120 is integral with the interface body 118 or is separate from and couplable with the interface body 118.

[00584] In some configurations, the first and second prongs 111, 112 are configured to engage with the nasal passages in an unsealed manner. [00585] In some configurations, the first and second prongs 111, 112 allow exhaled gases to escape around the first and second prongs.

[00586] In some configurations, the first and second prongs 111, 112 are configured to provide gases to the patient without interfering with the patient's spontaneous respiration.

[00587] The nasal interface 100 may have any one or more of the features and/or functionality described herein for nasal interfaces 100.

[00588] In some configurations, the respiratory therapy apparatus 1000 comprises a flow generator 1011 and a humidifier 1012.

[00589] In some configurations, the respiratory therapy system comprises a patient conduit 300 with a heater 300a.

[00590] In some configurations, the patient interface comprises a breathable tube that is in fluid communication with the gases inlet 121, and the patient interface further comprises a headgear to retain the nasal interface against a patient's face.

[00591] Patients suffering from various health conditions and diseases can benefit from oxygen therapy. For example, patients suffering from chronic obstructive pulmonary disease (COPD), pneumonia, asthma, bronchopulmonary dysplasia, heart failure, cystic fibrosis, sleep apnea, lung disease, trauma to the respiratory system, acute respiratory distress, receiving pre- and post- operative oxygen delivery, and other conditions or diseases can benefit from oxygen therapy. A common way of treating such problems is by supplying the patients with supplemental oxygen to prevent their blood oxygen saturation (SpO2) from dropping too low (e.g., below about 90%). However, supplying the patient with too much oxygen can over oxygenate their blood, and is also considered dangerous. Generally, the patient's SpO2 is kept in a range from about 80% to about 99%, and preferably about 92% to about 96%, although these ranges may differ due to patient conditions. Due to various factors such as respiratory rate, lung tidal volume, heart rate, activity levels, height, weight, age, gender, and other factors, there is no one prescribed level of supplemental oxygen that can consistently achieve an SpO2 response in the targeted range for each patient. Individual patients will regularly need their fraction of oxygen delivered to the patient (FdO2) monitored and adjusted to ensure they are receiving the correct FdO2 to achieve the targeted SpO2. Achieving a correct and consistent SpO2 is an important factor in treating patients with various health conditions or diseases. Additionally, patients suffering from these health problems may find benefit from a system that automatically controls oxygen saturation. The present disclosure is applicable to a wide range of patients that require fast and accurate oxygen saturation control.

[00592] With reference to Figure 24, the controller 1013 can be programmed with or configured to execute a closed loop control system for controlling the operation of the respiratory therapy apparatus 1100. The closed loop control system can be configured to ensure the patient's SpO2 reaches a target level and consistently remains at or near this level.

[00593] The controller 1013 can receive input(s) from a user that can be used by the controller 1013 to execute the closed loop control system. The target SpO2 value can be a single value or a range of values. The value(s) could be pre-set, chosen by a clinician, or determined based on the type of patient, where type of patient could refer to current affliction, and/or information about the patient such as age, weight, height, gender, and other patient characteristics. Similarly, the target SpO2 could be two values, each selected in any way described above. The two values would represent a range of acceptable values for the patient's SpO2. The controller can target a value within said range. The targeted value could be the middle value of the range, or any other value within the range, which could be pre-set or selected by a user. Alternatively, the range could be automatically set based on the targeted value of SpO2. The controller can be configured to have one or more set responses when the patient's SpO2 value moves outside of the range. The responses may include alarming, changing to manual control of FdO2, changing the FdO2 to a specific value, and/or other responses. The controller can have one or more ranges, where one or more different responses occur as it moves outside of each range.

[00594] Generally, SpO2 would be controlled between about 80% and about 100%, or about 80% and about 90%, or about 88% and about 92%, or about 90% and about 99%, or about 92% and about 96%. The SpO2 could be controlled between any two suitable values from any two of the aforementioned ranges. The target SpO2 could be between about 80% and about 100%, or between about 80% and about 90%, or between about 88% and about 92%, or between about 90% and about 99%, or between about 92% and about 96%, or about 94%, or 94% or about 90%, or 90%, or about 85%, or 85%. The SpO2 target could be any value between any two suitable values from any two of the aforementioned ranges. The SpO2 target can correspond to the middle of the SpO2 for a defined range.

[00595] The FdO2 can be configured to be controlled within a range. The oxygen concentration measured in the apparatus (FdO2) may be substantially the same as the oxygen concentration the patient is breathing (FiO2) if the flow rate meets or exceeds the peak inspiratory flow of the patient, and as such the terms may can be seen as equivalent. Each of the limits of the range could be pre-set, selected by a user, or determined based on the type of patient, where the type of patient could refer to current affliction, and/or information about the patient such as age, weight, height, gender, and/or other patient characteristic. Alternatively, a single value for FdO2 could be selected, and the range could be determined at least partially based on this value. For example, the range could be a set amount above and below the selected FdO2. The selected FdO2 could be used as the starting point for the controller. The system could have one or more responses if the controller tries to move the FdO2 outside of the range. These responses could include alarming, preventing the FdO2 moving outside of the range, switching to manual control of FdO2, and/or switching to a specific FdO2. The device could have one or more ranges where one or more different responses occur as it reaches the limit of each range.

[00596] With reference to Figure 25, a schematic diagram of the closed loop control system 1500 is illustrated. The closed loop control system may utilize two control loops. The first control loop may be implemented by the SpO2 controller. The SpO2 controller can determine a target FdO2 based in part on the target SpO2 and/or the measured SpO2. As discussed above, the target SpO2 value can be a single value or a range of acceptable values. The value(s) could be pre-set, chosen by a clinician, or determined automatically based on client characteristics. Generally, target SpO2 values are received or determined before or at the beginning of a therapy session, though target SpO2 values may be received at any time during the therapy session. During a therapy session, the SpO2 controller can also receive as inputs: measured FdO2 reading(s) from a gases composition sensor, and measured SpO2 reading(s) and a signal quality reading(s) from the patient sensor. In some configurations, the SpO2 controller can receive target FdO2 as an input, in such a case, the output of the SpO2 controller may be provided directly back to the SpO2 controller as the input. Based at least in part on the inputs, the SpO2 controller can output a target FdO2 to the second control loop.

[00597] During the therapy session, the SpO2 and FdO2 controllers can continue to automatically control the operation of the respiratory therapy apparatus 1100 until the therapy session ends or an event triggers a change from the automatic mode to manual mode.

[00598] The increase in flushing caused by the asymmetry of the prongs 111, 112 in the nasal interface 100 can improve the effectiveness of the supplemental oxygen. Closed loop SpO2 control with an asymmetric nasal interface 100 can allow for the patient's SpO2 to be maintained at or near a target value with a reduced amount of oxygen being used when compared with symmetric nasal high flow. This can result in oxygen conservation. [00599] The respiratory therapy system may have any one or more of the features and functionality described in PCT publication no. WO 2021/049954 and U.S. provisional application no. 62/898,464. The contents of those specifications are incorporated herein in their entireties by way of reference.

[00600] Figure 26 shows an alternative exemplary respiratory therapy system 2000 that can make use of the patient interface 10 comprising a nasal interface 100.

[00601] In the illustrated configuration, the respiratory therapy system 2000 comprises a respiratory therapy apparatus 2100. The respiratory therapy apparatus may comprise a flow generator 2101.

[00602] The illustrated flow generator 2101 comprises a gases inlet 2102 and a gases outlet 2104. The flow generator 2101 may comprise a blower 2106. The blower 2106 can draw in gas from the gases inlet 2102. In some configurations, the flow generator 2101 can comprise a source or container of compressed gas (e.g., air, oxygen, etc.). The container can comprise a valve that can be adjusted to control the flow of gas leaving the container. In some configurations, the flow generator 2101 can use such a source of compressed gas and/or another gas source in lieu of the blower 2106. In some configurations, the blower 2106 can be used in conjunction with another gas source. In some configurations, the blower 2106 can comprise a motorized blower or can comprise a bellows arrangement or some other structure capable of generating a gas flow. In some configurations, the flow generator 2101 draws in atmospheric gases through the gases inlet 2102. In some configurations, the flow generator 2101 is adapted both to draw in atmospheric gases through the gases inlet 2102 and to accept other gases (e.g., oxygen, nitric oxide, carbon dioxide, etc.) through the same gases inlet 2102 or a different gases inlet. Other configurations also are possible.

[00603] The illustrated flow generator 2101 comprises a user control interface 2108. The user control interface 2108 can comprise one or more buttons, knobs, dials, switches, levers, touch screens, speakers, displays, and/or other input or output modules that a user might use to input commands into the flow generator 2101, to view data, and/or to control operations of the flow generator 2101, and/or to control operations of other aspects of the respiratory therapy system 2000.

[00604] The flow generator 2101 can direct gases through the gases outlet 2104 to a first conduit 2110. In the illustrated configuration, the first conduit 2110 channels the gases to a gas humidifier 2112. The gas humidifier is optional.

[00605] The gas humidifier 2112 is used to entrain moisture in the gases in order to provide a humidified gas stream. The illustrated gas humidifier 2112 comprises a humidifier inlet 2116 and a humidifier outlet 2118. The gas humidifier 2112 can comprise, be configured to contain or contain water or another humidifying or moisturizing agent (hereinafter referred to as water).

[00606] In some configurations, the gas humidifier 2112 comprises a heating element (not shown). The heating element can be used to heat the water in the gas humidifier 2112 to encourage water vaporization and/or entrainment in the gas flow and/or increase the temperature of gases passing through the gas humidifier 2112. The heating element can, for example, comprise a resistive metallic heating plate. However, other heating elements are contemplated. For example, the heating element could comprise a plastic electrically conductive heating plate or a chemical heating system having a controllable heat output.

[00607] In the illustrated configuration, the gas humidifier 2112 comprises a user control interface 2120. The user control interface 2120 comprises one or more buttons, knobs, dials, switches, levers, touch screens, speakers, displays and/or other input or output modules that a user might use to input commands into the gas humidifier 2112, to view data, and/or to control operations of the gas humidifier 2112, and/or control operations of other aspects of the respiratory therapy system 2000.

[00608] In some configurations, the flow generator 2101 and the gas humidifier 2112 may share a housing 2126. In some configurations, the gas humidifier 2112 may share only part of the housing 2126 with the flow generator 2101. Other configurations also are possible.

[00609] In the illustrated configuration, gases travel from the humidifier outlet 2118 to a second conduit 300. The second conduit 300 can comprise a conduit heater as described in relation to Figure 24. The conduit heater can be used to add heat to gases passing through the second conduit 300. The heat can reduce or eliminate the likelihood of condensation of water entrained in the gas stream along a wall of the second conduit 300. The conduit heater can comprise one or more resistive wires located in, on, around or near a wall of the second conduit 300. In one or more configuration, such one or more resistive wires can be located outside of any gas passage. In one or more configurations, such one or more resistive wires are not in direct contact with the gases passing through the second conduit 300. In one or more configurations, a wall or surface of the second conduit 300 intercedes between the one or more resistive wires and the gases passing through the second conduit 300.

[00610] Gases passing through the second conduit 300 can be delivered to a nasal interface 100. The nasal interface 100 can pneumatically link the respiratory therapy system 100 to an airway of a patient. In some configurations, the respiratory therapy system 2000 utilizes a two-limb system comprising separate inspiratory and expiratory gas passageways that interface with one or more airways of the patient.

[00611] In some configurations, a short length of tubing connects the nasal interface 100 to the second conduit 300. In some configurations, the short length of tubing can have a smooth bore. For example, a short flexible length of tubing can connect the nasal interface to the second conduit 300. The short length of tubing connecting the nasal interface to the second conduit 300 may be breathable such that it allows the transmission of vapour through the wall of the tube. In some configurations, the short length of tubing can incorporate one or more heating wires as described elsewhere herein. The smooth bore, whether heated or not, can improve the efficiency in delivering nebulized substances, as described elsewhere herein.

[00612] The respiratory therapy apparatus 2100 comprises a nebulizer 2128. In some configurations, if a nebulizer 2128 is used, the flow generator 2101, the gas humidifier 2112, and the nebulizer 2128 can share the housing 2126. In some configurations, the nebulizer 2128 is separate of the housing 2126.

[00613] The nebulizer 2128 can be linked to a portion of the gas passageway extending between the flow generator 2101 (which may include the gas inlet 2102) and the nasal interface 100, although other arrangements for the nebulizer 2128 or another nebulizer may be utilized. In some configurations, the nebulizer 2128 is not positioned inline in any location between the humidifier outlet 2118 and the nasal interface 100. Rather, the nebulizer 2128 is positioned upstream of the humidifier outlet 2118 or upstream of the inlet to the second conduit 2122. In some configurations, the nebulizer 2128 can be positioned upstream of an inlet into the humidifier. In some configurations, the nebulizer 2128 can be positioned between the source of gases flow and the chamber.

[00614] The nebulizer 2128 can comprise a substance (e.g., a medicinal substance, trace gases, etc.) that can be introduced into the gas flow. The substance can be caught up in the gas flow and can be delivered along with respiratory gases to an airway of the patient. The nebulizer 2128 can be linked to the portion of the gas passageway by a conveyor 2130, which can comprise a conduit or an adaptor. Alternatively, the nebulizer 2128 can interface directly with the gas passageway, which can render the conveyor 2130 unnecessary.

[00615] The respiratory therapy apparatus 2100 may comprise a controller 2113. The controller 2113 can be configured or programmed to control the operation of the apparatus. For example, the controller 2113 can control components of the apparatus, including but not limited to: operating the flow generator 2101 to create a flow of gas (gases flow) for delivery to a patient, operating the humidifier 2112 (if present) to humidify and/or heat the generated gases flow, control a flow of oxygen into the flow generator blower, receiving user input from the user interface 2108 and/or 2120 for reconfiguration and/or user-defined operation of the apparatus 2100, and outputting information (for example on a display) to the user.

[00616] The controller 2113 can control the flow generator 2101 to generate a gases flow of the desired flow rate. The controller 2113 can also control a supplemental oxygen inlet to allow for delivery of supplemental oxygen, the humidifier 2112 (if present) can humidify the gases flow and/or heat the gases flow to an appropriate level, and/or the like. The controller 2113 may also the operation of the nebulizer 2128. The gases flow is directed out through the patient conduit 300 and nasal interface 100 to the patient. The controller 2113 can also control a heating element in the humidifier 2112 and/or a heating element in the patient conduit 300 to heat the gas to a desired temperature for a desired level of therapy and/or level of comfort for the patient. The controller 2113 can be programmed with or can determine a suitable target temperature of the gases flow. In some configurations, gas mixture compositions including supplemental oxygen and/or administration of therapeutic medicaments may be provided through the supplemental oxygen inlet. The gas mixtures compositions may comprise oxygen, heliox, nitrogen, nitric oxide, carbon dioxide, argon, helium, methane, sulfur hexafluoride, and combinations thereof, and/or the supplemental gas can comprise an aerosolized medicament from the nebulizer 2128. [00617] In some configurations, the respiratory therapy apparatus 2100 comprises a gases inlet 2102, a gases outlet 2118, and a nebulizer 2128 to deliver one or more substances into a gases flow. The nasal interface 100 used in the respiratory therapy system 2000 with the respiratory therapy apparatus 2100 comprises: a gases inlet 121 in fluid communication with the gases outlet 2118 to receive gases and the one or more substances from the respiratory therapy apparatus; a first prong 111 and a second prong 112; and a gases manifold 120 comprising a gases inlet 121. The first prong 111 and second prong 112 are in fluid communication with the gases inlet 121. The nasal interface 100 is configured to cause an asymmetrical flow of gases at a patient's nares.

[00618] The respiratory therapy system 2000 may comprise a conduit 300, 320 (examples of which are described below) to receive the gases and the one or more substances from the respiratory therapy apparatus 2100 and deliver the gases and the one or more substances to the gases inlet 121 of the nasal interface 100.

[00619] In the illustrated configuration, the respiratory therapy system 2000 can operate as follows. Gases can be drawn into the flow generator 2101 through the gas inlet 2102 due to the rotation of an impeller of the motor of the blower 2106. The gases are propelled out of the gas outlet 2104 and through the first conduit 2110. The gases enter the gas humidifier 2112 through the humidifier inlet 2116. Once in the gas humidifier 2112, the gases entrain moisture when passing over or near water in the gas humidifier 2112. The water is heated by the heating element, which aids in the humidification and/or heating of the gases passing through the gas humidifier 2112. The gases leave the gas humidifier 2112 through the humidifier outlet 2118 and enter the second conduit 300. Prior to entering the second conduit 300, the gases receive one or more substances from the nebulizer 128. The gases are passed from the second conduit 300 to the nasal interface 100, where the gases are taken into the patient's airways to aid in the treatment of respiratory disorders.

[00620] Figure 27 shows an exemplary type of tubing or conduit 300 that can be used to deliver the gases to the nasal interface 100. The tubing or conduit 300 is illustrated featuring a smooth bore 3021 or a non-corrugated bore. This type of tubing is best described and illustrated in in US patent application publication no. 2014/0202462 (also published as PCT publication no. WO2012/164407A1) and PCT publication no. W02014/088430, for example. The contents of those specifications are incorporated herein in their entireties by way of reference. As described therein, the tubing is formed of a bead 3041 and a small tube or bubble 3061. In general, the peak to valley surface roughness of such tubing is on the order of 0.15-0.25 mm. In one configuration, the conduit or tubing has an internal bore diameter of 13-14 mm. The two components 3041, 3061 combine to define a conduit or tube with a lumen that has minimal surface deviations. In some configurations, the bead 304 contains wires 3081. One or more of the wires can be used for heating the wall of the conduit without being positioned within the flow being conveyed by the conduit or tubing 300. In the illustrated configuration, the bead 3041 contains four wires 3081. In some configurations, the bead 304 may contain two wires 3081. Other number of wires also can be used.

[00621] Figure 28 shows an alternative exemplary type of tubing or conduit 320 that can be used to deliver the gases to the nasal interface 100. With reference to Figure 28, the illustrated conduit or tubing 320 is corrugated tubing. In one configuration, the conduit or tubing 320 has an internal bore diameter of 20-21 mm. The corrugated tubing 320 includes deep furrows 322 along a wall 324 of the tubing 320. In many cases, the furrows 322 result in one or more helical interruption that extends along a length of the lumen defined by the wall 324. As such, the inner surface of the conduit or tubing is significantly rougher than the smooth bore tubing 300 illustrated in Figure 26. In general, the corrugated conduit or tubing has peak to valley surface roughness on the order of 1.5-2.5 mm. In the illustrated configuration of Figure 28, one or more heating wires 326 also can be coiled and positioned in direct contact with the gas flow through the lumen. When the wires are positioned within the gas flow path, the heater wire adds 2-3 mm of added "surface roughness" although this is merely an estimate of the effect of the heater wire being positioned within the gas flow path.

[00622] Use of the smooth bore heating tube 300, such as that illustrated in Figure 27, for use in drug transportation from the nebulizer 2128 described above, has resulted in significant increases in drug transportation efficiency compared to use of a more conventional heated breathing tube 320, such as that illustrated in Figure 28. The efficiency improvement is believed to be due to a large reduction of the amount of nebulised drug being caught within the furrows 322 and the exposed heating wires 326 of the more conventional heated breathing tube 320. For example, it has been estimated that 300% more of the nebulised drug is captured by the surfaces than that which is retained within the smooth bore heated breathing tube 300, such as that shown in Figure 27, for example but without limitation. It is believed there is a reduction in the deposition processes, such as impaction, due to less vorticity in the flow and less obstacles that present an effective roughness.

[00623] In some configurations, when the flow rate exceeds an optimal flow rate, the transportation efficiency has been found to decrease. In other words, at some high flow rates above 30 Ipm, the flow rate is somewhat inversely proportional to nebulization efficiency (i.e., high flow rates result in more medication become trapped within the circuit instead of being delivered to the patient).

[00624] With the nasal cannula 100 with nasal prongs 111, 112, a reduction in flow rate for an equivalent dead space clearance may be possible which may improve the provision of respiratory therapy with nebulized medicament. The nebulized medicament may be less likely to 'crash out' in which a portion of the medicament is deposited on the internal surface of the flow path instead of being delivered to the patient, or suffer from other losses owing to impacting on surfaces due to smoother flow transitions. With the partial unidirectional flow provided by the nasal interface 100, when a patient is breathing out against the flow, less medicament is wasted than may otherwise be the case. Other aspects of the nasal cannula 100 with nasal prongs 111, 112, including the cross-sectional areas of the prongs and the relationships of those cross-sectional areas, may improve the provision of respiratory therapy with nebulized medicament.

[00625] The patient interface 10 and nasal interface 100 used in the respiratory therapy system 2000 may have any one or more of the features and/or functionality described herein for nasal interfaces 100.

[00626] The respiratory therapy system 2000 may have any one or more of the features and/or functionality of the system described in PCT publication no. WO 2016/085354 or US patent application publication no. 2017/0312472. The contents of those specifications are incorporated herein in their entireties by way of reference.

[00627] Although the present disclosure has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art also are within the scope of this disclosure. Thus, various changes and modifications may be made without departing from the spirit and scope of the disclosure. For instance, various components may be repositioned as desired. Features from any of the described embodiments may be combined with each other and/or an apparatus may comprise one, more, or all of the features of the above described embodiments. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by the claims that follow.

[00628] For purposes of clarity, in the present disclosure the same reference numbers are used in the drawings to identify similar elements. However, for the sake of convenience, certain features present or annotated with reference numerals in some figures of the present disclosure are not shown or annotated with reference numerals in other figures of the present disclosure. Unless the context clearly requires otherwise, these omissions should not be interpreted to mean that features omitted from the drawings of one figure could not be equally incorporated or implemented in the configurations of the disclosed methods, apparatus and systems related to or embodied in other figures. Conversely, unless the context clearly requires otherwise, it should not be assumed that the presence of certain features in some figures of the present disclosure means that the disclosed methods, apparatus and systems related to or embodied in such figures must necessarily include these features.

CLAUSES

[00629] Additional embodiments are included in the flowing clauses or numbered statements. Clause 1. A nasal interface comprising: i. a first prong having a first base and a first terminal end; ii. a second prong having a second base and a second terminal end; iii. a gases manifold comprising a manifold chamber and a gases inlet; and iv. at least one element positioned within the first prong, second prong or manifold chamber, b. wherein the at least one element is configured to increase a resistance to a flow of gases travelling through at least one of the first prong, second prong, or manifold chamber and c. wherein the gases inlet is, or is configured to be, in fluid communication with a gases-conveying conduit.

Clause 2. The nasal interface of clause 1, wherein the increase in resistance to the flow of gases is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

Clause 3. The nasal interface of clause 1 or clause 2, wherein the at least one element is a second prong element positioned within the second prong.

Clause 4. The nasal interface of clause 3, wherein the second prong element is configured to increase a resistance to the flow of gases travelling through the second prong.

Clause 5. The nasal interface of clause 3 or clause 4, wherein the second prong element is positioned at the second base.

Clause 6. The nasal interface of any one of clauses 1 to 5, wherein the base of the second prong comprises an entrance to a flow passage formed by a wall of the second prong.

Clause 7. The nasal interface of any one of clauses 1 to 6, wherein the at least one element is a manifold element, wherein the manifold element is positioned within the manifold chamber of the gases manifold.

Clause 8. The nasal interface of clause 7, wherein the manifold element is configured to increase a resistance to a flow of gases travelling through the manifold chamber.

Clause 9. The nasal interface of any one of clauses 1 to 8, wherein the flow of gases is substantially in a direction from the gases manifold inlet, through the gases manifold chamber, and into a flow passage of the first prong and/or the second prong.

Clause 10. The nasal interface of clause 7 or clause 8, wherein the manifold element is positioned substantially in the centre of the manifold chamber.

Clause 11. The nasal interface of any one of clauses 3 to 5, wherein the nasal interface comprises a first prong element, wherein the first prong element is positioned within the first prong.

Clause 12. The nasal interface of clause 11, wherein the first prong element is configured to increase the resistance to a flow of gases travelling through the first prong. Clause 13. The nasal interface of clause 11 or clause 12, wherein the first prong element is positioned at the base of the first prong.

Clause 14. The nasal interface of clause 12, wherein the first prong element provides a different resistance to a flow of gases than the second prong element.

Clause 15. The nasal interface according to any one of clauses 1 to 14, wherein the gases conveying conduit is between a patient conduit and the gases inlet.

Clause 16. The nasal interface according to any one of clauses 1 to 15, wherein the gases manifold is integrally formed with the gases conveying conduit or is coupled to the gases conveying conduit.

Clause 17. The nasal interface according to any one of clauses 1 to 16, wherein the gases manifold comprises a manifold width, and wherein the manifold width is as large as or larger than an inner diameter of at least one of the first prong or second prong.

Clause 18. The nasal interface according to any one of clauses 1 to 17, wherein the nasal interface comprises a cannula body comprising the first prong and the second prong, and wherein an external surface of the cannula body between the first prong and the second prong comprises a dip to accommodate a portion of a patient's nose and reduce pressure on an underside of the accommodated portion.

Clause 19. The nasal interface according to any one of clauses 1 to 18, wherein at least one of the first prong or second prong is sized to maintain a sufficient gap between the outer surface of the at least one prong and a patient's skin to avoid sealing a gas path between the nasal interface and the patient.

Clause 20. The nasal interface according to any one of clauses 1 to 19, wherein at least the first prong or second prong is made of an elastomeric material that enables the first prong to deform and set its shape in use in response to temperature and contact with the patient's naris.

Clause 21. The nasal interface according to any one of clauses 1 to 20, wherein at least one of the first prong or second prong is not made of silicone.

Clause 22. The nasal interface according to any one of clauses 1 to 21, wherein at least one of the first prong or second prong is made of a thermoplastic elastomer.

Clause 23. The nasal interface according to any one of clauses 1 to 22, wherein the gases manifold comprises a flow channel that has a gases flow direction that is substantially perpendicular to gases flow paths through the first prong and the second prong.

Clause 24. The nasal interface of clause 7 or 8, wherein the manifold element comprises a manifold aperture for the passage of a gases flow, wherein said manifold aperture has a smaller cross-sectional opening than the manifold chamber for the gases flow.

Clause 25. The nasal interface of any one of clauses 3 to 5, wherein the second prong element comprises a second aperture for the passage of a gases flow, wherein said second aperture has a smaller cross-sectional opening than the second prong for the gases flow. Clause 26. The nasal interface of clause 24 or clause 25, wherein the manifold aperture and/or second aperture is formed in a plate or a wall.

Clause 27. The nasal interface of clause 26, wherein the plate or wall has an inlet surface and an outlet surface with the manifold aperture and/or second manifold formed therebetween.

Clause 28. The nasal interface of clause 27, wherein a gases flow is in the direction from the inlet surface to the outlet surface through the manifold aperture and/or second aperture.

Clause 29. The nasal interface of clause 27 or clause 28, wherein the transition between the outlet surface and the manifold aperture and/or second aperture is tapered.

Clause 30. The nasal interface of any one of clauses 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is substantially right angled.

Clause 31. The nasal interface of any one of clauses 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

Clause 32. The nasal interface of any one of clauses 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is substantially a sharp corner.

Clause 33. The nasal interface of any one of clauses 26 to 32, wherein the at least one manifold aperture and/or second aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

Clause 34. The nasal interface of any one of clauses 26 to 32, wherein the at least one manifold aperture and/or second aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall.

Clause 35. The nasal interface of any one of clauses 24 to 34, wherein the at least one manifold aperture and/or second aperture is a substantially circular perforation.

Clause 36. The nasal interface of any one of clauses 24 to 35, wherein the at least one manifold aperture and/or second aperture comprises a pattern of perforations.

Clause 37. The nasal interface of any one of clauses 26 to 34, wherein the plate or wall of the at least one manifold aperture and/or second aperture comprises a porous medium.

Clause 38. The nasal interface of any one of clauses 1 to 37, wherein the at least one element comprises a valve.

Clause 39. The nasal interface of clause 38, wherein the valve is configured to open only at a threshold pressure or flow rate.

Clause 40. The nasal interface of clause 38 or clause 39, wherein the valve is configured to provide a defined pressure drop in the flow path. Clause 41. The nasal interface of any one of clauses 38 to 40, wherein the valve is a duckbill valve.

Clause 42. The nasal interface of any one of clauses 1 to 41, wherein the at least one element comprises a nozzle.

Clause 43. The nasal interface of clause 42, wherein the nozzle is configured to provide a defined pressure drop in the flow path.

Clause 44. The nasal interface of clause 7 or clause 8, wherein the manifold element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

Clause 45. The nasal interface of clause 44, wherein the manifold element is configured to be slidably movable in an upstream-downstream direction.

Clause 46. The nasal interface of clause 44, wherein the manifold element comprises a rotatable piece with a helical thread.

Clause 47. The nasal interface of clause 45 or clause 46, wherein the manifold element further comprises a portion external to the gases manifold of the nasal interface.

Clause 48. The nasal interface of clause 47, wherein the manifold element is configured to be rotatably movable, such that when the external portion is rotated, the manifold element translates vertically into or out the manifold chamber flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

Clause 49. The nasal interface of any one of clauses 1 to 48, wherein the gases manifold comprises an opening at a wall approximately opposite the gases inlet of the manifold and/or approximately opposite the second base of the second prong.

Clause 50. The nasal interface of clause 49, wherein the opening comprises one or a plurality of apertures.

Clause 51. The nasal interface of clause 50, wherein the number and diameter of said apertures are configured to provide a defined pressure drop.

Clause 52. The nasal interface of any one of clauses 49 to 51, wherein the opening in the wall of the manifold is pneumatically connected to a component configured to provide a defined pressure drop.

Clause 53. The nasal interface of clause 52, wherein the component is at least one of a porous medium, a nozzle, a pressure- re lief valve, an auxiliary tube, or a bubble CPAP bubbling chamber.

Clause 54. The nasal interface of any one of clauses 1 to 53, wherein an axis of the gases inlet is co-axial relative to an axis of at least one of the first prong or second prong. Clause 55. The nasal interface of any one of clauses 1 to 53, wherein the angle of the axis of the gases inlet is perpendicular relative to an axis of at least the first prong or second prong.

Clause 56. The nasal interface of any one of clauses 1 to 55, wherein the gases manifold comprises a second gases inlet.

Clause 57. The nasal interface of any one of clauses 1 to 56, wherein the nasal interface comprises an auxiliary gases inlet to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 58. The nasal interface of clause 57, wherein the auxiliary gases inlet terminates in the first prong or the second prong.

Clause 59. The nasal interface of clause 57 or 58, wherein the auxiliary gases inlet is in fluid communication with an auxiliary gases conveying conduit.

Clause 60. The nasal interface of any one of clauses 57 to 59, wherein at least one of the gases inlet or gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the auxiliary gases inlet or auxiliary gases conveying conduit comprises a lumen with a second internal cross-sectional area.

Clause 61. The nasal interface of clause 60, wherein the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

Clause 62. The nasal interface of clause 61 or clause 62, wherein the first internal cross-sectional area and the second internal cross-sectional area are different.

Clause 63. The nasal interface of clause 63, wherein second internal cross-sectional area is smaller than an internal cross-sectional area of the first prong or second prong.

Clause 64. The nasal interface of clause 59, wherein the gases conveying conduit and the auxiliary gases conveying conduit are disposed on the same side of the manifold chamber.

Clause 65. The nasal interface of any one of clause 59, wherein the auxiliary gases conveying conduit is positioned in the gases conveying conduit.

Clause 66. The nasal interface of clause 59, wherein at least one of the gases inlet or the gases conveying conduit comprises a first length and at least one of the auxiliary gases inlet or the auxiliary gases conveying conduit comprises a second length.

Clause 67. The nasal interface of clause 66, wherein the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 68. The nasal interface of clause 66 or clause 67, wherein the first length is longer than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong. Clause 69. The nasal interface of clause 66 or clause 67, wherein the first length is shorter than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 70. The nasal interface of clause 59, wherein the gases conveying conduit is in communication with a first gases flow and the auxiliary gases conveying conduit is in communication with a second gases flow.

Clause 71. The nasal interface of clause 70, wherein the first gases flow has a different flow rate to the second gases flow.

Clause 72. The nasal interface of clause 70 or clause 71, wherein a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

Clause 73. The nasal interface of any one of clauses 70 to 72, wherein one of the first or second gases flow is a suction flow.

Clause 74. The nasal interface of any one of clauses 70 to 73, wherein a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

Clause 75. The nasal interface of clause 74, wherein a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

Clause 76. A nasal interface comprising: i. a first prong having a first base and a first terminal end; ii. a second prong having a second base and a second terminal end; and iii. a gases manifold comprising:

1. a manifold chamber;

2. a first gases inlet; and

3. a second gases inlet, b. wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, i. wherein the nasal interface is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

Clause 77. The nasal interface of clause 76, wherein the first gases inlet and the second gases inlet are disposed on opposite sides of the manifold chamber.

Clause 78. The nasal interface of clause 76 or clause 77, wherein the first gases inlet is more proximal to the first prong than the second inlet and wherein the second inlet is more proximal to the second prong than the first inlet.

Clause 79. The nasal interface of any one of clauses 76 to 78, wherein at least one of the first gases inlet and first gases conveying conduit is formed as a unitary structure or the second gases inlet and second gases conveying conduit is formed as a unitary structure.

Clause 80. The nasal interface of any one of clauses 76 to 79, wherein the first gases conveying conduit is in communication with a first gases flow and the second gases conveying conduit is in communication with a second gases flow. Clause 81. The nasal interface of clause 80, wherein the first gases flow has a different flow rate to the second gases flow.

Clause 82. The nasal interface of clause 80 or clause 81, wherein a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

Clause 83. The nasal interface of any one of clauses 80 to 82 wherein one of the first or second gases flow is a suction flow.

Clause 84. The nasal interface of any one of clauses 80 to 83, wherein a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

Clause 85. The nasal interface of clause 84, wherein a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

Clause 86. The nasal interface of any one of clauses 76 to 85, wherein the at least one of first inlet or first gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the second inlet or second gases conveying conduit comprises a lumen with a second internal cross-sectional area.

Clause 87. The nasal interface of clause 86, wherein the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

Clause 88. The nasal interface of clause 86, wherein the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially non-circular.

Clause 89. The nasal interface of any one of clauses 86 to 88, wherein the first internal cross-sectional area and the second internal cross-sectional area are unequal to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 90. The nasal interface of any one of clauses 86 to 89, wherein the first internal cross-sectional area is larger than the second internal cross-sectional area to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 91. The nasal interface of any one of clauses 86 to 89, wherein the first internal cross-sectional area is smaller than the second internal cross-sectional area to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 92. The nasal interface of any one of clauses 76 to 91, wherein at least one of the first inlet or the first gases conveying conduit comprises a first length and at least one of the second inlet or the second gases conveying conduit comprises a second length.

Clause 93. The nasal interface of clause 92, wherein the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong. Clause 94. The nasal interface of clause 92 or clause 93, wherein the first length is longer than the second length to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 95. The nasal interface of clause 92 or clause 93, wherein the first length is shorter than the second length to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 96. The nasal interface of any one of clauses 76 to 95, wherein the internal surface of at least one of the first inlet or first gases conveying conduit comprises a first pattern of relief features.

Clause 97. The nasal interface of any one of clauses 76 to 96, wherein the internal surface of at least one of the second inlet or second gases conveying conduit comprises a second pattern of relief features.

Clause 98. The nasal interface of clause 97 when dependent on clause 96, wherein the first pattern of relief features is substantially rougher than the second pattern of relief features to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 99. The nasal interface of clause 97 when dependent on clause 96, wherein the first pattern of relief features is substantially smoother than the second pattern of relief features to cause the asymmetrical flow of gases at the first prong and the second prong.

Clause 100. The nasal interface of any one of clauses 96 to 99, wherein the pattern of relief features comprises one or more of: dimples, protrusions, ribs, and/or fins.

Clause 101. The nasal interface of any one of clauses 76 to 100, wherein an axis of at least one of the first gases inlet or second gases inlet is co-axial relative to an axis of at least one of the first prong or second prong.

Clause 102. The nasal interface of any one of clauses 76 to 100, wherein the angle of the axis of the first gases inlet and/or second gases inlet is perpendicular relative to the axis of at least one of the first prong or second prong .

Clause 103. The nasal interface of any one of clauses 76 to 102, comprising at least one of:

(i) a first prong element positioned within the first prong;

(ii) a second prong element positioned within the second prong;

(iii) a manifold element positioned in the manifold chamber and between the first base of the first prong and the second base of the second prong;

(iv) a first gases inlet element positioned at the first gases inlet to the gases manifold; or

(v) a second gases inlet element positioned at the second gases inlet to the gases manifold, a. wherein the first prong element, second prong element, manifold element, first gases inlet element and/or second gases inlet element are each configured to increase the resistance to a flow of gases entering said respective element to cause the asymmetrical flow of gases at the first prong and the second prong. Clause 104. The nasal interface of clause 103, comprising the first gases inlet element and the second gases inlet element each configured to increase the resistance to flow of a flow of gases entering the manifold through the first gases inlet and second gases inlet respectively.

Clause 105. The nasal interface of clause 103, comprising the first prong element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the first prong and second prong respectively.

Clause 106. The nasal interface of clause 103, comprising the manifold element and the first gases inlet element each configured to increase the resistance to flow to a flow of gases within the manifold chamber and entering the manifold through the manifold element and first gases inlet element respectively.

Clause 107. The nasal interface of clause 103, comprising the manifold element and the second gases inlet element each configured to increase the resistance to flow to a flow of gases within the manifold chamber and entering the manifold through manifold element and the second gases inlet element respectively.

Clause 108. The nasal interface of any one of clauses 103 to 107, wherein, when present, at least one of the first prong element, the second prong element, the manifold element, the first gases inlet element or the second gases inlet element comprises an aperture for a reduced passage of a gases flow.

Clause 109. The nasal interface of clause 108, wherein the aperture is formed in a plate or a wall.

Clause 110. The nasal interface of clause 109, wherein the plate or wall has an inlet surface and an outlet surface with the aperture formed therebetween.

Clause 111. The nasal interface of clause 110, wherein a gases flow is in the direction from the inlet surface to the outlet surface through the aperture.

Clause 112. The nasal interface of clause 109 or clause 110, wherein the transition between the outlet surface and the aperture is tapered.

Clause 113. The nasal interface of any one of clauses 109 to 112, wherein the transition between the inlet surface and the aperture is substantially right angled.

Clause 114. The nasal interface of any one of clauses 109 to 112, wherein the transition between the inlet surface and the aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

Clause 115. The nasal interface of any one of clauses 109 to 112, wherein the transition between the inlet surface and the aperture is substantially a sharp corner.

Clause 116. The nasal interface of any one of clauses 109 to 115, wherein the at least one aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

Clause 117. The nasal interface of any one of clauses 109 to 115, wherein the at least one aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall. Clause 118. The nasal interface of any one of clauses 108 to 115, wherein the at least one aperture is a substantially circular perforation.

Clause 119. The nasal interface of any one of clauses 108 to 115, wherein the at least one aperture comprises a pattern of perforations.

Clause 120. The nasal interface of any one of clauses 109 to 115, wherein the plate or wall of the at least one aperture comprises a porous medium.

Clause 121. The nasal interface of any one of clauses 103 to 108, wherein, when present, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element comprises a valve.

Clause 122. The nasal interface of clause 121, wherein the valve is configured to open only at a threshold pressure or flow rate.

Clause 123. The nasal interface of clause 121 or clause 122, wherein the valve is configured to provide a defined pressure drop in the flow path.

Clause 124. The nasal interface of any one of clauses 121 to 123, wherein the valve is a duckbill valve.

Clause 125. The nasal interface of any one of clauses 103 to 124, wherein, when present, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element comprises a nozzle.

Clause 126. The nasal interface of clause 125, wherein the nozzle is configured to provide a defined pressure drop in the flow path.

Clause 127. The nasal interface of any one of clauses 103 to 126, wherein, when present, at least one of the first prong element, the second prong element, the manifold element, the first gases element or the second gases element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

Clause 128. The nasal interface of clause 127, wherein the element is configured to be slidably movable in an upstream-downstream direction.

Clause 129. The nasal interface of clause 128, wherein the element comprises a rotatable piece with a helical thread.

Clause 130. The nasal interface of clause 129, wherein the element further comprises a portion external to the nasal interface.

Clause 131. The nasal interface of clause 130, wherein the element is configured to be rotatably movable, such that when the external portion is rotated, the element translates vertically into or out the flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

Clause 132. A nasal interface comprising: i. a first prong and a second prong; ii. a gases manifold comprising a manifold chamber and a gases inlet, the gases inlet is, or is configured to be, in fluid communication with a gases-conveying conduit; and

Hi. at least one flow-directing element formed as part of at least one of the manifold chamber, gases inlet or gases-conveying conduit, b. wherein the at least one flow-directing element is configured to direct a flow of gases to one of the first prong or second prong to create an asymmetric flow of gases.

Clause 133. The nasal interface according to clause 132, wherein the flow directing element is configured to provide a larger dynamic pressure at the first prong in use and to provide a smaller dynamic pressure at the second prong in use, to create the asymmetric flow of gases.

Clause 134. The nasal interface according to clauses 132 or clause 133, wherein at least one of the first prong or second prong is sized to maintain a sufficient gap between the outer surface of the at least one prong and a patient's skin to avoid sealing a gas path between the nasal interface and the patient.

Clause 135. The nasal interface of any one of clauses 132 to 134, wherein the first prong and second prong are in fluid communication with the manifold chamber.

Clause 136. The nasal interface of any one of clauses 132 to 135, wherein the gases inlet is positioned in the manifold chamber opposite at least one of the first prong or second prong.

Clause 137. The nasal interface of any one of clauses 132 to 137, wherein an axis of the gases inlet is co-axial relative to an axis of at least one of the first prong or second prong.

Clause 138. The nasal interface of clause 132 to 136, wherein the angle of the axis of the gases inlet is perpendicular relative to the axis of at least one of the first prong or second prong.

Clause 139. The nasal interface of any one of clauses 134 to 138, wherein the at least one flow-directing element is positioned within the gases manifold chamber.

Clause 140. The nasal interface of any one of clauses 134 to 138, wherein the at least one flow-directing element is positioned within the gases-conveying conduit.

Clause 141. The nasal interface of clause 140, wherein the at least one flowdirecting element is positioned within the gases-conveying conduit, where the gases-conveying conduit meets the gases inlet.

Clause 142. The nasal interface of any one of clauses 134 to 141, wherein the at least one flow-directing element comprises at least one angled protrusion, wherein the protrusion is configured to direct a flow of gases towards one of the first prong or second prong from the gases inlet.

Clause 143. The nasal interface of clause 142, wherein the at least one flowdirecting element further comprises a second angled protrusion, positioned opposite the first protrusion in the flow path and configured likewise to direct a flow of gases towards one of the first prong or second prong from the gases inlet. Clause 144. The nasal interface of any one of clauses 134 to 143, comprising a second flow-directing element, positioned at the entrance to one of the first prong or second prong in the gases manifold.

Clause 145. The nasal interface of clause 144, wherein the second flow-directing element is configured to direct a flow of gases towards one of the first prong or second prong from the gases inlet.

Clause 146. The nasal interface of clause 144 or clause 145, wherein the second flow-directing element is configured to direct a flow of exhalation gases from the first prong or second prong to the opposing prong.

Clause 147. The nasal interface of clause 144 or clause 145, wherein the second flow-directing element comprises at least one angled protrusion, wherein the protrusion is configured to direct a flow of gases of gases towards one of the first prong or second prong from the gases inlet, and is configured to direct a flow of exhalation gases from the first prong or second prong to the opposing prong.

Clause 148. The nasal interface of any one of clauses 134 to 147, wherein the gases inlet is positioned in the manifold chamber at a position substantially centrally between the first prong and the second prong.

Clause 149. The nasal interface of any one of clauses 134 to 148, wherein the at least one flow-directing element is positioned within the gases manifold chamber and is proximal to the first prong.

Clause 150. The nasal interface of any one of clauses 134 to 149, wherein the at least one flow-directing element is configured to direct the gases flow from the gases-conveying conduit towards the entrance of the first prong.

Clause 151. The nasal interface of any one of clauses 144 to 147, wherein the second flow-directing element is configured to direct the gases flow from the entrance of the first prong into a first prong flow passage.

Clause 152. The nasal interface of any one of clauses 134 to 151, wherein the at least one flow-directing element is positioned within the gases manifold chamber and is proximal to the second prong.

Clause 153. The nasal interface of any one of clauses 134 to 148, wherein the at least one flow-directing element is configured to direct the gases flow from the gases-conveying conduit towards the entrance of the second prong.

Clause 154. The nasal interface of any one of clauses 144 to 147, wherein the second flow-directing element is configured to direct the gases flow from the entrance of the second prong into a second prong flow passage.

Clause 155. The nasal interface of any one of clauses 134 to 154, comprising at least one of:

(i) a first prong element positioned within the first prong;

(ii) a second prong element positioned within the second prong;

(iii) a manifold element positioned in the manifold chamber and between the first base of the first prong and the second base of the second prong; b. wherein the first prong element, second prong element and/or manifold element are each configured to increase the resistance to flow of a flow of gases entering said respective element.

Clause 156. The nasal interface of clause 155, comprising the first prong element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the first prong and second prong respectively.

Clause 157. The nasal interface of clause 155, comprising the manifold element and the second prong element each configured to increase the resistance to flow to a flow of gases entering the prong and within the manifold chamber through the second prong element and manifold element respectively.

Clause 158. The nasal interface of any one of clauses 155 to 157, wherein, when present, at least one of the first prong element, the second prong element and/or the manifold element comprises an aperture for a reduced passage of a gases flow.

Clause 159. The nasal interface of clause 158, wherein the aperture is formed in a plate or a wall.

Clause 160. The nasal interface of clause 159, wherein the plate or wall has an inlet surface and an outlet surface with the aperture formed therebetween.

Clause 161. The nasal interface of clause 160, wherein a gases flow is in the direction from the inlet surface to the outlet surface through the aperture.

Clause 162. The nasal interface of clause 160 or clause 161, wherein the transition between the outlet surface and the aperture is tapered.

Clause 163. The nasal interface of any one of clauses 160 to 162, wherein the transition between the inlet surface and the aperture is substantially right angled.

Clause 164. The nasal interface of any one of clauses 160 to 162, wherein the transition between the inlet surface and the aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

Clause 165. The nasal interface of any one of clauses 160 to 162, wherein the transition between the inlet surface and the aperture is substantially a sharp corner.

Clause 166. The nasal interface of any one of clauses 159 to 165, wherein the at least one aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

Clause 167. The nasal interface of any one of clauses 159 to 165, wherein the at least one aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall.

Clause 168. The nasal interface of any one of clauses 158 to 167, wherein the at least one aperture is a substantially circular perforation.

Clause 169. The nasal interface of any one of clauses 158 to 167, wherein the at least one aperture comprises a pattern of perforations. Clause 170. The nasal interface of any one of clauses 159 to 169, wherein the plate or wall of the at least one aperture comprises a porous medium.

Clause 171. The nasal interface of any one of clauses 155 to 170, wherein, when present, at least one of the first prong element, the second prong element and/or the manifold element comprises a valve.

Clause 172. The nasal interface of clause 171, wherein the valve is configured to open only at a threshold pressure or flow rate.

Clause 173. The nasal interface of clause 171 or clause 172, wherein the valve is configured to provide a defined pressure drop in the flow path.

Clause 174. The nasal interface of any one of clauses 171 to 173, wherein the valve is a duckbill valve.

Clause 175. The nasal interface of any one of clauses 155 to 174, wherein, when present, at least one of the first prong element, the second prong element and/or the manifold element comprises a nozzle.

Clause 176. The nasal interface of clause 175, wherein the nozzle is configured to provide a defined pressure drop in the flow path.

Clause 177. The nasal interface of any one of clauses 155 to 176, wherein, when present, at least one of the first prong element, the second prong element and/or the manifold element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

Clause 178. The nasal interface of clause 177, wherein the element is configured to be slidably movable in an upstream-downstream direction.

Clause 179. The nasal interface of clause 177, wherein the element comprises a rotatable piece with a helical thread.

Clause 180. The nasal interface of clause 179, wherein the element further comprises a portion external to the nasal interface.

Clause 181. The nasal interface of clause 180, wherein the element is configured to be rotatably movable, such that when the external portion is rotated, the element translates vertically into or out the flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

Clause 182. The nasal interface of any one of clauses 1 to 181, wherein the first prong has a first prong length and the second prong has a second prong length, and wherein the first prong length is different to the second prong length.

Clause 183. The nasal interface of clause 182, wherein the first prong length is longer than the second prong length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 184. The nasal interface of clause 182 or clause 183, wherein the first prong length is shorter than the second prong length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong. Clause 185. The nasal interface of any one of clauses 1 to 184, wherein the first prong has a first prong cross-sectional width and the second prong has a second prong cross-sectional width, and wherein the first prong cross-sectional width is different to the second prong cross-sectional width.

Clause 186. The nasal interface of clause 185, wherein the first prong cross- sectional width is larger than the second prong cross-sectional width to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 187. The nasal interface of clause 185, wherein the first prong cross- sectional width is smaller than the second prong cross-sectional width to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 188. The nasal interface of any one of clauses 1 to 187, wherein the first prong has a or the first terminal end and the second prong has a second terminal end, and wherein geometries of the first terminal end and second terminal end are different to cause or contribute to the asymmetrical flow of gases at the first prong and at the second prong.

Clause 189. The nasal interface of clause 188, wherein at least one of the first terminal end or the second terminal end is narrowed or tapered to form a nozzle shape.

Clause 190. The nasal interface of clause 188 or clause 189, wherein at least one of the first terminal end or the second terminal end is widened or tapered to form a diffuser shape.

Clause 191. The nasal interface of any one of clauses 1 to 190, wherein the first prong has a first internal surface and the second prong has a second internal surface, wherein at least one of the first internal surface or second internal surface has surface features configured to effect internal flow resistances of the at least one first prong or second prong.

Clause 192. The nasal interface of clause 191, wherein the surface features are ridges formed as rings, spirals or strips in a concentric pattern around the first or second internal surface.

Clause 193. The nasal interface of clause 190 or 191, wherein the surface features are fins formed as lines, strips or bars in a substantially axial directional pattern along the first or second surface.

Clause 194. The nasal interface of any one of clauses 191 to 193, wherein when the surface features are present on the first and second internal surface, the surface features are different to cause the asymmetrical flow of gases at the first prong and at the second prong.

Clause 195. The nasal interface of any one of clauses 1 to 194, wherein at least one of the first prong and second prong is a non-circular cross-sectional shape, the non-circular cross-sectional shape configured to effect internal flow resistances of the at least one first prong or second prong.

Clause 196. The nasal interface of clause 195, wherein the non-circular cross- sectional shape is reduced by the size of a circular cross-sectional shape removed therefrom. Clause 197. The nasal interface of clause 195, wherein the non-circular cross- sectional shape is substantially U-shaped.

Clause 198. The nasal interface of clause 195, wherein the non-circular cross- sectional shape is substantially polygonal.

Clause 199. The nasal interface of any one of clauses 195 to 198, wherein when the non-circular cross-sectional shape is present on each of the first and second prongs, the non-circular cross-sectional shapes are different to cause or contribute to the asymmetrical flow of gases at the first prong and at the second prong.

Clause 200. The nasal interface of any one of clauses 1 to 199, wherein at least one of the first prong and second prong comprises a base restriction at a base of the prong, the base restriction configured to effect internal flow resistances of the at least one first prong or second prong.

Clause 201. The nasal interface of clause 200, wherein the base restriction is a nozzle or a diffuser formed at the base of the prong.

Clause 202. The nasal interface of clause 200 or clause 201, wherein when the base restriction is present on the first and second prongs, the base restrictions are different to cause or contribute to the asymmetrical flow of gases at the first prong and at the second prong.

Clause 203. The nasal interface of any one of clauses 1 to 202, wherein at least one of the first prong and second prong comprises a prong valve within the prong, the prong valve configured to effect internal flow resistances of the at least one first prong or second prong.

Clause 204. The nasal interface of clause 203, wherein the prong valve is configured to restrict or prevent a gases flow therethrough until the gases flow exceeds a defined pressure.

Clause 205. The nasal interface of clause 203 or clause 204, wherein the prong valve is a duckbill valve.

Clause 206. The nasal interface of any one of clauses 203 to 205, wherein the prong valve is a one-way valve.

Clause 207. The nasal interface of any one of clauses 203 to 206, wherein when the prong valve is present in each of the first and second prongs, the prong valves have different characteristics to cause the asymmetrical flow of gases at the first prong and at the second prong.

Clause 208. The nasal interface of any one of clauses 1 to 207, further comprising a third prong, wherein the first, second and third prongs are spaced apart to be engageable into the nares of a patient as adjacent pairs, wherein at least one of the first, second or third prongs have different flow characteristics to the other prongs to cause or contribute to the asymmetrical flow of gases at the respective prongs.

Clause 209. The nasal interface of clause 208, further comprising a closure for releasably preventing a flow of gases through the first, second or third prong.

Clause 210. A nasal interface comprising: i. a first prong having a first base and a first terminal end; ii. a second prong having a second base and a second terminal end;

Hi. a gases manifold; iv. a first gases inlet; and v. an auxiliary gases inlet, vi. wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, vii. wherein the nasal interface is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

Clause 211. The nasal interface of clause 210, wherein the first gases inlet terminates in the gases manifold.

Clause 212. The nasal interface of clause 201 or clause 211, wherein the auxiliary gases inlet terminates in the first prong or the second prong.

Clause 213. The nasal interface of any one of clauses 210 to 212, wherein the auxiliary gases inlet is in fluid communication with an auxiliary gases conveying conduit.

Clause 214. The nasal interface of any one of clauses 210 to 213, wherein at least one of the gases inlet or gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the auxiliary gases inlet or auxiliary gases conveying conduit comprises a lumen with a second internal cross- sectional area.

Clause 215. The nasal interface of clause 214, wherein the one or both of the first internal cross-sectional area and the second internal cross-sectional area are substantially circular.

Clause 216. The nasal interface of clause 214 or clause 215, wherein the first internal cross-sectional area and the second internal cross-sectional area are different.

Clause 217. The nasal interface of clause 216, wherein the second internal cross-sectional area is smaller than an internal cross-sectional area of the first prong or second prong.

Clause 218. The nasal interface of clause 213, wherein the gases conveying conduit and the auxiliary gases conveying conduit are disposed on the same side of the gases manifold.

Clause 219. The nasal interface of any one of clause 213, wherein the auxiliary gases conveying conduit is positioned in the gases conveying conduit.

Clause 220. The nasal interface of clause 213, wherein at least one of the gases inlet or the gases conveying conduit comprises a first length and at least one of the auxiliary gases inlet or the auxiliary gases conveying conduit comprises a second length.

Clause 221. The nasal interface of clause 220, wherein the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong. Clause 222. The nasal interface of clause 220 or clause 221, wherein the first length is longer than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 223. The nasal interface of clause 220 or clause 221, wherein the first length is shorter than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

Clause 224. The nasal interface of clause 214, wherein the gases conveying conduit is in communication with a first gases flow and the auxiliary gases conveying conduit is in communication with a second gases flow.

Clause 225. The nasal interface of clause 224, wherein the first gases flow has a different flow rate to the second gases flow.

Clause 226. The nasal interface of clause 224 or clause 225, wherein a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

Clause 227. The nasal interface of any one of clauses 224 to 226, wherein one of the first or second gases flow is a suction flow.

Clause 228. The nasal interface of any one of clauses 224 to 227, wherein a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

Clause 229. The nasal interface of clause 228, wherein a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

Clause 230. A patient interface comprising the nasal interface according to any one of clauses 1 to 229.

Clause 231. The patient interface according to clause 230, further comprising a headgear to retain the nasal interface against a patient's face.

Clause 232. The patient interface according to clause 230 or 231, further comprising the gases-conveying conduit that is in fluid communication with the gases inlet.

Clause 233. The patient interface according to clause 232, wherein the gases- conveying conduit is a breathable tube.

Clause 234. The patent interface according to clause 233, wherein the gases manifold is integrally formed with the gases-conveying conduit or is coupled to the gases-conveying conduit.

Clause 235. The patient interface according to any one of clauses 232 to 234, wherein the gases-conveying conduit couples the gases inlet to a patient conduit that provides gases from a flow generator.

Clause 236. The patient interface according to any one of clauses 232 to 235 further comprising a gases-conveying conduit retention clip. Clause 237. A respiratory therapy system comprising: i. a respiratory therapy apparatus comprising: ii. a controller; iii. a blood oxygen saturation sensor; iv. an ambient air inlet; v. an oxygen inlet; vi. a valve in fluid communication with the oxygen inlet to control a flow of oxygen through the oxygen inlet; and vii. a gases outlet; b. wherein the controller is configured to control the valve based on at least one measurement of oxygen saturation from the blood oxygen saturation sensor; and i. a patient interface according to any one of clauses 230 to 236.

Claims

CLAIMS:

1. A nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold comprising a manifold chamber and a gases inlet; and at least one element positioned within the first prong, second prong or manifold chamber, wherein the at least one element is configured to increase a resistance to a flow of gases travelling through at least one of the first prong, second prong, or manifold chamber and wherein the gases inlet is, or is configured to be, in fluid communication with a gases-conveying conduit.

2. The nasal interface of claim 1, wherein the increase in resistance to the flow of gases is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

3. The nasal interface of claim 1 or claim 2, wherein the at least one element is a second prong element positioned within the second prong.

4. The nasal interface of claim 3, wherein the second prong element is configured to increase a resistance to the flow of gases travelling through the second prong.

5. The nasal interface of claim 3 or claim 4, wherein the second prong element is positioned at the second base.

6. The nasal interface of any one of claims 1 to 5, wherein the base of the second prong comprises an entrance to a flow passage formed by a wall of the second prong.

7. The nasal interface of any one of claims 1 to 6, wherein the at least one element is a manifold element, wherein the manifold element is positioned within the manifold chamber of the gases manifold.

8. The nasal interface of claim 7, wherein the manifold element is configured to increase a resistance to a flow of gases travelling through the manifold chamber.

9. The nasal interface of any one of claims 1 to 8, wherein the flow of gases is substantially in a direction from the gases manifold inlet, through the gases manifold chamber, and into a flow passage of the first prong and/or the second prong.

10. The nasal interface of claim 7 or claim 8, wherein the manifold element is positioned substantially in the centre of the manifold chamber.

11. The nasal interface of any one of claims 3 to 5, wherein the nasal interface comprises a first prong element, wherein the first prong element is positioned within the first prong.

12. The nasal interface of claim 11, wherein the first prong element is configured to increase the resistance to a flow of gases travelling through the first prong.

13. The nasal interface of claim 11 or claim 12, wherein the first prong element is positioned at the base of the first prong.

14. The nasal interface of claim 12, wherein the first prong element provides a different resistance to a flow of gases than the second prong element.

15. The nasal interface according to any one of claims 1 to 14, wherein the gases conveying conduit is between a patient conduit and the gases inlet.

16. The nasal interface according to any one of claims 1 to 15, wherein the gases manifold is integrally formed with the gases conveying conduit or is coupled to the gases conveying conduit.

17. The nasal interface according to any one of claims 1 to 16, wherein the gases manifold comprises a manifold width, and wherein the manifold width is as large as or larger than an inner diameter of at least one of the first prong or second prong.

18. The nasal interface according to any one of claims 1 to 17, wherein the nasal interface comprises a cannula body comprising the first prong and the second prong, and wherein an external surface of the cannula body between the first prong and the second prong comprises a dip to accommodate a portion of a patient's nose and reduce pressure on an underside of the accommodated portion.

19. The nasal interface according to any one of claims 1 to 18, wherein at least one of the first prong or second prong is sized to maintain a sufficient gap between the outer surface of the at least one prong and a patient's skin to avoid sealing a gas path between the nasal interface and the patient.

20. The nasal interface according to any one of claims 1 to 19, wherein at least the first prong or second prong is made of an elastomeric material that enables the first prong to deform and set its shape in use in response to temperature and contact with the patient's naris.

21. The nasal interface according to any one of claims 1 to 20, wherein at least one of the first prong or second prong is not made of silicone.

22. The nasal interface according to any one of claims 1 to 21, wherein at least one of the first prong or second prong is made of a thermoplastic elastomer.

23. The nasal interface according to any one of claims 1 to 22, wherein the gases manifold comprises a flow channel that has a gases flow direction that is substantially perpendicular to gases flow paths through the first prong and the second prong.

24. The nasal interface of claim 7 or 8, wherein the manifold element comprises a manifold aperture for the passage of a gases flow, wherein said manifold aperture has a smaller cross-sectional opening than the manifold chamber for the gases flow.

25. The nasal interface of any one of claims 3 to 5, wherein the second prong element comprises a second aperture for the passage of a gases flow, wherein said second aperture has a smaller cross-sectional opening than the second prong for the gases flow.

26. The nasal interface of claim 24 or claim 25, wherein the manifold aperture and/or second aperture is formed in a plate or a wall.

27. The nasal interface of claim 26, wherein the plate or wall has an inlet surface and an outlet surface with the manifold aperture and/or second manifold formed therebetween.

28. The nasal interface of claim 27 , wherein a gases flow is in the direction from the inlet surface to the outlet surface through the manifold aperture and/or second aperture.

29. The nasal interface of claim 27 or claim 28, wherein the transition between the outlet surface and the manifold aperture and/or second aperture is tapered.

30. The nasal interface of any one of claims 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is substantially right angled.

31. The nasal interface of any one of claims 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is tapered, wherein the taper angle of the outlet surface is greater than that of the inlet surface.

32. The nasal interface of any one of claims 27 to 29, wherein the transition between the inlet surface and the manifold aperture and/or second aperture is substantially a sharp corner.

33. The nasal interface of any one of claims 26 to 32, wherein the at least one manifold aperture and/or second aperture is a gap, cut or slit extending vertically lengthwise through the plate or wall.

34. The nasal interface of any one of claims 26 to 32, wherein the at least one manifold aperture and/or second aperture is a gap, cut or slit extending horizontally lengthwise through the plate or wall.

35. The nasal interface of any one of claims 24 to 34, wherein the at least one manifold aperture and/or second aperture is a substantially circular perforation.

36. The nasal interface of any one of claims 24 to 35, wherein the at least one manifold aperture and/or second aperture comprises a pattern of perforations.

37. The nasal interface of any one of claims 26 to 34, wherein the plate or wall of the at least one manifold aperture and/or second aperture comprises a porous medium.

38. The nasal interface of any one of claims 1 to 37, wherein the at least one element comprises a valve.

39. The nasal interface of claim 38, wherein the valve is configured to open only at a threshold pressure or flow rate.

40. The nasal interface of claim 38 or claim 39, wherein the valve is configured to provide a defined pressure drop in the flow path.

41. The nasal interface of any one of claims 38 to 40, wherein the valve is a duckbill valve.

42. The nasal interface of any one of claims 1 to 41, wherein the at least one element comprises a nozzle.

43. The nasal interface of claim 42, wherein the nozzle is configured to provide a defined pressure drop in the flow path.

44. The nasal interface of claim 7 or claim 8, wherein the manifold element is configured to be adjusted via manual actuation, to increase or decrease a degree of restriction by the element.

45. The nasal interface of claim 44, wherein the manifold element is configured to be slidably movable in an upstream-downstream direction.

46. The nasal interface of claim 44, wherein the manifold element comprises a rotatable piece with a helical thread.

47. The nasal interface of claim 45 or claim 46, wherein the manifold element further comprises a portion external to the gases manifold of the nasal interface.

48. The nasal interface of claim 47, wherein the manifold element is configured to be rotatably movable, such that when the external portion is rotated, the manifold element translates vertically into or out the manifold chamber flow path, thereby increasing or decreasing the degree of flow restriction in said flow path, respectively.

49. The nasal interface of any one of claims 1 to 48, wherein the gases manifold comprises an opening at a wall approximately opposite the gases inlet of the manifold and/or approximately opposite the second base of the second prong.

50. The nasal interface of claim 49, wherein the opening comprises one or a plurality of apertures.

51. The nasal interface of claim 50, wherein the number and diameter of said apertures are configured to provide a defined pressure drop.

52. The nasal interface of any one of claims 49 to 51, wherein the opening in the wall of the manifold is pneumatically connected to a component configured to provide a defined pressure drop.

53. The nasal interface of claim 52, wherein the component is at least one of a porous medium, a nozzle, a pressure-relief valve, an auxiliary tube, or a bubble CPAP bubbling chamber.

54. The nasal interface of any one of claims 1 to 53, wherein an axis of the gases inlet is co-axial relative to an axis of at least one of the first prong or second prong.

55. The nasal interface of any one of claims 1 to 53, wherein the angle of the axis of the gases inlet is perpendicular relative to an axis of at least the first prong or second prong.

56. The nasal interface of any one of claims 1 to 55, wherein the gases manifold comprises a second gases inlet.

57. The nasal interface of any one of claims 1 to 56, wherein the nasal interface comprises an auxiliary gases inlet to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

58. The nasal interface of claim 57, wherein the auxiliary gases inlet terminates in the first prong or the second prong.

59. The nasal interface of claim 57 or 58, wherein the auxiliary gases inlet is in fluid communication with an auxiliary gases conveying conduit.

60. The nasal interface of any one of claims 57 to 59, wherein at least one of the gases inlet or gases conveying conduit comprises a lumen with a first internal cross-sectional area and at least one of the auxiliary gases inlet or auxiliary gases conveying conduit comprises a lumen with a second internal cross-sectional area.

61. The nasal interface of claim 60, wherein the one or both of the first internal cross- sectional area and the second internal cross-sectional area are substantially circular.

62. The nasal interface of claim 61 or claim 62, wherein the first internal cross- sectional area and the second internal cross-sectional area are different.

63. The nasal interface of claim 63, wherein second internal cross-sectional area is smaller than an internal cross-sectional area of the first prong or second prong.

64. The nasal interface of claim 59, wherein the gases conveying conduit and the auxiliary gases conveying conduit are disposed on the same side of the manifold chamber.

65. The nasal interface of any one of claim 59, wherein the auxiliary gases conveying conduit is positioned in the gases conveying conduit.

66. The nasal interface of claim 59, wherein at least one of the gases inlet or the gases conveying conduit comprises a first length and at least one of the auxiliary gases inlet or the auxiliary gases conveying conduit comprises a second length.

67. The nasal interface of claim 66, wherein the first length and the second length are unequal to cause the asymmetrical flow of gases at the first prong and the second prong.

68. The nasal interface of claim 66 or claim 67, wherein the first length is longer than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

69. The nasal interface of claim 66 or claim 67, wherein the first length is shorter than the second length to cause or contribute to the asymmetrical flow of gases at the first prong and the second prong.

70. The nasal interface of claim 59, wherein the gases conveying conduit is in communication with a first gases flow and the auxiliary gases conveying conduit is in communication with a second gases flow.

71. The nasal interface of claim 70, wherein the first gases flow has a different flow rate to the second gases flow.

72. The nasal interface of claim 70 or claim 71, wherein a resultant flow direction between the gases manifold and the first gases flow is a different flow direction to a resultant flow direction between the gases manifold and the second gases flow.

73. The nasal interface of any one of claims 70 to 72, wherein one of the first or second gases flow is a suction flow.

74. The nasal interface of any one of claims 70 to 73, wherein a gas pressure of the first gases flow is different to a gas pressure of the second gases flow.

75. The nasal interface of claim 74, wherein a negative gas pressure relative to ambient is formed by the first gases flow or second gases flow.

76. A nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; and a gases manifold comprising: a manifold chamber; a first gases inlet; and a second gases inlet, wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, wherein the nasal interface is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

77. The nasal interface of claim 76, comprising at least one of:

(i) a first prong element positioned within the first prong;

(ii) a second prong element positioned within the second prong;

(v) a second gases inlet element positioned at the second gases inlet to the gases manifold, wherein the first prong element, second prong element, manifold element, first gases inlet element and/or second gases inlet element are each configured to increase the resistance to a flow of gases entering said respective element to cause the asymmetrical flow of gases at the first prong and the second prong.

78. A nasal interface comprising: a first prong and a second prong; a gases manifold comprising a manifold chamber and a gases inlet, the gases inlet is, or is configured to be, in fluid communication with a gases- conveying conduit; and at least one flow-directing element formed as part of at least one of the manifold chamber, gases inlet or gases-conveying conduit, wherein the at least one flow-directing element is configured to direct a flow of gases to one of the first prong or second prong to create an asymmetric flow of gases.

79. The nasal interface of any one of claim 78, comprising at least one of:

(i) a first prong element positioned within the first prong;

(ii) a second prong element positioned within the second prong;

(iii) a manifold element positioned in the manifold chamber and between the first base of the first prong and the second base of the second prong; wherein the first prong element, second prong element and/or manifold element are each configured to increase the resistance to flow of a flow of gases entering said respective element.

80. A nasal interface comprising: a first prong having a first base and a first terminal end; a second prong having a second base and a second terminal end; a gases manifold; a first gases inlet; and an auxiliary gases inlet, wherein the first gases inlet and the second gases inlet are in fluid communication with a first gases conveying conduit and a second gases conveying conduit, respectively, wherein the nasal interface is configured to cause an asymmetrical flow of gases at the first prong and the second prong.

81. A patient interface comprising the nasal interface according to any one of claims 1 to 80.

82. A respiratory therapy system comprising: a respiratory therapy apparatus comprising: a controller; a blood oxygen saturation sensor; an ambient air inlet; an oxygen inlet; a valve in fluid communication with the oxygen inlet to control a flow of oxygen through the oxygen inlet; and a gases outlet; wherein the controller is configured to control the valve based on at least one measurement of oxygen saturation from the blood oxygen saturation sensor; and a patient interface according to claim 81.