GB2633300A

GB2633300A - Negative pressure ventilator

Info

Publication number: GB2633300A
Application number: GB2313078.4A
Authority: GB
Inventors: Jordan Evans Adam
Original assignee: Portsmouth Aviation Ltd
Current assignee: Portsmouth Aviation Ltd
Priority date: 2023-08-29
Filing date: 2023-08-29
Publication date: 2025-03-12
Also published as: WO2025046231A1; GB202313078D0

Abstract

A negative pressure ventilator, otherwise known as an iron lung, comprising a patient enclosure 100 defining an internal space arranged to enclose the torso of a patient. The pressure in the internal space is controllable, and the enclosure comprises a base 13, a top part 5 which is detachably connectable onto the base, and two distal ends 105. Each of the distal ends are provided with an aperture 18, (120, Fig 6), and at least one of the distal ends comprises an end window 16 which allows a patient a line of sight to view into the internal space. The top part may also comprise a window 7, permitting viewing into the internal space of the enclosure. The top window 7 and end window 16 may be arranged to provide a line of sight from the top window through the end window to allow viewing of a patient’s head/face.

Description

NEGATIVE PRESSURE VENTILATOR

Technical Field

The present invention relates to negative pressure ventilators.

Background

Negative pressure ventilators are devices which help patients who are in respiratory distress or experiencing difficulties to breath. Such devices comprise an enclosure, located outside of a patient's body, and the pressure inside the enclosure is controlled so as to cause the torso to experience a varying pressure including sub-atmospheric pressures.

Negative pressure ventilation is mechanical ventilation in which negative pressure is generated on the outside of the patient's chest and transmitted to the interior to expand the lungs and allow air to flow in. The principle of negative pressure ventilation is that inspiration is initiated by an intermittent negative pressure produced outside the thorax.

We have devised various novel improvements in relation to negative pressure ventilators.

Summary

According to a first aspect of the invention there is provided a negative pressure ventilator comprising a patient enclosure, and the enclosure is a structure which defines an internal space which is arranged to enclose the torso of a patient, and the pressure in the internal space is controllable, and the enclosure comprises a base, two distal ends and a top part which is detachably connectable onto the base, each of the distal ends provided with an aperture, wherein, at least one of the distal ends comprises an end window which allows a patient a line of sight to view into the internal space.

Only one distal end of the enclosure may be provided with an end window.

A distal end which is arranged to receive the neck of a patient may be the distal end which is provided with the end window.

The top part may comprise a top window, which permits viewing into the internal space of the enclosure. The top window and the end window may be arranged such as to provide a line of sight from the top window through the end window to allow viewing of a patient's head/face. The top window may be provided on an upper region of the top part.

The end window may be provided above the aperture of the distal end which is configured to receive the neck of a patient.

The end window may be provided at an upper region of a distal end wall.

The end window may be of curved or arcuate shape.

The end window may occupy less than fifty percent of the area of the end wall.

Each distal end may comprise a distal end wall.

One distal end may be configured to receive a neck of a patient, and the other distal end may be arranged to receive a hip region of a patient. By hip region we include a region between and including waist and upper legs.

The patient enclosure, in use, may be arranged to contain the arms of a patient, as well as the torso.

The patient enclosure, in use, may be arranged to allow a patient's head and legs to protrude through respective distal ends.

The enclosure, in use, may be configured to contain the shoulders of a patient.

The enclosure may comprise gas/fluid porting which allows connection to a pump which is controllable to determine pressure within the internal space. The gas/fluid porting may comprise one or more fluid pathways which extend between an external part of the enclosure and the internal space of the enclosure.

The base may be provided with the gas/fluid porting for connection to a pump assembly which is arranged to remove air from the internal space of the enclosure.

The enclosure may be arranged to provide a sealed space (i.e. the internal space) around the enclosed body region(s), in which the pressure thereof is controllable.

The patient enclosure body may be arranged to seal at the neck region and at the hip region of a patient.

The top part may be of substantially domed or curved shape.

The top part may comprise a portion which is of substantially curved external shape which extends between end walls of the top part.

The top part may be wholly removable from the base.

The top part may be detachably connectable to the base by way of multiple spaced-apart fasteners. Each of the fasteners may be termed a clip.

The base may comprise a floor portion and surrounding walls which extend upwardly from a periphery of the floor portion. The surrounding walls may support the top part. The base may comprise a mattress (or other type of patient support structure) which, in use, is arranged to support the torso of a patient. The floor and walls of the base may define a volume which is arranged to receive the mattress/support structure.

The base may be provided with part of a periphery of each of the neck aperture and the torso aperture (which may be a minor portion of the overall extent of each aperture).

The base may comprise one or more openings/ports which are configured to allow routing of medical lines and monitoring cables into and out of the internal space of the enclosure.

An external surface of the top part may be provided with one or more lifting handles.

which facilitate the lifting of the top part from and the placement of the top part on the base. Two or more lifting handles may be provided on each (lateral) side region of the top part.

At least one handle is provided internally of the interior space of the enclosure, and is arranged to allow a patient to grip the same and pull themselves upwards, within the space. This may allow a user to reposition their torso within the internal space of the enclosure, for example, for improved comfort.

The at least one handle may be provided as a singular item, such as a bar, or two (or more) handles may be provided. Where two handles are provided, and there may be a handle for a left hand of the patient and a handle for a right hand of the patient. Where a single, elongate handle is provided, this may extend transversely of a length dimension of the enclosure. The length of such a single, elongate handle may be such as to allow a patient to use both hands to grip the same. Where two (or more) handles are provided they may be orientated either substantially parallel to the length dimension of the enclosure, or transversely to the same.

The at least one handle may be attached to the top part of the enclosure.

The at least one handle may be secured to an internally facing surface of an upper region of the top part of the enclosure.

The at least one handle may be such that it can support at least part of the weight of a patient.

The at least one handle may be secured to a roof of the enclosure.

The at least one handle may be viewed as an internal support.

The enclosure may be provided with at least two arm ports, which allow access into the internal space externally of the enclosure (for example, by a caregiver, a clinician, a medical professional or a relative of the patient).

D

Each of the arm ports may be provided with a closure which can be set in a closed position in which the respective port is closed, and in an open position in which allows access to the port.

Each closure may be pivoted/hinged, and thereby moved to an open position and to a closed position. A latch (or other typo of locking mechanism or device) may be provided for each closure to secure the respective closure in the closed position, and to allow release so that the closure can be moved from a closed position to an open position. A latch which is common to both closures may be provided which is arranged to secure both closures in closed positions.

Each arm port may comprise a seal which is located in a respective aperture of the enclosure.

Each seal may be arranged to be replaceable, that is detachably secured to the aperture. The seal may be configured to push-fit into a respective aperture formed in a wall, which may be a side wall, of the enclosure.

Each seal may be held in place in the aperture of the enclosure by a retainer. The retainer may be common for two seals, or a respective retainer may be provided for each seal. The retainer may comprise a component, which, in a retaining condition, holds the seal in place. The retainer may clamp the seal between itself and a wall of the enclosure in which the, or each, aperture is provided. The retainer may comprise a plate, and the plate may be pivotably mounted to a retaining position in which the, or each, seal is secured in place, and a release position in which the, or each, seal can be removed. The retainer in a retaining position is configured to bear against the or each seal. One or more latches or locks may be provided which serve to secure the retainer in the retaining condition. Where the retainer is a plate, this may be of curved shape/form. The retainer may comprise an aperture the size and shape of which is complementary to the seal. In the (seal) retaining condition, the periphery of the or each seal and the retainer may be sandwiched between the closure and the wall of the enclosure.

The seal may comprise an aperture which is arranged to allow an arm to pass therethrough. The seal may comprise a seat, which is provided at the periphery of the seal, which seat is arranged to locate on a portion of the enclosure which surrounds the aperture. The seal may comprise a lip or flange which extends inwardly of the seal. The innermost portion of the lip may define the aperture, through which an arm is received. The lip of the seal may be resiliently deflectable. The laterally outer portion of the se& may have a greater (cross-sectional) thickness than the lip. The seal may of substantially circular shape.

The seal may be such that it is arranged to seal against an arm inserted therethrough and so substantially ensure a pressure differential between the internal space and the atmospheric pressure externally of the enclosure.

There may be provided two arm ports on a side region of the enclosure Two hand ports may be provided on each of opposed lateral sides of the enclosure.

The arm ports may be provided in the top part of the enclosure.

There may be provided a garment attachable to the upper leg region of a patient which comprises two leg portions, which in use receive upper leg regions of a patient, and an upper portion which is configured to receive the hip region of the patient, and the waist portion sealingly connectable to a distal end aperture of the enclosure Free ends of the leg portions may be provided with respective fasteners which allow the same to the secured around the legs of the patient, and preferably this is such so as to form a seal (to substantially prevent atmospheric air entering the internal space of the enclosure). The fasteners may be of hook-and-loop type, for example Velcro® material, but other types of fastener can also be employed.

The garment may be a step-in type garment.

Neoprene 'trunks' for sealing lower body with top unit.

According to another aspect of the invention there is provided a negative pressure ventilator system comprising the patient enclosure of the first aspect of the invention, and a pump assembly, wherein the pump assembly is provided in a housing, and the housing comprises an uppermost surface which has a footprint to receive and support the enclosure assembly.

The footprint of the uppermost surface of the housing may substantially correspond to the footprint of the base of the enclosure.

The footprint of the uppermost surface of the housing may be larger than the footprint of the base of the enclosure.

The housing may be arranged to secure the enclosure in position on the uppermost surface. The housing may comprise one or more attachment points to allow the enclosure to be secured in position on the housing. One or more straps and/or clips may be provided, which connect to the enclosure and to the attachment points.

According to another aspect of the invention there is provided a negative pressure ventilator system comprising the patient enclosure of the first aspect of the invention, and a pump assembly, wherein the pump assembly is provided in a housing, and wherein the housing comprises a number of side walls, and at least one of the side walls is provided which access to a replaceable air filter.

The at least one side wall may be provided with a cover which allows access to a replaceable filter space, located internally of the housing. The cover may be a screw-fit or push-fit into, or hinged to, a side wall of the housing.

Multiple different side walls of the housing may each be provided with access to a respective filter.

Compressor filter removable from side panel of base unit.

One aspect of the invention is a negative pressure ventilator comprising a patient enclosure, and the enclosure is a structure which defines an internal space which is arranged to enclose the torso of a patient, and the pressure in the internal space is controllable, and the enclosure comprises a base, two distal ends and a top part which is detachably connectable onto the base, each of the distal ends provided with an aperture, wherein at least one handle is provided internally of the interior space of the enclosure, and is arranged to allow a patient to grip the same and pull themselves upwards, within the space.

One aspect of the invention is a negative pressure ventilator comprising a patient enclosure, and the enclosure is a structure which defines an internal space which is arranged to enclose the torso of a patient, and the pressure in the internal space is controllable, and the enclosure comprises a base, two distal ends and a top part which is detachably connectable onto the base, each of the distal ends provided with an aperture, wherein the enclosure may be provided with at least two arm ports, which allow access into the internal space externally of the enclosure, and each arm port comprises a seal which is located in a respective aperture of the enclosure, an each seal may be arranged to be replaceable, that is detachably secured to the aperture.

According to a further aspect of the invention there is provided a negative pressure ventilation system or apparatus for the treatment of patients with respiratory distress, which comprises: a patient enclosure; a pump assembly; a controller; connecting hoses (for evacuating air from internal space defined by the enclosure); and ancillary equipment (such as one or more of: neck seals, torso seals, a pressure sensing line, a mattress assembly, a control cable and a power cable).

Any of the above aspects of the invention may comprise, either singularly in combination, one or more features disclosed above, in the description and/or as shown in the drawings (even though any feature may be shown but not described). This disclosure also includes that any features disclosed herein can be used to supplement any of the above aspects, and for such purpose none of those features, individually, is inextricably linked to any other such feature, notwithstanding that multiple features may be disclosed in the context of a particular embodiment in relation to other features.

Brief Description of the Drawings

Various embodiments now described, by way of example only, with reference to following drawings in which: Figure 1 is a perspective view of a negative ventilation system, Figure 2 is a perspective view of an enclosure of the negative ventilation system of Figure 1, Figure 3 is a plan view of a side of the enclosure of Figure 2, Figure 4 is and end view of the enclosure of Figure 2 in which various components of an arm port assembly are shown in an exploded view, Figure 5 is a perspective view of the enclosure, Figure 6 is an opposite perspective view, in relation to Figure 5, Figure 7 is an enlarged view of a distal end of an enclosure, Figure 8 is a view of the enclosure to which is attached a sealing garment, Figure 9 is view of internal features of the enclosure, Figure 10 is a perspective view of an enclosure located on a pump assembly, Figure 11 is an enlarged view of strap assemblies securing the enclosure to the pump assembly, Figure 12 is an exploded side elevation of a pump assembly, Figures 13 and 14 show access provided for a first filter in the pump assembly, Figures 15 and 16 show access provided for a first filter n the pump assembly, and Figure 17 is a view of an enclosure in use, in which a backrest of a bed is in an elevated position.

Detailed Description

A novel negative pressure ventilator apparatus and system is now described, as well as various novel embodiments thereof, used for treating patients who are in respiratory distress.

In overview, the system, as shown in Figure 1, comprises a patient enclosure 100, a pump assembly, a controller, connecting hoses/conduits, and various ancillary equipment, such as neck and torso seals, a pressure sensing line, a mattress assembly, a control cable and a power cable. The system, in particular, comprises a domed enclosure body which is arranged to enclose the chest and torso of a patient. The enclosure envelops the torso of the patient, with seals at the neck region and hip region of the patient, respectively. In use, a pressure gradient is created by generating a sub-atmospheric pressure outside the chest and abdomen within the internal space of the enclosure. This pressure differential brings about an increase in the diameter of the chest and causes descent of the diaphragm. Fresh gas therefore moves down a pressure gradient from the upper airway to the alveoli. Expiration is passive and driven by the elastic recoil of the lungs, chest wall and diaphragm. The disclosed apparatus and system can be used to generate a Continuous Negative Extrathoracic Pressure (CNEP) and to provide Negative Pressure Ventilation (NPV).

With reference to Figure 2, the enclosure 100 comprises a base 13 and a top part/lid 5. The enclosure 100 is dimensionally configured to interface with a standard hospital bed and to be securely held in place on a hospital bed.

The enclosure 100 comprises four scaled arm ports 10, two on each side of the lid 5, which allow the patient to be cared for without disrupting the respiratory treatment. The ports 10 allow the arms of a healthcare professional to be inserted through a rubber seal, maintaining the internal pressure at the same time. The ports also provide the benefit of personal contact with family members such as enabling the ability to hold hands for mental well-being of the patient. The ports 10 each comprise an aperture which is formed in a wall of the lid 5, a seal II which locates in a respective aperture 10, and a seal closure l la. Each of the seals 11 is retained in position by way of a (curved) retainer plate 11b, which when in a retaining position bears against the seals. Each of the retainer plates 1lb is provided with an aperture which is dimensioned so as to bear against the seals. The retainer plates IIb are attached to the lid 5 by way of two hinges, 11c, which allow each plate to be moved from a seal retaining position to a release position. Latches 8 enable each retainer plate to be held in a retaining position, and in such position the periphery of seals 11 arc sandwiched or clamped between the retainer plate and a side wall of the lid. As perhaps best seen in Figure 3, each of the retaining plates services both arm ports on each side. The seals 11 arc of circular shape and having a periphery which is seated on the wall of the lid 5, and a resiliently deflectable lip which is inward of the periphery. Each of the arm port apertures, or specifically the central aperture provided by each of the seals can be closed off or 'shut' when not in use by way of the respective closures I I a.

Each of the closures lla is pivotally mounted by respective hinges 11d, which are themselves mounted onto the retainer plate 1 lb. Each of the closures l la is provided with a respective latch which serves to retain the cover in a closed position and so prevent access through an ann port into the internal space. The seals 11 are removable from their positions in the lid 5, and so enable them to be cleaned, replaced or serviced.

The base 13 comprises a floor and four surrounding walls. At one distal end of the base 13 a number of apertures are provided, as are shown in various figures, including Figure 2 and Figure 6. Each of the apertures provides a pathway into the internal space of the enclosure. Two ports 20 are arranged to receive a respective hose or conduit, which also connect to the pump assembly, for removing air from the internal space of the enclosure 100, and thereby enable control of the negative pressure therein.

The same distal end of the base 13 also comprises two sets of access slots 19. The access slots 19 are provided to route medical lines and monitoring cables into / out of the internal space of the enclosure. Disposable foam seals (not illustrated) which reside in the slots provide the sealing around the lines and cables.

The base 13 contains a mattress assembly (not illustrated), to provide support to a patient receiving treatment.

The enclosure 100 comprises two distal ends 105. The distal end 105 which is shown in Figure 2 is provided with an aperture which is arranged to receive the neck of a patient. In Figure 2, the neck aperture has a removable blank 18 therein, these are used for system testing, storage and transit and are secured in place to block the aperture with over-centre clips. A blank 1, as shown in Figure 5, is used to block/cover the torso aperture, which is located in an opposite distal end of the enclosure.

With reference to Figure 7, the neck aperture 120 can be seen to be defined by both an end wall of the lid 5 as well as an end wall of the base 13, with the larger extent of the aperture provided by the lid end wall. The torso aperture at the opposite distal end of the enclosure is similarly formed (by both the base and the lid).

The distal end 105 in which the neck aperture 120 is provided comprises an end window 16. The end window 16 allows for sight for a medical professional of the patient's face from above the unit (through an upper window which is described in more detail below). The end window 16 also provides the patient with a visual awareness of what is happening in the vicinity, for mental well-being, and the ability to have a line of sight into the internal space of the enclosure, and so enable the use electronic devices or read whilst undergoing treatment. The end window 16 is of curved shape, but could be of other shapes.

The lid 5 comprises an upper or top window 7, which is located at an upper region of the lid 5. This principally allows a line of sight into the internal space, but as mentioned above also, in conjunction with the end window, allows visibility for both patient for health professional, caregiver, etc. A thermometer 6 is fixed to the top window,to display the temperature within the enclosure.

The lid 5 can be secured to the base 13 by way of four latch mechanisms 12, and the lid is supported on the upstanding peripheral walls of the base 13 when attached. The lid 5 can be lifted into and out of position using handles 3, which are located on an external surface of the lid.

For each of the neck aperture and the torso aperture there is a sealing garment, which can be secured to the margin or interface of the aperture and to the patient. For example, the neck aperture 120 is provided with an interface 17 which is arranged to detachably receive a neck seal garment. The garment is of open-ended tubular form, with one end thereof attachable to the interface 17 and the other end securable around the neck of a patient. In more detail, the neck seal garment comprises a neoprene (or similar material) tube with an elastic cord to attach to the enclosure 100 and hook-and-loop type fastener (such as Velcro® fasteners) to wrap around the neck of a patient. The garment is placed over the head of the patient with the elastic cord lowermost and the Velcro® is adjusted until comfortably snug. The garment then mounts over the interface 17 of the enclosure.

Similarly, at the opposite end of the enclosure 100, there is provided an interface 2 which is a periphery of the torso aperture 121. The interface 2 is arranged to receive a garment 50, as shown in Figure 8. The garment 50 may be in form of trunks/shorts, having a part which encloses the hip region of a patient, and two leg portions 51 which receive each of a patient's legs. At the distal end of each of the legs 51, there is provided a fastener 52, which allows each of the distal ends to be secured around a respective upper leg region of a patient. The garment 50 may be made of a flexible and stretchable material. When fitting, the garment is stepped into. That part of the garment which is to be attached to the interface 2 comprises an elastic cord, which ensures retention when attached to the interface 2. The fasteners 52 are then tightened so that the leg portions 51 seal with the patient's legs so as to substantially prevent any pathway for gas from atmosphere into the internal space.

As shown in Figure 9, the enclosure 100 is provided with two handles 30 which are located within the internal space. Each of the handles 30 is attached to an upper inner surface of the lid by way of two brackets. The handles 30 allow a patient to grip the same, one handle for each hand, and to lift themselves to reposition their torso within the internal space, for example to move to a more comfortable position.

Reference is now made to Figure 10, which shows the enclosure 100 on top of the pump assembly 200. The pump assembly 200 comprises a housing having four side walls which extend upwardly from a floor and an uppermost surface 201. In Figure 10, the enclosure 100 is supported on the uppermost surface, 201. it can be seen from Figure 10 that the aerial footprint of the uppermost surface 201 substantially matches the footprint of the enclosure 100. The enclosure 100 is held in position on the pump assembly 200 by way of the strap assemblies 70 which each comprise a length of strap or webbing 71, and an attachment feature 72, of hooked form, shown in Figure I I. The attachment feature 72 is located under a handle 210 of the pump assembly. The strap assembly 70 is secured to the enclosure 100 at fixing point 73. A free end of the strap can be tightened so as to achieve a secure fastening of the enclosure assembly onto the pump assembly. The strap assembly comprise a buckle 74 which allows for loosening and tightening. Two such strap assemblies are used on opposite sides. In this way, the enclosure assembly becomes practically immoveable on the pump assembly, when the system needs to be moved or when it is not in use. (It will be appreciated that Figure 10 omits to show the strap assemblies.) One-and-the-same strap assemblies 70 which are used to secure the enclosure 100 to the pump housing are also intended to secure the enclosure to a (hospital) bed. The strap system is designed to ensure it is adjustable to interface with a number of different bed types in use in healthcare environments.

Referring now to Figures 12 to 16, the pump assembly 200 comprises side walls which allow access to two filters, so that they can conveniently be replaced/serviced. Each of the filters is designed to remove particulate from air. The pump assembly 200 provides the motive force for achieving the sub-atmospheric pressure within the enclosure. Air is drawn through valves and filters by a vacuum pump (located within the housing 200). High efficiency particulate air (HEPA) filters ensure the internals of the system remain free from contamination. Opposite side walls of the housing 200 of the pump assembly are provided with external access to respective filters. The housing 200 comprises a hinged panel 231 for maintenance access to an inlet panel filter 230, which is mounted in use in a space 232. The housing 200 also comprises a screw-fit cover 241 for access to a pump inlet radial filter 240 The housing 200 further comprises a removable panel 260, which allows access to the innards of the pump assembly, and two connector ports 250, which couple with air hoses to form a circuit to evacuate air from the internal space of the enclosure 100.

The uppermost surface 201 may be removable and so also allow access to the interior space of the pump assembly.

The controller is connected to the pump assembly by electrical cables, and can bring about required operational mode, as input by a user to a user interface of the controller. Pressure within the enclosure is continuously monitored via a pressure sensing line to the controller from the enclosure 100.

The above described apparatus and system provide various important advantages. For example, encapsulating the entire torso of a patient circumferentially, including the diaphragm, achieves a higher efficiency tidal volume level and is therefore more efficient than cuirass devices and provides a significantly higher clinical benefit. The device weight is such that it can be easily manoeuvred and positioned, and the patient enclosure lid lifted easily. This allows good access to the patient and easy management of any nursing requirements. Furthermore, if required, the enclosure can be used with the patient in the prone position. The enclosure not being the full length of a bed enables backrest elevation for improved comfort and reduction in bed sores, as shown in Figure 17.

In a variant embodiment, the lid 5 may be mounted to the base by a hinge, and thereby can be moved from an open position to a closed position.

in another variant embodiment, the lid 5 may be substantially transparent, that is the majority of the surface area of the structure.

Claims

CLAIMS1. A negative pressure ventilator comprising a patient enclosure, and the enclosure is a structure which defines an internal space which is arranged to enclose the torso of a patient, and the pressure in the internal space is controllable, and the enclosure comprises a base, two distal ends and a top part which is detachably connectable onto the base, each of the distal ends provided with an aperture, wherein, at least one of the distal ends comprises an end window which allows a patient a line of sight to view into the internal space.
2. A negative pressure ventilator as claimed in claim 1 in which only one distal end of the enclosure is provided with an end window.
3. A negative pressure ventilator as claimed in claim I or claim 2 in which a distal end which is arranged to receive the neck of a patient is the distal end which is provided with the end window.
4. A negative pressure ventilator as claimed in any preceding claim in which the top part comprises a top window, which permits viewing into the internal space of the enclosure, and the top window and the end window is arranged such as to provide a line of sight from the top window through the end window to allow viewing of a patient's head/face.
5. A negative pressure ventilator as claimed in any preceding claim in which comprises at least one handle which is provided internally of the interior space of the enclosure, and is arranged to allow a patient to grip the same and pull themselves upwards, within the space.
6. A negative pressure ventilator as claimed in any preceding claim comprising at least two arm ports, which allow access into the internal space externally of the enclosure, and each arm port comprising a seal which is arranged to seal around an arm which is inserted into the internal space, and each seal is arranged to be replaceable
7. A negative pressure ventilator as claimed in claim 6 which comprises one or more seal retainers which arc arranged to secure the seals in position, and the retainer can be moved to a release condition which allows for one or more of the seals to be removed.
8. A negative pressure ventilator as claimed in any preceding claim which comprises a garment which comprises two leg portions, which in use receive upper leg regions of a patient, and an upper portion which is configured to receive the hip region of the patient, and the upper portion sealingly connectable to a distal end aperture of the enclosure.
9. A negative pressure ventilator as claimed in claim 8 in which free ends of the leg portions are provided with respective fasteners which allow the same to the secured around the legs of the patient, and preferably this is such so as to form a seal to substantially prevent atmospheric air entering the internal space of the enclosure.
10. A negative pressure ventilator system comprising the patient enclosure of any of claims I to 9, and a pump assembly, wherein the pump assembly is provided in a housing, and the housing comprises an uppermost surface which has a footprint to receive and support the enclosure assembly.
11. A negative pressure ventilator system as claimed in claim 10 in which the footprint of the uppermost surface of the housing substantially corresponds to the footprint of the base of the enclosure.
12. A negative pressure ventilator system as claimed in claim 10 or claim II, in which the housing is arranged to secure the enclosure in position on the uppermost surface, and the housing and the enclosure comprising one or attachment points to allow the enclosure to be secured in position.
13. A negative pressure ventilator system as claimed in claim 12 in which one or more straps and/or clips are provided, which connect to the enclosure and to the attachment points.
14. A negative pressure ventilator system as claimed in any of claims 10 to 13 in which one or more external side walls of the housing is provided with access to an air filter, which allows the same to removed and/or installed.