WO2010061173A1

WO2010061173A1 - Medical gas administration device and kit

Info

Publication number: WO2010061173A1
Application number: PCT/GB2009/002719
Authority: WO
Inventors: Paul Wadham
Original assignee: The Boc Group Limited
Priority date: 2008-11-25
Filing date: 2009-11-20
Publication date: 2010-06-03
Also published as: GB0821512D0

Abstract

A medical gas administration device comprising a hollow body (2, 4) which a) houses a positively-seating inhalation valve (14), a positively-seating exhalation valve (30) and a positively-seating anti-asphyxiation valve (40); b) has a first port (6) on the inlet side of the inhalation valve connectable to a breathing bag (8); c) has a second port (22) also on the inlet side of the inhalation valve connectable to a source of medical gas; d) has a third port (24) on the outlet side of the inhalation valve connectable to an interface device (60) with the patient; e) has a fourth port (28) on the outlet side of the inhalation valve communicating with the external atmosphere, the fourth port serving as an outlet from the exhalation valve; and f) has a fifth port (38) on the outlet side of the inhalation valve communicating with the external atmosphere, the fifth port serving as an inlet to the anti-asphyxiation valve.

Description

MEDICAL GAS ADMINISTRATION DEVICE AND KIT

This invention relates to a medical gas administration device and to a medical kit including the medical gas administration device.

Medical gases are playing an increasingly important role in medicine and therapy. It is well known to administer oxygen from a pressurised gas cylinder to a patient in order to aid the patient's breathing. It is also known to administer a gaseous mixture of helium and oxygen to a patient in order to alleviate symptoms associated with asthma or COPD. Other well known medical gas mixtures include those of oxygen and nitrous oxide which have an anaesthetic or analgesic effect. In order to administer a medical gas mixture, the source of the mixture is connected to a suitable device such as a face mask which fits over the patient's nose and mouth. The face mask is provided with inhalation and exhalation valves. The face masks are made in a number of different sizes according to the patient's age and size. These requirements add complexity to the manufacture of the face mask.

Medical gas mixtures conform to strict compositional requirements. Typically, however, during administration to a spontaneously breathing patient, the medical gas mixture is diluted with air. For example, air leaks through the exhalation valve, in particular. Should the inhalation valve become stuck in the closed position, the patient will be able to breathe in air through the exhalation valve. Another source of the air that dilutes the medical gas mixture is through the gap between the face mask and the patient's face. This gap may be quite large if the mask is a poorly fitting one. It can be appreciated that the amount of dilution can be large and unpredictable. As a result, there may be an adverse effect on the efficacy of the medical gas mixture.

According to the present invention there is provided a medical gas administration device comprising a hollow body which: a) houses a positively-seating inhalation valve, a positively-seating exhalation valve and a positively-seating anti-asphyxiation valve; b) has a first port on the inlet side of the inhalation valve connectable to a breathing bag; c) has a second port also on the inlet side of the inhalation valve connectable to a source of medical gas; d) has a third port on the outlet side of the inhalation valve connectable to an interface device with the patient; e) has a fourth port on the outlet side of the inhalation valve communicating with the external atmosphere, the fourth port serving as an outlet from the exhalation valve; and f) has a fifth port on the outlet side of the inhalation valve communicating with the external atmosphere, the fifth port serving as an inlet to the anti-asphyxiation valve.

The invention also provides a medical kit including the medical gas administration device as defined in the paragraph immediately herein above.

The medical kit according to the invention typically additionally comprises a breathing bag and an interface device with the patient such as a face mask. By having the face mask as a separate item, manufacture is simplified. Typically, in a medical kit according to the invention the face mask may be selected from one of a number of different sizes whereas the administration device according to the present invention may be of a standard size. It is envisaged that two standard administration devices according to the invention may be manufactured, one for adult patients and the other for paediatric ones.

A further advantage of the medical gas administration device according to the invention is that by employing a positively-seeking anti-asphyxiation valve and a positively-seating exhalation valve, dilution of the medical gas (which term, as used herein, encompasses mixtures of medical gases) with air can be kept down. Any leak of air to a spontaneous by breathing patient may be further kept down if the face mask or other interface device has a cushioned cuff, thereby enabling it to be held tightly against the face with minimal discomfort to the patient.

Preferred features of the medical gas administration device according to the invention comprise the following:

The hollow body is typically generally tubular and lightweight. It is typically disposable, preferably comprises first and second engaging body members. The first body member is preferably tubular and open ended. One end defines the first part and the other end enages the second body member, the second port being formed in the first body member intermediate the open ends. The use of a breathing bag makes possible instantaneous rates of inhalation greater than the rate at which the medical gas is supplied to the administration device according to the invention. The second body member preferably has an elbow, at an angle of up to 20° to the horizontal.

The first body member preferably houses the inhalation valve.

The exhalation valve is preferably an umbrella valve, that is a valve which has a valve member the shape of the canopy of an open umbrella. The resilience of the valve member provides a positive seating pressure. This pressure is typically in the order of a fraction of a mbar.

The anti-asphyxiation valve is preferably a spring-loaded piston valve, the spring-loading providing the positive seating pressure. The bias of the spring, typically a compression spring, is chosen such that the valve will open if subjected to sufficient suction on its outlet side. The inhalation valve is preferably an umbrella valve similar to the exhalation valve. The inhalation valve is preferably positively seating.

The second body member is preferably open-ended and elbow-shaped with one end engaging the first body member and the other end terminating in the third port.

The third port preferably receives and fixedly engages an adapter for connection to a patient interface device. A range of different sized adapters may be used to enable a single administration device to be connected to a range of different sized interface devices (face masks).

The first and second body members are preferably made of clear, transparent plastics material. They are preferably made as injection mouldings.

A medical kit according to the invention preferably includes in addition to a medical gas administration device according to the invention, an interface device with the patient such as a facemask, a breathing bag, and instructions for use. The kit may be appropriately packaged.

A medical gas administration according to the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a sectional side elevation of the device;

Figure 2 is a further side elevation of the device;

Figure 3 is schematic exploded perspective view of the device shown in Figures 1 and 2 and; Figure 4 is a perspective view of an alternative medical gas administration device to the one shown in Figures 1 - 3.

The drawings are not to scale.

Referring to Figures 1 - 3 of the drawings, a disposable medical gas administration device is generally tubular and lightweight and comprises a first or lower body member 2 which is permanently engaged to an upper or second body member 4 in the form of an elbow. The body members 2 and

4 are both hollow and open-ended. They are typically made of clear plastics material, for example by injection moulding.

The medical gas device is preferably used in the orientation shown in Figures 1 and 2, that is with the first body member 2 vertical. The angle of the elbow with which the second body member 4 is formed is chosen so that a face mask attached to the second body member 4, as will be described below, is at a natural angle for comfortable use by a spontaneously breathing patient. This angle is typically in the range of 10 to 20° to the horizontal.

The first body member 2 has a first port 6 at its lower end (as shown). With reference to Figure 3, this port 6 is connectable to a breathing bag 8 which may be made of PVC or similar plastics material. The breathing bag is preferably translucent. Its capacity will depend on whether the patient is a paediatric patient or an adult patient. The capacity of the breathing bag for paediatric patient may be in the order of one litre and for an adult patient in the order of two litres. Again, with reference to Figure 3, the mouth of the breathing bag is fastened or glued to the connector 10 which is integral with the bag 8 and which is adapted to mate with the first port 6 of the first body member 2. In Figure 3, there is shown a length of tape 12 so as to fasten the breathing bag to the first port. The first port 6 and the connector 10 may, alternatively, be provided with appropriate coupling members (not shown).

Referring now to Figure 1 , the first body member 2 houses an inhalation valve 14. The inhalation valve 14 is in the form of an umbrella valve. The inhalation valve 14 has a valve seat 16 engaging the first body member 2 and an umbrella member 18 whose curvature and material of construction is such that the periphery of the umbrella member 18 positively engages the valve seat 16.

The first body member has an integral side nozzle 20 which defines a second port 22. The second port 22 may be connected via a length of flexible tubing (not shown) to a source of medical gas (not shown) (for example a cylinder containing a mixture of helium and oxygen under pressure in defined proportions).

With reference to Figures 1 and 2, in particular, the second body member 4 terminates in a third port 24 which is able to be connected to a face mask (not shown) or other suitable interface device with a patient. Preferably, the connection is made through an adapter 26 which is received in the third port makes a frictional engagement therewith. It can be seen from Figure 1 , in particular, that the third port 24 is on the downstream side of the inhalation valve 14.

The second body member 4 is formed with a fourth port 28 in its side. The fourth port 28 has an exhalation valve 30 mounted therein. The exhalation valve 30 is an umbrella valve similar to the inhalation valve 14. The inhalation valve 30 has a valve seat 32 and an umbrella member 34 whose curvature and material of construction is such that its periphery makes a positive valve-closing engagement with the valve seat 32. The umbrella member 34 is provided with a valve cover 36 to protect it during normal use. As can be seen from Figure 1 , the inlet side the exhalation valve 30 is on the outlet side of inhalation valve 14. The outlet side of the exhalation valve communicates with the external atmosphere through a gap defined between the cover 36 and the umbrella member 34. In use, when a patient exhales, the pressure of the exhaled gas will overcome the resilience of the umbrella member 34 and cause the exhalation valve 30 to open, thus allowing the exhaled gases to be vented to the atmosphere. Accordingly, there will be minimal contamination of inhaled gases with the exhaled gases.

With reference to Figure 1 , opposite the fourth port, there is formed in the second body member 4, a fifth port 38 which is associated with an anti- asphyxiation valve 40. The anti-asphyxiation valve 40 comprises a piston member 42 of plastics material which is integral with a shaft 44 having an end 46 which is reciprocal within a guide member 48. The piston member 42 seats against a region of the interior surface of the body member 4 circumscribing the fifth port 38 when the anti-asphyxiation valve 40 is in its closed position. The piston member 42 is biased into this closed position by means of a compression spring 56, one end of which end seats against the guide member 48 and the other end of which bears on the piston member 42. The bias of the compression spring is carefully selected according to whether the intended patient is a child or an adult. The anti- asphyxiation valve opens only in the event of the exhalation valve 30 becoming stuck in the closed position. In this event, the natural suction created by the patient's breathing will overcome the bias of the compression spring 56 and cause the anti-asphyxiation valve 40 to open to the external atmosphere, thereby allowing the patient to breathe natural air. The bias of the compression spring 56 is thus such that the anti- asphyxiation valve opens at a minimum pressure differential across the piston member 42 slightly greater than the corresponding minimum pressure differential at which the exhalation valve 30 opens. Thus, in normal operation, the anti-asphyxiation valve 40 remains closed. As is best shown in Figure 2, the anti-asphyxiation valve 40 has a guard member 50 engaged within the fifth port 38 for protecting the anti- asphyxiation valve 40 from the kind of buffeting that might occur in normal use. The guard member 50 typically has a central hub 52 and a plurality of radial spokes 54. The hub 52 also acts as a guide for the shaft 44. The spokes 54 are sufficiently spaced apart not to provide any significant obstruction to the flow of air from the external atmosphere through the anti-asphyxiation valve 40 in the event of its opening.

Reference is made to Figure 4 which shows a device essentially similar to that shown in Figures 1 - 3. Parts that are essentially the same in Figure 4 as corresponding parts in the device shown in Figures 1 - 3 are indicated by the same reference numerals are as used in those Figures and shall not be described again.

Figure 4 does, however illustrate a face mask 60 for use with the device 2. The face mask 60 is typically made of clear transparent plastics material. Its outer periphery is provided with a cuff 62 which forms a cushion between the patient's face and the rest of the mask. The cuff 62 is preferably formed of a relatively soft elastomeric material. In use, the patient may simply hold the face mask 60 to his or her face. The configuration of the cuff 62 is such that it keeps down in leakage of air between the mask 60 and the patient's face. Typically, the face mask fits over the patient's nose and mouth.

By keeping down the leakage of air between the face mask and the patient, dilution of the medical gas which is administered through the administration device according to the invention is kept down. The positive seating nature of the exhalation valve 30 also helps to keep down in leakage of air because it prevents any air being drawn in to the device during the aspiratory phase of the patient's breathing. As an alternative to the patient's manually holding the face mask, the medical gas administration device according to the invention may be provided with a hook ring 70, as shown in Figure 4 to receive a length or lengths of ribbon or the like that can be tied behind the patient's neck so as to hold the face mask in place.

With the exception of the compression spring 50 of the anti-asphyxiation valve 40, all the parts of the medical gas administration device according to the invention whether as shown in Figures 1 - 3 or in Figure 4 of the drawings or not, may be made of suitable plastics and elastomeric material. The main body members 2 and 4 may, for example, be made of a polycarbonate. The umbrella members of the umbrella valves may be made of a silicone rubber which exhibits both resilience and stiffness. The first body member 2 may engage the second body member 4 by means of engagement clips 17.

A medical gas administration device, for example, as shown in Figures 1 - 3 may be incorporated into a packaged kit including in addition to the device, a face mask and a breathing bag, a length of tubing to enable the second port 22 to be connected to a source of medical gas and a set of instructions for use.

Claims

1. A medical gas administration device comprising a hollow body which

a) houses a positively-seating inhalation valve, a positively-seating exhalation valve and a positively-seating anti-asphyxiation valve; b) has a first port on the inlet side of the inhalation valve connectable to a breathing bag; c) has a second port also on the inlet side of the inhalation valve connectable to a source of medical gas; d) has a third port on the outlet side of the inhalation valve connectable to an interface device with the patient; e) has a fourth port on the outlet side of the inhalation valve communicating with the external atmosphere, the fourth port serving as an outlet from the exhalation valve; and f) has a fifth port on the outlet side of the inhalation valve communicating with the external atmosphere, the fifth port serving as an inlet to the anti-asphyxiation valve.

2. A medical gas administration device according to claim 1 , wherein the hollow body comprises first and second engaging body members.

3. A medical gas administration device according to claim 2, wherein the first body member is tubular and open-ended, one end defining the first port, and the other end engaging the second body member.

4. A medical gas administration device according to claim 2 or claim 3, wherein the first body member houses the inhalation valve.

5. A medical gas administration device according to claim 4, wherein the second part is provided at the side of the first body member upstream of the inhalation valve.

6. A medical gas administration device according to any one of claims 2 to 5, wherein the second body member has an elbow.

7. A medical gas administration device according to any one of claims 2 to 6, wherein the second body member houses the exhalation valve and the anti-asphyxiation valve.

8. A medical gas administration device according to any one of the preceding claims, wherein the exhalation valve is an umbrella valve.

9. A medical gas administration device according to claim 8, wherein the resilience of the valve member of the umbrella valve provides the positive seating pressure.

10. A medical gas administration device according to any one of the preceding claims, wherein the anti-asphyxiation valve is a spring- loaded piston valve, the spring loading providing the positive seating pressure.

1 1. A medical gas administration device according to any one of the preceding claims, wherein the inhalation valve is an umbrella valve.

12. A medical gas administration according to any one of the preceding claims, wherein the third port receives and positively engages an adaptor for connection to a patient interface device.

13. A medical gas administration device according to any one of the preceding claims that is disposable.

14. A medical including a medical gas administration device according to any one of the preceding claims.

15. A medical kit according to claim 14, additionally including a patient interface device, a breather bag and instructions for use.

16. A medical kit according to claim 15, wherein the patient interface device is a face mask.

17. A medical kit according to claim 16, wherein the face mask has a cush at its outer periphery to facilitate close fitting to a patient's face.