[go: up one dir, main page]

WO2007033074A2 - Ensemble de soupape de purge de la pression sanguine - Google Patents

Ensemble de soupape de purge de la pression sanguine Download PDF

Info

Publication number
WO2007033074A2
WO2007033074A2 PCT/US2006/035302 US2006035302W WO2007033074A2 WO 2007033074 A2 WO2007033074 A2 WO 2007033074A2 US 2006035302 W US2006035302 W US 2006035302W WO 2007033074 A2 WO2007033074 A2 WO 2007033074A2
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
pressure chamber
bleed valve
cuff
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2006/035302
Other languages
English (en)
Other versions
WO2007033074A3 (fr
Inventor
Allan I. Krauter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Welch Allyn Inc
Original Assignee
Welch Allyn Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/225,744 external-priority patent/US20070060825A1/en
Application filed by Welch Allyn Inc filed Critical Welch Allyn Inc
Priority to JP2008531217A priority Critical patent/JP2009507610A/ja
Priority to EP06803325A priority patent/EP1931244A2/fr
Publication of WO2007033074A2 publication Critical patent/WO2007033074A2/fr
Publication of WO2007033074A3 publication Critical patent/WO2007033074A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/021—Measuring pressure in heart or blood vessels
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/0235—Valves specially adapted therefor

Definitions

  • This invention relates generally to the field of blood pressure measurement devices and, more particularly, to a nearly constant cuff pressure decrease rate valve for use in either manual or electronic blood pressure measurement devices.
  • Blood pressure measurement devices also referred to as sphygmomanometers, of the type commonly used to measure arterial blood pressure, include an inflatable sleeve, commonly referred to as a cuff, adapted to fit around a limb, e.g. an arm or leg, of a patient.
  • the cuff includes an interior chamber that is in fluid communication with a device for selectively inflating the interior chamber of the cuff with pressurized air.
  • a gage is operatively connected in fluid communication with the interior chamber of the cuff for monitoring the air pressure within the cuff.
  • a bleed valve is also operatively connected in fluid communication with the interior chamber to permit selective depressurizing of the interior chamber when it is desired to deflate the cuff.
  • the interior chamber of the cuff is connected through a length of flexible tubing to a pneumatic bulb, hi operation, the cuff is fitted, e.g. wrapped, about the arm of the patient and, once so positioned, the cuff is inflated by squeezing the pneumatic bulb to force air through the tubing into the interior chamber of the cuff.
  • the cuff is deflated by opening the bleed valve to allow the pressurized air within the interior chamber of the cuff to vent slowly to atmosphere.
  • a stethoscope is positioned under the cuff and over the patient's brachial artery to monitor the patient's arterial pulses as the cuff deflates, thereby allowing the systolic and diastolic blood pressures to be determined by listening for the Korotkoff sounds.
  • the systolic and diastolic blood pressure can also be measured oscillometrically by detecting the minute changes in the cuff pressure due to flow of blood through the brachial artery.
  • This oscillometric measurement also utilizes an inflatable cuff and generally employs one or more pressure sensing devices, such as a transducer, to monitor the pressure within the interior chamber of the cuff.
  • the transducer monitors both the average pressure in the cuff and the minute changes in the cuff pressure due to flow in the patient's artery as the cuff deflates.
  • Electronic circuitry is provided that processes the signals from the pressure-sensing device and determines the systolic and diastolic blood pressures.
  • a motor driven pump is usually provided to inflate the cuff. However, the inflation can be produced via a pneumatic bulb.
  • a digital display is provided for displaying the systolic and diastolic blood pressures.
  • a typical vent valve has an air passage through which the flow of air may be adjusted by selectively restricting the flow area by manipulation of a thumbscrew. The thumbscrew is tightened down to fully close the vent valve passage when the cuff is being inflated.
  • the user manually turns the thumbscrew to slightly open the vent valve passage to initiate deflation of the cuff.
  • the user also monitors the patient's artery using a stethoscope to listen for the aforementioned Korotkoff sounds to detect when the systolic pressure and the diastolic pressure have been reached.
  • the user should follow the decrease in cuff pressure as registered on the pressure gauge and should continually adjust the vent thumb screw to increase the flow area through the vent valve passage as the pressure in the cuff decreases in an attempt to maintain a nearly constant bleed rate.
  • the user should maintain this rate within the desired rate range, while at the same time continuing to concentrate on listening for the characteristic Korotkoff sounds to detect the systolic and diastolic blood pressures. It is difficult to manually maintain the desired linear pressure decrease as the cuff deflates by adjusting a thumbscrew even under ideal conditions. It is even more difficult to do so when attempting to listen for the arterial sounds. Once the cuff pressure has dropped to the diastolic pressure point, the user must then further adjust the thumbscrew to fully open the vent passage, thereby providing a rapid final deflation of the cuff to ensure patient comfort.
  • An electronic blood pressure measurement apparatus can be designed with linear cuff pressure decrease.
  • Such an apparatus may comprise a valve that vents the interior chamber of the inflated cuff through a port whose flow area is controlled electronically.
  • the controller selectively opens the valve. This selective opening is needed to compensate for the airflow behavior of a fixed area port.
  • the vent flow rate varies as a function of the pressure differential across the port at any given time in the venting process.
  • the pressure differential that is, the difference between the air pressure within the interior chamber of the cuff and ambient pressure — also continuously decreases. Therefore, since the pressure differential across the vent port is continuously decreasing, the flow rate does not remain relatively constant to provide the desired 2-3 mniHg/sec rate during the deflation process, but rather continuously decreases.
  • the inflated volume of the pressure chamber of the cuff affects the bleed rate through a conventional fixed area orifice bleed valve.
  • a cuff for a large adult typically has a pressure chamber having a length of approximately 27 centimeters and a width of approximately 12.5 centimeters
  • a cuff for a small child typically has a pressure chamber having a length of approximately 13 centimeters and a width of approximately 5 centimeters.
  • the fact that the inflated volume of the adult cuff is many times as great as the inflated volume of the child cuff has a substantial impact upon the rate of pressure decrease in the respective cuffs for deflation through a bleed valve having a fixed flow area opening.
  • the larger volume cuff exhibits a slower pressure decrease rate at a given inflation pressure than the smaller volume cuff exhibits. As discussed above, this pressure decrease rate does not remain constant as the cuff deflates, but rather decreases as the cuff deflates due to the drop in pressure within the cuff.
  • Link discloses a pressurizing and depressurizing design for a blood pressure cuff with the objective of controlling the cuff inflation or deflation process at a substantially linear rate independent of the size of the cuff in use.
  • the disclosed device includes a housing defining an internal volume divided by a wall supporting a flexible diaphragm.
  • This division produces a control chamber and an active chamber, the wall and diaphragm forming a boundary therebetween.
  • the active chamber is in pneumatic communication with the blood pressure cuff and with a vent passage to ambient surroundings.
  • the control chamber is in pneumatic communication with the active chamber via an opening in the division wall, the opening forming pneumatic restrictor.
  • the flexible diaphragm moves in response to the pressure differential between the active chamber and the control chamber to selectively open and close the outlet from the active chamber to the vent passage.
  • air from the cuff passes into the active chamber causing the diaphragm to flex away from the vent passage and toward the control chamber, thereby opening the vent passage to allow air to vent from the active chamber to ambient surroundings.
  • an abrupt drop in cuff pressure can initially occur until the diaphragm responds sufficiently to cause closure of the vent port.
  • Such an abrupt decrease can be relatively large, in particular for small cuffs, and disruptive of the blood pressure measurement process.
  • a relatively large differential pressure may exist across the diaphragm while the air flows from the control chamber through the flow restrictor and into the active vent chamber to reduce the pressure differential.
  • the deflation process can not start properly until this pressure balancing is completed. Once the deflation process does begin, the initial deflation of the cuff proceeds slowly until the eventual linear steady state rate is achieved.
  • the time required to the pressurize the system is lengthened because air passing into the control chamber must first pass through the flow restrictor, which causes a time delay between the time the cuff is pressurized and the control chamber is pressurized to cuff pressure. If the user doesn't wait until the pressure in the control volume reaches that in the cuff, there is an abrupt decrease in cuff pressure (which can be large for small cuffs) when the closure valve is opened to start the cuff deflation process.
  • the diaphragm must be selected to have low inertia.
  • the diaphragm must also not require a high pressure differential across it to move the valve stem relative to the outlet vent opening through the operating range.
  • the diaphragm must also provide sufficient flow area at the outlet port so that rapid deflation of large cuffs is possible.
  • a bleed valve assembly for self-controlling the pressure change rate during the deflation of an inflated blood pressure cuff to facilitate the blood pressure measurement process.
  • the bleed valve assembly includes a bleed valve and a control valve operatively associated therewith.
  • the bleed valve defines an interior chamber that is sectioned into a first pressure chamber and a second pressure chamber by a first flexible diaphragm extending across the interior chamber of the bleed valve.
  • the first diaphragm provides a seal between the first pressure chamber on a first side of the first diaphragm and the second pressure chamber on a second side of the first diaphragm.
  • a second diaphragm sections the second pressure chamber from a third pressure chamber.
  • This third pressure chamber is on a second side of said second diaphragm, the first side of which is on the second pressure chamber.
  • a first vent passage having a regulated flow area outlet to ambient pressure from the first pressure chamber of the bleed valve, provides a flow path for venting the first pressure chamber to the exterior of the bleed valve.
  • a second vent passage opens from the second pressure chamber of the bleed valve to the third pressure chamber of the bleed valve and has a variable flow area.
  • a selectively positionable control valve is operatively associated with and connected in pneumatic communication with the three sections of the interior chamber of the bleed valve.
  • the control valve is positionable in a first position for equalizing the pressures in the three pressure chambers, in a second position for venting the blood pressure cuff through the first vent passage via the first pressure chamber and for venting the second pressure chamber to ambient pressure at a substantially constant pressure decrease rate through the second vent passage, and in a third position bypassing the bleed valve for rapidly venting the blood pressure cuff to ambient pressure or for rapidly decreasing the cuff pressure during a portion of the blood pressure measurement process.
  • the second flexible diaphragm is disposed within the interior chamber of the bleed valve in spaced relationship with the first diaphragm to establish the third pressure chamber.
  • the second pressure chamber extends between the first diaphragm and the second diaphragm, and the third pressure chamber lies on the opposite side of the second diaphragm.
  • the second diaphragm has a centrally located hole passing therethrough that provides pneumatic communication between the second pressure chamber and the third pressure chamber.
  • An axially elongated rod having a tapered distal tip is positioned within the hole in the second flexible diaphragm.
  • This pressure differential causes the second flexible diaphragm to move axially relative to the tapered distal tip, and in operative association with the tapered distal tip, to form a variable area opening between the second and third pressure chambers.
  • the axially elongated rod may be selectively positioned axially within the hole in the second flexible diaphragm to provide an annular orifice between the rod and the second flexible diaphragm having a desired maximum flow area when the second flexible diaphragm is in an unflexed state.
  • the tapered distal tip of the axially elongated rod is an extension of a rod that tapers linearly from a maximum cross-sectional area at its proximal base end to a minimum cross-sectional area at its distal end.
  • the selectively positionable control valve has a first port connected in pneumatic communication with the blood pressure cuff, the first pressure chamber of the bleed valve, and the air pump.
  • a second port is in pneumatic communication with ambient pressure.
  • a third port is in pneumatic communication with the third pressure chamber of the bleed valve and a fourth port is in pneumatic communication with the second pressure chamber of the bleed valve.
  • the control valve is positioned in a first position wherein the first, third and fourth ports are connected in pneumatic communication for pressurizing and equalizing the pressure within the first, second and third pressure chambers of the bleed valve.
  • the control valve is in a second position wherein the second port and the third port are connected in pneumatic communication with each other for venting the third pressure chamber to ambient pressure at a substantially constant bleed rate through the second vent passage. Also during this mode the first and fourth ports are closed. The first pressure chamber and the connected cuff are simultaneously vented to ambient pressure at a substantially constant pressure decrease rate through the first vent passage as is detailed hereinbelow.
  • the control valve is in a third position wherein the first port, the second port, and the fourth ports are connected in pneumatic communication, which rapidly vents the blood pressure cuff to ambient pressure.
  • a method for venting air from a blood pressure cuff inflated to a cuff pressure through a bleed valve at a relatively constant cuff pressure decrease rate that is independent of cuff size.
  • the method comprises the steps of: providing a first pressure chamber and a second pressure chamber within the bleed valve in pneumatically sealed relationship; pressurizing the first pressure chamber and the second pressure chamber to the cuff pressure; establishing air flow communication between the inflated cuff and the first pressure chamber; isolating the second pressure chamber from the cuff and establishing pneumatic communication between the second pressure chamber and ambient pressure; controllably venting air from the second pressure chamber at a relatively constant bleed rate in response to a pressure differential between the second pressure chamber and ambient pressure; and venting air from the first pressure chamber to ambient pressure in regulated response to a pressure differential between the first chamber and the second pressure chamber, whereby the pressure within the cuff decreases at a relatively constant cuff pressure change rate that is independent of the size of the
  • a variable area airflow opening is provided between the second pressure chamber and ambient pressure.
  • the area of the opening self-adjusts in response to the pressure differential between the second pressure chamber and ambient pressure, with the area of the opening increasing as the pressure differential between the second pressure chamber and ambient pressure decreases.
  • an air flow passage is provided between said first pressure chamber and ambient pressure and the flow area into the air flow passage is regulated in response to the pressure differential between the first pressure chamber and the second pressure chamber.
  • FIG. 1 is an elevation view, partly in section, of an exemplary embodiment of the bleed valve assembly of the invention positioned as during inflation of an associated blood pressure cuff;
  • FIG. 2 is an elevation view, partly in section, of the exemplary embodiment of the bleed valve assembly of the invention positioned as during controlled deflation of an associated blood pressure cuff;
  • FIG. 3 is an elevation view, partly in section, of the exemplary embodiment of the bleed valve assembly of the invention positioned as during rapid deflation of an associated blood pressure cuff;
  • FIG. 4 is an exploded elevation view showing the first diaphragm of
  • FIG. 5 is an exploded elevation view showing the second diaphragm of Figure 1 in its non-flexed position
  • FIG. 6 is an exploded elevation view showing the first diaphragm of
  • FIG. 7 is an exploded elevation view showing the second diaphragm of Figure 2 in its flexed position.
  • an exemplary embodiment of the bleed valve assembly 10 of the invention 10 includes a bleed valve 20 and a selectively positionable control valve 50 operatively associated the with bleed valve 20.
  • the bleed valve 20 includes a three-part housing 22 defining an interior chamber having a fixed internal volume, which is divided into three separate chambers by a pair of spaced apart flexible diaphragms 30 and 40.
  • Each of the flexible diaphragms 30 and 40 is a relatively thin disk having an annular portion 32, 42 and a centrally located, thimble-like portion 34, 44 that extends outwardly from the front side 31, 41 of the annular portion of the respective diaphragms.
  • the diaphragms 30 and 40 may be made from metal, such as copper, aluminum, tin or the like, or an elastoplastic material.
  • the diaphragms may also be made flat; i.e., with in-plane central discs replacing the thimble-like portions 34, 44.
  • the first flexible diaphragm 30 extends across the interior chamber of the bleed valve 20 and sections the interior chamber into a first pressure chamber 25 on the front side 31 of the first diaphragm 30 and a second pressure chamber 35 on the rear side 33 of the first diaphragm 30.
  • the first pressure chamber 25 is pneumatically sealed from the second pressure chamber 35 by the first diaphragm 30, which is supported on a pair of seals 12 and 14 extending circumferentially around the edge and on each surface of the first diaphragm 30.
  • the seals 12 and 14 are disposed in a land 23 in an upper end cap 26 of the housing 22, with the O-ring 12 disposed superadjacent the front side 31 of the first diaphragm 30 and the O-ring 14 disposed subadjacent the rear side 33 of the first diaphragm 30.
  • the second flexible diaphragm 40 extends across the second pressure chamber 35 of the bleed valve 20 to establish a third pressure chamber 45 on the rear side 43 of the second diaphragm 40.
  • the second diaphragm 40 is supported about its radially outward surfaces in a land 27 in a lower end cap 28 of the housing 22 between seals 16 and 17.
  • the seals 16 and 17 extend circumferentially around the edge and on each surface of the second diaphragm 40. Seals 16 and 17 are disposed superadjacent the front side 41 and subadjacent the rear side 43, respectively, of the second diaphragm 40, The seals 16 and 17 provide a pneumatic seal between the central pressure chamber 35 and the third pressure chamber 45.
  • the second diaphragm 40 has a centrally located hole 46, Figures 5 and 7, passing therethrough that provides a fluid flow path, establishing pneumatic communication between the second pressure chamber 35 and the third pressure chamber 45.
  • the second pressure chamber 35 which defines a reference volume, lies between the spaced apart diaphragms 30 and 40.
  • the first pressure chamber 25 is located on the front side of the first diaphragm 30.
  • the third pressure chamber 45 is located on the rear side of the second diaphragm 40.
  • the reference volume which remains substantially constant throughout the cuff deflation process, is relatively large in comparison to the respective volumes of the first and third pressure chambers.
  • the first pressure chamber 25 is also be referred to herein as the upper pressure chamber
  • the second pressure chamber 35 is referred to herein as the central pressure chamber
  • the third pressure chamber 45 is referred to herein as the lower pressure chamber.
  • the housing 22 of the exemplary embodiment of the bleed valve 20 includes a cylinder 24 having a central bore extending axially therethrough, the upper end cap 26 mounted to the upper end of the cylinder 24, and the lower end cap 28 mounted to the lower end of the cylinder 24.
  • the upper end cap 26 and lower end cap 28 are secured to the respective upper and lower ends of the cylinder 24 by at least two clamp screws 18 extending between the respective flanges of the end caps 26 and 28.
  • the aforementioned land 23, in which the first flexible diaphragm 30 is supported, is formed in the end cap 26.
  • the aforementioned land 27, in which the second flexible diaphragm 40 is supported is formed in the end cap 28.
  • the upper end cap 26 has a central bore extending therethrough that is internally threaded to receive an end fitting 60.
  • the end fitting 60 has an axially extending shaft having a threaded tip adapted to be threaded into the central bore of the end cap 26.
  • a circumferential seal 61 for example an O-ring seal, is disposed within the central bore of the end cap 26 to provide a seal between the internal surface of the central bore and the outer surface of the shaft of the end fitting 60.
  • the end fitting 60 has an axial bore 62 extending axially therethrough having an opening 64 into the upper pressure chamber 25.
  • the central bore 62 extending axially through the end fitting 60, forms a first vent passage for venting fluid from within the upper pressure chamber 25 directly to ambient pressure exteriorly of the bleed valve 20.
  • the outlet to the central bore 62 has a regulated flow area.
  • An elastomeric ring 66 such as for example an O-ring, is carried on the end face of the end fitting 60 and extends circumferentially about the outlet to the central bore 62.
  • the end fitting 60 is threaded into the central bore of the end cap 26 sufficiently far for the O-ring to contact and seal against the surface of the thimble-like outward projection 34 of the first flexible diaphragm 30.
  • the lower end cap 28 also has a central bore extending therethrough that is internally threaded to receive an end fitting 70.
  • the end fitting 70 has an axially extending threaded shaft adapted to be threaded into the central bore of the end cap 28.
  • the end fitting 70 has an axial bore 72 extending axially therethrough in which an axially elongated rod 80 is supported on an elastomeric bushing 71, for example a compression seal, which is disposed within the central bore of the end cap 28.
  • the bushing 71 not only provides support for the axially elongated rod 80, but also seals the region between the rod 80 and the surrounding interior wall of the central bore of the end cap 28 so that fluid does not leak therethrough from the third pressure chamber 45 to the ambient pressure environment exterior of the bleed valve 20.
  • the axially elongated rod 80 which need not be axisymmetrical or cylindrical, has a tapered tip 82, Figures 5 and 7, at its distal end.
  • the tapered tip may comprise a generally conical extension of the rod that tapers inwardly from a maximum diameter at its base end to a minimum diameter at its end. This taper need not be conical, and may be created by cutting through the rod at an angle.
  • the rod 80 extends axially through the end fitting 70 into the lower pressure chamber 45 so that the tapered tip 82 of the rod 80 is positioned within the hole 46, Figures 5 and 7, in the second flexible diaphragm 40.
  • the rod 80, in particular the tapered tip 82 of the rod 80, and the hole 46 in the second flexible diaphragm 40 form an annular orifice opening between the central pressure chamber 35 and the lower pressure chamber 45, whereby fluid may pass from the central pressure chamber into the lower pressure chamber.
  • the second flexible diaphragm 40 flexes in response to a pressure differential being present across this diaphragm due to a pressure difference existing between the pressure in the central pressure chamber 35 versus the pressure in the lower pressure chamber 45.
  • the hole 46 in the top of the thimble-like outward projection 44 on the second diaphragm 40 thereby translates axially relative to the tapered tip 82 in response to this pressure differential.
  • the flow area through the annular orifice opening formed between the rod 80 and the second diaphragm 40 varies.
  • the bleed valve assembly 10 includes a selectively positionable control valve 50 operatively associated with the bleed valve 20.
  • the control valve 50 is a three-position valve including a housing 51 having four ports 52, 54, 56 and 58, and a rotatable disc 53 disposed within the housing 51.
  • the rotatable disc 53 has internal fluid passages 55, 57 and 59 formed therein.
  • the control valve 50 is connected in pneumatic communication with the bleed valve 20, blood pressure cuff 100, and cuff inflation pump 104 via the aforementioned ports. As depicted in FIGS.
  • the blood pressure cuff 100 and the cuff inflation pump 104 are connected in pneumatic communication to the first port 52 of the control valve 50 via conduits 101 and 103. Additionally, the upper pressure chamber 25 of the bleed valve 20 is also connected in pneumatic communication to the first port 52 of the control valve 50 through conduit 105 via conduit 103.
  • the second port 54 of the control valve 50 is directly in pneumatic communication with ambient pressure either through conduit 109 or by simply via an opening directly through the housing 51 to the environment exterior of the control valve 50.
  • the third port 56 of the control valve 50 is connected in pneumatic communication to the lower pressure chamber 45 of the bleed valve 20 via conduit 111 and the fourth port 58 of the control valve 50 is connected in pneumatic communication to the central pressure chamber 35 of the bleed valve 20 via conduit 107.
  • Each of the conduits 101, 103, 105, 107, 109 and 111 maybe flexible tubes of the type conventionally used for blood pressure tubing.
  • the control valve 50 may be selectively positioned in one of three positions during the blood pressure measurement process. During inflation of the blood pressure cuff 100, the control valve 50 is positioned in a first position, as shown in FIG. 1, wherein blood pressure cuff 100, the cuff inflation pump, the upper chamber 25, the central chamber 35, and the lower chamber 45 are all connected together in pneumatic communication via the internal passages 57 and 59 of the control valve 50.
  • the rotatable disc 53 In this first position, the rotatable disc 53 is positioned such that the internal passages 57 and 59 thereof interconnect ports 52, 56 and 58 to form fluid flow passages therebetween as illustrated in FIG. 1.
  • the air pressure in each of the upper, central, and lower pressure chambers increases as the cuff pressure increases, thereby equalizing the pressures in first or upper pressure chamber 25, the second or central pressure chamber 35 and the third or lower pressure chamber 35 with the pressure in blood pressure cuff 100.
  • internal passage 55 In this first position, internal passage 55 is not in registration with any of the control valve ports and is therefore not functional.
  • the control valve 50 In the cuff deflation mode, the control valve 50 is positioned in a second position, as shown in FIG.
  • the control valve 50 is positioned in a third position, as shown in FIG. 3, for rapidly venting the blood pressure cuff 100 to ambient pressure and bypassing the bleed valve 20.
  • the disc 53 is rotated an additional 45 degrees clockwise from the second position to bring the internal passage 57 in registration with ports 52 and 54, thereby establishing a fluid flow passage connecting ports 52 and 54.
  • internal passage 59 is in registration with ports 52 and 58, thereby establishing a fluid flow passage connecting ports 58 and 54.
  • the blood pressure cuff 100 is connected directly via conduits 101, 103, and internal passage 57 with ambient pressure at port 54.
  • the second pressure chamber 35 is likewise connected directly with ambient pressure at port 54.
  • internal passage 55 is again not in registration with any of the control valve ports and is therefore not functional.
  • the operation of the bleed valve assembly 10 of the invention is described in connection with the process of taking a patient's blood pressure.
  • the operator inflates the blood pressure cuff 100 by pumping the hand pump 104, also referred to as a pressure bulb, as in conventional practice.
  • the operator Prior to initiating this inflation of the cuff 100, the operator places the control valve 50 of the bleed valve assembly 10 of the invention in its first position as shown in FIG. 1 by means of a hand dial (not shown) or other positioning device that operates to rotate the disc 53 amongst the three control valve positions selectable by the operator.
  • air supplied by pumping the hand pump 104 not only inflates the blood pressure cuff 100, but also simultaneously passes through conduits 103 and 105 to pressurize the upper pressure chamber 25 of the bleed valve 20; through conduit 103, control valve internal passage 57 and conduit 107 to pressurize the central pressure chamber 35 of the bleed valve 20; and through conduit 103, control valve internal passages 57 and 59, and conduit 111 to pressurize the lower pressure chamber 45.
  • each of the upper, central and lower pressure chambers are simultaneously pressurized to the same pressure, which is also the pressure to which the cuff 100 is pressurized.
  • the pressures on each side of the first (upper) flexible diaphragm 30 are equal, and as the effective pressure area below the diaphragm is slightly larger than that above the diaphragm, the top surface of central portion 34 of the first diaphragm 30 remains in contact against the O-ring 66, as is shown in Figure 4.
  • the first vent passage formed by the central bore 62 through the end fitting 60 is thereby closed, and no fluid escapes the upper pressure chamber 25 during the cuff inflation process.
  • the second diaphragm 40 Since the pressures on each side of the second (lower) flexible diaphragm 40 are equal, the second diaphragm 40 remains in its unflexed state. As a result, the relative positioning of the hole 46 in the central portion of the second diaphragm 40 with respect to the tapered tip 82 of the rod 80 remains at its preset position as is illustrated in FIG. 5. Therefore, the size of the annular orifice opening between the tapered tip 82 of the rod 80 and the surrounding hole 46 is unchanged. Because the pressures in the central and lower pressures are equal, no fluid flow occurs through the orifice opening.
  • the operator changes the positioning of the control valve 50 from its first position to its second position. This is accomplished by rotating a hand dial (not shown), and therewith the disc 53, clockwise 45 degrees. With the control valve 50 in this second position, ports 52 and 58 are now closed, thereby closing off the cuff 100, the upper pressure chamber 25, and the central pressure chamber 35.
  • a desired pressure level typically a pressure in excess of the patient's estimated systolic blood pressure
  • port 56 is now connected internally to port 54 via internal flow passage 55, thereby establishing direct pneumatic communication between the lower pressure chamber 45 and ambient pressure through conduit 111, internal passage 55, and port 54.
  • the pressure within the lower pressure chamber 45 drops to a level effectively at ambient pressure. Air vents from the central pressure chamber 35 through the orifice opening formed between the tapered tip 82 of the rod 80 and the surrounding hole 46, Figure 5, in the thimble-like portion 44 of the second diaphragm 40. The air then passes through the third pressure chamber 45, conduit 111, control valve internal passage 55, and out of port 54 to ambient pressure, which collectively form a second vent passage for the bleed valve 20.
  • the hole 46 in the central portion 44 of the second diaphragm 40 moves upwardly along the tapered tip 82 of the rod 80 while the second diaphragm 40 relaxes back toward its original unflexed state.
  • This upward movement of the hole 46 relative to the tapered tip 82 of rod 80 results in a continuous increase in the flow area of the orifice opening between the rod 80 and the surrounding hole 46 as the pressure within the central pressure chamber 35 decreases. Therefore, as the pressure within the central pressure chamber 35 decreases, the flow area through the orifice opening increases, thereby compensating for the decrease in the pressure within the central pressure chamber 35 so that the rate of pressure drop within the central pressure chamber 35 remains substantially constant.
  • the upper pressure chamber 25 is in pneumatic communication with the blood pressure cuff 100 and is pneumatically sealed from the central pressure chamber 35.
  • This pressure in the upper pressure chamber 35 is substantially equal to the cuff pressure.
  • a pressure differential builds across the first (upper) flexible diaphragm 30. This pressure differential acts to flex the first diaphragm 30 downwardly (i.e., toward the central pressure chamber 35) and out of contact with the O-ring 66 at the first vent passage formed by axial bore 62 that extends through the end fitting 60 in the upper end cap 26.
  • annular gap 67 opens therebetween. Air vents through this gap from the blood pressure cuff 100 through the upper pressure chamber 25 into and through conduit 62 directly to ambient pressure exteriorly of the bleed valve 20, whereby the blood pressure cuff begins to deflate.
  • the annular gap 67 continuously adjusts such that the pressures in pressure chambers 25 and 35 remain substantially equal. For example, should the pressure in pressure chamber 25 fall below that in pressure chamber 35, the diaphragm 30 moves upwards, thereby closing the annular gap and decreasing the flow of air to ambient pressure.
  • Air from the pressure chamber 35 bleeds through the variable area orifice formed between the rod 80 and the hole 46 in the top of the central portion of the second (lower) diaphragm 40. Therefore, since the bleed rate of pressure from the central pressure chamber 35 is substantially constant as hereinbefore discussed, the bleed rate of pressure from the blood pressure cuff 100 is also be substantially constant. Further, since the bleed rate of pressure from the blood pressure cuff 100, that is the cuff pressure decrease rate, is established by the bleed rate of pressure from the fixed volume central pressure chamber 35, the deflation rate of the cuff 100 is independent of the volume of the first pressure chamber 25 and of the associated blood pressure cuff 100. Thus, when the bleed valve assembly 10 of the invention is used, whether the blood pressure cuff 100 is a large adult cuff or a much smaller child's cuff, the cuff deflation rate is effectively the same.
  • the magnitude of the cuff deflation rate is set by the initial axial placement of the tapered tip 82 of the rod 80 relative to the second (lower) flexible diaphragm 40 in its unflexed state.
  • the tapered tip 82 of the rod 80 is placed nearly at the top edge of the hole 46 in the central portion of the second flexible diaphragm 40. In this position, a particular magnitude for the bleed rate of pressure from the lower pressure chamber 45 is established as the diaphragm 40 moves upwardly after the start of the cuff deflation mode.
  • the tip of the tapered tip 82 of the rod 80 may be initially set more axially downward, i.e. lower in comparison to the embodiment in FIG. 5, so that the tip does not extend as far into the hole 46.
  • the tapered tip 82 of the rod 80 may be initially set more axially upward, i.e. higher in comparison to the embodiment in FIG. 5, so that the tapered tip 82 of the rod 80 extends through and beyond the hole 46.
  • the initial position of the rod 80 relative to the unflexed second flexible diaphragm may be easily adjusted to establish a cuff pressure decrease rate in the generally desired range of 2-3 millimeters Hg per second.
  • the behavior of the pressure bleed rate during deflation is determined by the shape of the tapered tip 82.
  • This shape may be conical, axisymmetric but not conical, or non-axisymmetric.
  • the shape can be chosen to achieve a linear/constant/deflation rate or to achieve a rate that increases or decreases as the pressure falls. For example, a more gradual taper produces a rate that decreases as the pressure falls. A more abrupt taper produces a rate that increases as the pressure falls.
  • the operator may concentrate on accurately detecting the systolic and diastolic blood pressure measurements of the patient. Once the diastolic blood pressure measurement has been detected, the operator may reset the control valve 50 to rapidly further deflate the cuff 100 to relieve the pressure exerted by the cuff 100 on the patient's limb, thereby enhancing patient comfort.
  • the operator resets the control valve 50 to its third position by rotating the disc 53, for example by means of a hand dial (not shown), a further 45 degrees to align the interior passage 57 in registration with the ports 52 and 54 and to simultaneously align the interior passage 59 in registration with the ports 52 and 58, as depicted in FIG. 3.
  • the interior passage 55 is not in registration with any of the ports of the control valve and is not functional.
  • the blood pressure cuff 100 is now in direct pneumatic communication with ambient pressure via conduits 101 and 103, and via the control valve internal passage 57.
  • Internal passage 57 provides a fluid flow path between the ports 52 and 54.
  • a temporary increase could be desired after the systolic pressure has been noted, but while the decreasing cuff pressure is still well above the expected diastolic pressure.
  • This temporary increase could be provided via means for momentarily moving the control valve between the second and third positions.
  • This temporary increase could also be provided via means for momentarily moving the tapered rod axially downward from its normal operative position.
  • the bleed valve assembly of the invention has been described herein an exemplary embodiment particularly advantageous for use in application to blood pressure measurement manually. However, those skilled in the art will recognize that the bleed valve assembly of the invention is also suitable for use in connection with an electronic blood measurement apparatus. In a preferred embodiment of such an apparatus, the subject valve and a hand pump may be employed.
  • the electronic apparatus would contain an electronic module having a pressure transducer, an oscillometric data processor, and a display. Such an embodiment could be made low cost by avoiding use of a high cost electrical pump and electrically modulated bleed valve. Also, power usage could be low via use of the subject non-electric valve, manual pump, and a low power electronic module. Further, it should be understood that the bleed valve assembly 10 of the invention may also be employed in connection with venting any pressure reservoir wherein it is desired to vent pressure from the reservoir at a substantially constant rate without manual adjustment of a bleed valve.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Vascular Medicine (AREA)
  • Cardiology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Physiology (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Ophthalmology & Optometry (AREA)
  • Physics & Mathematics (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

L'invention concerne un ensemble de soupape de purge de la pression sanguine servant à ventiler de l'air provenant d'une manchette à pression à un taux de diminution de pression relativement constant en dépit de la taille de la manchette. Cet ensemble comprend une soupape de purge à plusieurs chambres et une soupape de commande à plusieurs positions associées fonctionnellement. Une première chambre d'extrémité est reliée en communication pneumatique avec la manchette, est fermée pneumatiquement au moyen d'un premier diaphragme flexible et n'est pas en contact avec une seconde chambre centrale. Une troisième chambre d'extrémité est séparée de la chambre centrale par un second diaphragme flexible. Une ouverture de zone à écoulement variable à travers le second diaphragme fournit une voie d'écoulement afin de ventiler de l'air de manière régulée provenant de la seconde chambre à une pression ambiante, lorsque la soupape de commande est positionnée sélectivement pour relier la troisième chambre en communication pneumatique avec la pression ambiante. De l'air est ventilé de la manchette à travers la première chambre dans une réponse régulée au différentiel de pression entre les première et seconde chambres agissant sur le premier diaphragme flexible.
PCT/US2006/035302 2005-09-13 2006-09-12 Ensemble de soupape de purge de la pression sanguine Ceased WO2007033074A2 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2008531217A JP2009507610A (ja) 2005-09-13 2006-09-12 血圧ブリードバルブアセンブリー
EP06803325A EP1931244A2 (fr) 2005-09-13 2006-09-12 Ensemble de soupape de purge de la pression sanguine

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US11/225,744 US20070060825A1 (en) 2005-09-13 2005-09-13 Self-compensating blood pressure bleed valve
US11/225,744 2005-09-13
US11/507,238 2006-08-21
US11/507,238 US8066645B2 (en) 2005-09-13 2006-08-21 Blood pressure bleed valve assembly

Publications (2)

Publication Number Publication Date
WO2007033074A2 true WO2007033074A2 (fr) 2007-03-22
WO2007033074A3 WO2007033074A3 (fr) 2007-05-24

Family

ID=37865480

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2006/035302 Ceased WO2007033074A2 (fr) 2005-09-13 2006-09-12 Ensemble de soupape de purge de la pression sanguine

Country Status (2)

Country Link
EP (1) EP1931244A2 (fr)
WO (1) WO2007033074A2 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2387366C2 (ru) * 2007-09-11 2010-04-27 Михаил Александрович Кожевников Устройство для регулирования и контроля давления в манжете воздуховода

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4587974A (en) * 1984-11-13 1986-05-13 Norse Instruments Linear pressurizing and depressurizing device
JP2507031Y2 (ja) * 1990-07-03 1996-08-14 シチズン時計株式会社 血圧計用定速排気調節装置

Also Published As

Publication number Publication date
WO2007033074A3 (fr) 2007-05-24
EP1931244A2 (fr) 2008-06-18

Similar Documents

Publication Publication Date Title
US8066645B2 (en) Blood pressure bleed valve assembly
US5220925A (en) Electronic sphygmomanometer
EP0727961B1 (fr) Systeme de surveillance non invasif et continu de la pression sanguine
US2753863A (en) Sphygmomanometers
US5090417A (en) Medical diagnostic apparatus
US4178918A (en) Automatic blood pressure measuring and recording system
US5240008A (en) Inflation control apparatus for an automatic blood pressure gauge
EP3681387B1 (fr) Appareil de gonflage pour un moniteur de pression sanguine non invasif basé sur le gonflage et son procédé de fonctionnement
US7018337B2 (en) Method and apparatus for automatic non-invasive blood pressure monitoring
US5464019A (en) Airflow control manifold for automatic blood pressure monitoring device
EP0576328B1 (fr) Sphygmomanomètre automatique
US8652056B2 (en) Deflation control valve
US5772596A (en) Osteoporosis apparatus
WO2007033074A2 (fr) Ensemble de soupape de purge de la pression sanguine
US4768518A (en) Pressure control system and apparatus for the cuff of an automatic non-invasive blood pressure meter
US6394959B1 (en) Continuous blood-pressure monitor apparatus
GB1588954A (en) Blood pressure measuring device
JPH0239248B2 (fr)
JPS5828567Y2 (ja) 血圧計用排気装置
WO2013159410A1 (fr) Jauge de pression artérielle avec microphone à système micro-électro-mécanique (mems)
CN211962029U (zh) 基于血压测量的智能泄压系统
GB2211616A (en) Medical diagnostic apparatus
KR20140145483A (ko) 밸브 모듈을 구비하는 혈압 측정 장치
JP2002062208A (ja) 静電容量型圧力センサ
GB2438371A (en) Deflation valve

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
ENP Entry into the national phase

Ref document number: 2008531217

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2006803325

Country of ref document: EP