GB2430380A

GB2430380A - Ventilator assembly with valve and filter

Info

Publication number: GB2430380A
Application number: GB0618720A
Authority: GB
Inventors: Jonathan Kevin Ben; Paul James Leslie Bennett; Robert James Burchell
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 2005-09-27
Filing date: 2006-09-22
Publication date: 2007-03-28
Also published as: GB0618720D0; GB0519627D0

Abstract

A gas-powered ventilator has a patient valve assembly 2 with a housing 20 containing a duck-bill valve element 60 arranged to allow gas to flow from the ventilator 1 to the patient during inhalation. The valve element 60 closes during exhalation, diverting the exhaled gas to exhaust ports 30 in the housing 20 and substantially preventing exhaled gas flowing back to the ventilator. The valve housing 20 also contains a filter 50 between the valve element 60 and the patient outlet 5 so that all gas flowing to and from the patient passes through the filter and the ventilator is thereby protected from contamination from any gas that might seep back through the valve element. The valve assembly 2 is removable from the ventilator 1 as a single unit so that it can be disposed of and replaced between patients.

Description

1 2430380

VENTILATOR ASSEMBLIES AND VALVES

This invention relates to ventilator assemblies and to valves.

Ventilators or resuscitators are used to supply a breathing gas such as air, oxygen or a mixture of air and oxygen to a patient who needs assistance with breathing. The ventilator may be of the manual kind where a resilient bag is squeezed by hand to provide gas pressure to the patient, such ventilators are sold, for example by Smiths Medical under the Portex I Response trade mark. Alternatively, the ventilator may be of the gas-powered kind such as sold by Smiths Medical under the Pneupac trade mark. The outlet of the ventilator is coupled to a face mask or tracheal tube by which the gas is supplied to the patient. Such ventilators are provided with a patient valve adjacent the outlet, which operates to allow gas to flow out of the ventilator to the patient but prevents gas exhaled by the patient flowing back into the main part of the ventilator and instead diverts it to an exhalation port open to atmosphere.

The patient valve is usually removed and replaced, or is sterilized, between patients in order to prevent cross-infection. Although the patient valve operates to prevent the major part of the exhaled gas entering the ventilator, it may not entirely prevent this. It is recommended, therefore, that a filter (such as that the electrostatic filter sold by Smiths Medical under the Portex trade mark, Part No 2862) be connected between the patient valve and the face mask or tracheal tube so that contamination cannot enter the patient valve. Connecting the filter, however, adds a further step to use of the ventilator and thereby complicates its use and increases the delay before ventilation is administered. Also, the inclusion of the filter increases the bulk of the apparatus and the separation between the ventilator and the patient, which may make it more difficult to hold.

It is an object of the present invention to provide an alternative valve and ventilator.

According to one aspect of the present invention there is provided an assembly of a gas-powered ventilator and a patient valve assembly, the valve assembly having a housing provided with a first connection at one end for connection with a face mask or tracheal tube and a second connection at its opposite end removably connected with an outlet of the ventilator, the valve assembly further including valve means located within the housing and operable to allow gas to flow from the ventilator to the patient and to divert gas exhaled by the patient to an exhalation port, and gas-treatment means located within the housing to prevent contamination from exhaled gas entering the ventilator.

The gas-treatment means is preferably arranged such that all gas exhaled by the patient passes through the gas-treatment means and the gastreatment means may be located between the valve means and the one end. The valve means preferably includes a flexible, displaceable valve element and may be provided by a duck-bill valve. The gas-treatment means is preferably arranged to prevent passage of contaminants and may be a filter. The valve assembly preferably includes a flap valve over the exhalation port.

According to another aspect of the present invention there is provided a valve assembly for a ventilator assembly according to the above one aspect of the present invention.

A ventilator including a valve assembly according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a simplified side view of the ventilator with a patient valve assembly connected to a face mask; Figure 2 is a cross-sectional side elevation view of a first example of the patient valve assembly connected with a ventilation outlet port; Figure 3 is a cross-sectional side elevation view of a second alternative example of the patient valve assembly; Figure 4 is a cross-sectional side elevation view of a third alternative example of the patient valve assembly; and Figure 5 is a cross-sectional side elevation view of a fourth alternative example of the patient valve assembly.

With reference first to Figures 1 and 2, there is shown a conventional ventilator 1 with a patient valve assembly 2 connected at its inlet end 3 with the ventilator outlet port 4 and at its outlet end 5 with a female tapered fitting 6 on a face mask 7.

The ventilator 1 is entirely conventional and, as shown, is a gas-powered ventilator as sold by Smiths Medical under the "PneuPac VRI" trade mark. It is not necessary for an

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understanding of the present invention to describe the operation of the ventilator in any detail but further information about its operation and structure can be seen in W005/023349, EP 1660163 and W006/075 129. The ventilator 1 receives a supply of pressurized oxygen at its inlet 8 and provides a controllable, cyclical flow of oxygen or an air/oxygen mixture at its outlet 4. The outlet takes the form of a tubular port 4, which is enlarged radially at its lower end and is formed with an internal screw thread 9, although it will be appreciated that any other form of fitting could be used, such as a bayonet fitting. A stop plate 25 with apertures 26 extends internally, laterally across the ventilator outlet port 4.

The patient valve assembly 2 is a separate and disposable item, which is removable from the ventilator 1. The valve assembly 2 has an outer plastics housing 20 of tubular shape formed by upper and lower mouldings 22 and 23. The inlet end 3 of the valve 2 is formed by the upper end of the upper moulding 22 and has an external screw thread 24 shaped to engage the screw thread 9 on the ventilator outlet port 4. The upper moulding 22 has a flange 27 with a central aperture 28 and an outer, cylindrical waIl 29 on which the screw thread 24 is formed. The flange 27 has several exhalation ports 30 formed through it and distributed around the moulding. The aperture 28 of the upper moulding 22 receives the lower moulding 23, which is tubular in shape and is rotatable about its axis relative to the upper moulding 22. The upper end of the lower moulding 23 has an outwardly-extending flange 31, which locates on the upper, internal face of the flange 27 of the upper moulding 22, around the aperture 28. The lower moulding 23 is retained with the upper moulding 22 by means of a snap ring 40, which locates in a groove 41 around the lower moulding. The ring 40 has an angled step 42 around its upper face and this serves to trap a flexible washer 43 between the ring and the lower face of the upper moulding 22. The washer 43 acts as a flap valve over the exhalation ports 30 and provides some barrier to contamination. The lower end of the lower moulding 23 is formed with a taper on its outer surface to enable it to make a sealing fit with the inside of a female tapered connector 6 on the face mask 7 or on a tracheal tube.

The lower moulding 23 supports a gas-treatment element 50 internally. The gas- treatment element 50 is of solid cylindrical configuration, and is bonded around its external surface to the inside of the moulding 23 so that all gas flow along the moulding is confined to the body of the element 50 and none flows between the outside of the element and the moulding. The gas- treatment element 50 preferably takes the form of a filter effective to prevent contamination passing through it. In this respect the filter could be a HEPA bacterial and viral filter. Alternatively, the element 50 could prevent the passage of contaminants in other ways and could, for example, take the form of a substance that renders bacteria and viruses innocuous, such as a bactericidal and viricidal substance. The element could have heat and moisture exchange characteristics so that heat and moisture in gas exhaled by the patient is transferred to the element and this, in turn, is transferred to the gas supplied to the patient from the ventilator.

The patient valve assembly 2 is completed by a displaceable, flexible valve element trapped around its outer edge 61 between the upper moulding 22 and the lower end of the outlet port 4. The valve element 60 can be of conventional form, being moulded from a resilient, elastomeric material, such as silicone, and being of circular shape. In its centre, the valve element 60 has a duck-bill formation 62 with two lips 63 angled downwardly together towards the outlet end 5 and abutting one another at an openable slit 64. The duck-bill formation 62 is arranged such that the lips 63 separate slightly to allow gas to flow through the slit 64 when gas pressure above the valve element 60 is greater than that below. The duck-bill formation 62 closes to prevent gas flow through the slit 64 in the opposite direction when pressure is in the opposite sense. The duckbill formation 62 is surrounded by a flat, annular sealing portion 65 the lower surface of which extends above the upper end 13 of the lower moulding 23. The outer edge 61 of the valve element 60 is thickened so that it can be trapped securely between the upper edge of the outer waIl 29 of the upper moulding 22 and a lower surface of the outlet port 4. The valve element 60 is shaped with a V-shape bellows formation 66 between the outer edge 61 and the sealing portion 65 to allow the central part of the valve element to move up and down relative to the outer edge. Upward displacement of the valve element 60 is limited by engagement with the underside of the stop plate 25. The valve element 60 is arranged such that positive pressure applied by the ventilator 1 pushes the valve element down so that the sealing portion 65 seals against the upper edge 13 of the lower moulding 23 and so that the duck-bill valve 62 opens to allow gas to flow through it to the patient It will be appreciated that no gas will escape through the exhalation ports 30 because the seal between the sealing portion 65 and the upper edge 13 of the lower moulding 23 isolates the ports from the outlet end 5. When gas supply from the ventilator 1 ceases and the patient exhales, pressure below the valve element 60 rises so that the duck-bill valve 62 closes and the sealing portion 65 is lifted up off the edge 13 of the lower moulding 23, thereby allowing gas to flow out of the exhalation ports 30. It will be appreciated that other forms of valve could be used to serve the same function, which could be provided by several separate items.

It can be seen that all the exhaled gas from the patient must flow through the filter 50.

In this way, there is no risk of any contamination seeping through the duck-bill valve 62 into the interior of the ventilator I, thereby ensuring that, once the patient valve is replaced, the ventilator can be used on the next patient without any risk of cross-contamination. The location of the filter 50 also ensures that all gas flowing out of the exhalation ports 30 must first pass through the filter. This ensure that the caregiver using the ventilator I is also protected from any contamination from the patient. The arrangement is compact and requires no additional steps to assemble, avoiding multiple interconnections and potential sites for leakage and inadvertent separation. The arrangement also avoids the risk of the filter being omitted, which could cause cross- contamination or require expensive sterilization of the ventilator itself. The cost of providing a filter integral with the patient valve can be less than the cost of providing two separate components.

Instead of the cylindrical filter shown in Figure 2, the filter, or other gas-treatment element, could be of a cup shape, as shown by the element 50' in Figure 3, where the element is located between the valve element 60' and the patient, and where the duck-bill valve 62' projects within an upper, open end of the element.

Alternatively, the gas-treatment element 50" could be of a flat, disc shape and be located in an enlarged portion of the moulding 23", again on the patient side of the valve element 60", as shown in Figure 4. A third possible alternative configuration is shown in Figure 5 where the gastreatment element is a flat, disc shape filter 50" and is located above the valve element 60", in the ventilator outlet port 4", which is regarded as a part of the valve assembly and which would be removable with the rest of the valve assembly. Such an arrangement would have the disadvantage that exhaled gas would not be filtered before flowing to the exhaust ports. It would, however, have the advantage that the filter 50" would be exposed to less contaminated gas (because of the interposition of the valve element) so it could have a longer life. It would also not present any impediment to exhaled gas flow, which might be advantageous in some circumstances, such as when being used on young children or babies. For additional security, two filters could be included, one on the outlet side of the valve element and the other on the inlet side of the valve element.

Before use, the patient valve could be enclosed in a plastic break-off cover to protect it from contamination. The cover could completely enclose the valve or it could just cover those parts exposed to gas flow, such as the inlet, outlet and exhaust ports. The cover could include a legend to indicate the single-use nature of the product. In this respect, the cover could be arranged such that, once opened, it revealed a legend "Used Valve" or the like so that, if a used valve were not disposed of immediately it would be apparent to a user that it had been used.

Claims

1. An assembly of a gas-powered ventilator and a patient valve assembly, the valve assembly having a housing provided with a first connection at one end for connection wth a face mask or tracheal tube and a second connection at its opposite end removably connected with an outlet of the ventilator, wherein the valve assembly further includes valve means located within the housing and operable to allow gas to flow from the ventilator to the patient and to divert gas exhaled by the patient to an exhalation port, and gas-treatment means located within the housing to prevent contamination from exhaled gas entering the ventilator.

2. An assembly according to Claim 1, wherein the gas-treatment means is arranged such that all gas exhaled by the patient passes through the gastreatment means.

3. An assembly according to Claim I or 2, wherein the gas-treatment means is located between the valve means and the one end.

4. An assembly according to any one of the preceding claims, wherein the valve means includes a flexible, displaceable valve element.

5. An assembly according to Claim 4, wherein the valve element is provided by a duck-bill valve.

6. An assembly according to any one of the preceding claims, wherein the gas-treatment means is arranged to prevent passage of contaminants.

7. An assembly according to Claim 6, wherein the gas-treatment means is a filter.

8. An assembly according to any one of the preceding claims, wherein the valve assembly includes a flap valve over the exhalation port.

9. A ventilator assembly substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

10. A ventilator assembly substantially as bereinbefore described with reference to Figures 1 and 2 as modified by Figure 3 of the accompanying drawings.

11. A ventilator assembly substantially as hereinbefore described with reference to Figures 1 and 2 as modified by Figure 4 of the accompanying drawings.

12. A ventilator assembly substantially as hereinbefore described with reference to Figures 1 and 2 as modified by Figure 5 of the accompanying drawings.

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13. A valve assembly for a ventilator assembly according to any one of the preceding claims.

14. A valve assembly substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

15. A valve assembly substantially as hereinbefore described with reference to Figures 1 and 2 as modified by Figure 3 of the accompanying drawings.

16. A valve assembly substantially as hereinbefore described with reference to Figures 1 and 2 as modified by Figure 4 of the accompanying drawings.

17. A valve assembly substantially as hereinbefore described with reference to Figures 1 and 2 as modified by Figure 5 of the accompanying drawings.

18. Any novel and inventive feature or combination of features as hereinbefore described.