GB2313317A

GB2313317A - Speaking valve assembly and cap therefor

Info

Publication number: GB2313317A
Application number: GB9709872A
Authority: GB
Inventors: Mark William Turner
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1996-05-22
Filing date: 1997-05-15
Publication date: 1997-11-26
Anticipated expiration: 2017-05-15
Also published as: FR2748939A1; GB2313317B; GB9610729D0; GB9709872D0

Abstract

A speaking valve for a tracheostomy tube has a valve unit 21 containing a flexible diaphragm one-way valve 34 hinged onto a housing 1. A cap 2 with a domed roof 40 and four catches 45 to 48 is clipped onto the valve unit 21, the roof being spaced away from the end of the valve unit so that inhaled air is drawn in on all sides radially, rather than axially.

Description

SPEAKING VALVES This invention relates to speaking valves.

A patient breathing via a tracheostomy tube is usually unable to speak because exhaled air passes out through the tube rather than via the vocal folds. In order to enable these patients to breath, it is common practice for a speaking valve to be attached to the end of a modified tracheostomy tube where this emerges from the patient's neck. The valve is a oneway valve allowing normal inhalation but closing to prevent exhalation from the external end of the tube. In this way, exhaled air can pass through the vocal folds, rather than through the tube. Examples of such speaking valves are described in, for example, US4325366, GB2164424, GB2214089, EP78685, EP214243, EP18461, DE2505123 and DE3SO3874.

Speaking valves are often worn for prolonged periods so it is important that they are as inconspicuous as possible. Another problem generally with breathing via a tracheostomy tube is that the inhaled breath is relatively cold and dry compared with normal breathing via the nose. Although this effect can be reduced by the use of a heat and moisture exchange device (HME), this device increases the overall distance by which the tube projects from the patient's neck. Also, an HME is not suitable for use with a speaking valve because the amount of exhaled air passing through the HME is reduced by the one-way action of the valve, thereby substantially reducing the warmth and moisture retained in the HME exchange element.

It is an object of the present invention to provide an improved speaking valve.

According to one aspect of the present invention, there is provided a speaking valve assembly having a generally tubular body and a one-way valve element arranged to enable gas flow through the assembly during inhalation and substantially to prevent gas flow through the assembly during exhalation, one end of the body being provided with a coupling adapted for coupling with the end of a tracheostomy tube, the other end of the body having a substantially axial opening by which gas enters the assembly, the assembly including a removable cap member that can be coupled with the other end of the body, and the cap member being arranged to reduce the amount of gas inhaled into the assembly from an axial direction and to enable gas to enter from a substantially radial direction.

The cap member is preferably arranged to enable gas to enter the assembly from all sides. The cap member preferably has a roof spaced axially away from the end of the body, the roof may be domed away from the valve body. The cap member preferably has a plurality of catches arranged to engage the sides of the valve body. The cap member may have a spigot extending therefrom by which gas can be introduced into a space between the cap member and the body. The spigot preferably extends radially outwardly of the cap member. The body may comprise a housing at the one end of the body and a valve unit at the other end of the body, the valve unit containing the one-way valve element, and the valve unit being removably fastened onto an end of the housing. The valve unit may be retained with the housing by a hinge member. The cap member is preferably coupled on the valve unit. The one-way valve element may include a flexible diaphragm.

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

A speaking 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 side elevation view of the assembly; Figure 2 is a sectional side elevation view of the assembly without the cap and with the valve unit opened; Figure 3 is an end elevation of the assembly shown in Figure 2, along the arrow III; Figure 4 is an end elevation view of the cap along the arrow IV of Figure 1; Figure 5 is a sectional side elevation view of the cap along the line V-V of Figure 4; Figure 6 is a sectional side elevation of an alternative cap; and Figure 7 is a plan view of the alternative cap of Figure 6.

With reference to Figures 1 to 5, the speaking valve assembly comprises a valve body 1 and a removable cap 2, which is normally attached to the valve body but which can be removed if desired. The valve body 1 has a tubular housing 10 about 20mm long and of circular section, with an external diameter of about 18mm and a small taper of about 2". A bore 11 extends along the length of the housing, the right-hand end of the bore, over a distance of about 15mum, tapering gradually at an angle of about 1.5" from its right-hand end where it has a larger internal diameter. At its left-hand end, the bore ii tapers at a greater angle, of about 20 , in the opposite sense so that it has a larger diameter at its left-hand end.

An internal annular step 13 around the bore 11 forms a junction between its right-hand and left-hand ends. Two orthogonally-arranged struts 14 extend diametrically across the housing atthestep 13.

A radial flange 15 projects from the extemal surface of the housing 10 approximately in line with the internal step 13. The flange 15 has two long sides 16 and 17 and two shorter sides 18 and 19, the longer sides and one of the shorter sides being bowed outwardly away from one another, whereas the other shorter side 19 is cut away to form a shallow concave recess. Four shallow lugs 20 project from the external surface at spaced locations around the housing 10 a short distance to the left of the flange 15.

The valve body 1 also includes a valve unit 21 attached with the housing 10 by a flexible web 22, which is joined with the external surface of the housing in the middle of one ofthe shorter sides 18 ofthe flange 15. The valve unit 21 comprises a dish-shape component 23 having a peripheral wall 24 projecting from one side. The internal diameter of the wall 24 is the same as the external diameter of the housing 10 to the left of the flange 15, the wall having two shallow grooves 25 and 26 extending over about 90" and aligned to receive the lugs 20 as a snap fit. Two arc-shape cavities 27 and 28 are moulded within the thickness of the wall 24 behind the grooves 25 and 26 respectively, so as to make the wall more resilient along these regions. The periphery of the component 23 has substantially the same shape as the flange 15 except for the side 19 of the flange where there is a larger overlap by the component 23 to enable access to the edge of the valve unit by the thumb or finger for removal. The component 23 has a central aperture 29 of circular shape and diameter about 13mm with a shallow annular rib 30 about 0.26mm high extending around the outside of the aperture. A bar 31 extends diametrically across the aperture 29 and supports a tapered stake 32, midway along its length. The stake 32 projects to the left in Figure 2 or inwardly of the valve body when the valve unit 21 is folded down and fastened on the housing 10. The base 33 of the stake 32 is flat, projecting to either side of the bar 31, and is located above, or to the left of, the upper surface of the rib 30 by a small distance of about 0.25mm. Two short lugs 36 project inwardly from opposite sides of the aperture at right-angles to the bar 31.

The valve unit 21 also includes a valve element in the form of a thin flexible diaphragm 34 of neoprene or a similar material. The diaphragm 34 is circular, with a diameter of about 16mm, that is, larger than that of the aperture 29. The diaphragm 34 has a central hole 35 that fits under the base 33 of the stake 32, the edge of the diaphragm resting lightly on the rib 30.

The entire valve body 1, including the valve unit 21, except for the diaphragm 34 is a one-piece moulding of a plastics material, such as high density polyethylene.

With reference now to Figures 4 and 5, the cap 2 is dished with an imperforate, convex roof 40 domed away from the valve body, and with four bowed sides 41 to 44. One pair of opposite sides 41 and 42 is longer than the other pair 43 and 44, giving the cap a generally rectangular shape. Four catches 45 to 48 project down by a distance of about 8mm, two catches being located along each of the two longer sides 41 and 42. Each catch 45 to 48 is resilient and has a recess 49 shaped to receive the edge of the valve unit 21. When clipped onto the valve unit 21, the edge of the roof 40 is of the same shape as the valve unit, projecting beyond the edge of the valve unit by about lmm. The roof 40 of the cap 2 is spaced forwardly of the valve unit 21 by about 2mm so that there is space for air flow between the underside of the cap and the upper surface of the valve unit.

In use, the right-hand end of the valve housing 10 is pushed onto a male, tapered coupling (not shown) on the end of a tracheostomy tube. When the patient inhales, the diaphragm 34 is pulled inwardly, to the right, at its edges away from the rib 30, allowing air to flow through the housing. The rib 30 preferably has a number of small notches 37 formed around its circumference. These notches 37 allow a small bleed of air out of the valve during exhalation but help the diaphragm 34 lift away from the rib in a more predictable manner.

The slightly floppy nature of the diaphragm 34 means that it requires some exhalation pressure to bring it into close contact with the rib 30. Inward displacement of the diaphragm 34, on inhalation, is limited by engagement with the struts 14. Inhaled air is drawn into the assembly radially around the edge of the cap 2 from all sides, rather than axially as would be the case if the cap were not present. For this treason, the air drawn into the assembly is taken from a region close to the patient's neck, where it is warmer and moister than ambient air at a greater distance from the patient. The fact that air is admitted to the assembly around the entire periphery of the cap 2 reduces the risk of the speaking valve being accidentally occluded, such as by clothing or bedding.

When the patient exhales, the positive pressure within the housing 10 forces the diaphragm 34 forwardly, into contact with the rib 30, the bar 31 and the lugs 36. Once the pressure of the air is sufficient to cause the diaphragm 34 to seal against the rib 30, most of the exhalation flow through the valve assembly is prevented, except for the small bleed through the notches 37. At very low positive pressure within the housing, however, there will be some seepage of air between the diaphragm 34 and the rib 30 because of the flexible nature of the diaphragm and the fact that it requires is a greater positive air pressure to flatten the diaphragm against the rib.

The cap 2 conceals the aperture 29 and the moving diaphragm 34 and thereby makes the valve assembly less conspicuous. If desired, the cap 2 could be coloured to match the colour of the patient's skin or clothing. The cap 2 also has the advantage of reducing the risk of flying insects being inhaled into the valve.

When it is necessary to clean the valve assembly, the valve unit 21 is simply unclipped from the housing 10 and is hinged up on the web 22. This may be done either with the cap 2 in place or after having removed it. The valve unit could also incorporate a filter (not shown) within the aperture 29, on the external side of the diaphragm 34.

The cap could be modified, as shown in Figures 6 and 7, by having a radiallyextending spigot 50 moulded with the roof 51 of the cap 2'. The spigot 50 opens into the underside of the roof 51 and is shaped at its outer end to be inserted within oxygen tubing (not shown) so that oxygen can be administered to the patient via the spigot for mixing u ith inhaled ambient air from around the edge of the cap. It is advantageous to supply oxygen in this way, by means of an external cap, because there is no risk of pressure from the gas supply building up within the valve, as could be the case where the oxygen inlet opens between the valve element and the patient. The cap could instead be connected to a humidifier or nebulizer so that moisture or drugs could be administered.

Claims

1. A speaking valve assembly having a generally tubular body and a one-way valve element arranged to enable gas flow through the assembly during inhalation and substantially to prevent gas flow through the assembly during exhalation, one end of the body being provided with a coupling adapted for coupling with the end of a tracheostomy tube, the other end of the body having a substantially axial opening by which gas enters the assembly, wherein the assembly includes a removable cap member that can be coupled with the other end of the body, and wherein the cap member is arranged to reduce the amount of gas inhaled into the assembly from an axial direction and to enable gas to enter from a substantially radial direction.

2. An assembly according to Claim 1, wherein the cap member is arranged to enable gas to enter the assembly from all sides.

3. An assembly according to Claim 1 or 2, wherein the cap member has a roof spaced axially away from the end of the body.

4. An assembly according to Claim 3, wherein said roof is domed away from the valve body.

5. An assembly according to any one of the preceding claims, wherein the cap member has a plurality of catches arranged to engage the sides of the valve body.

6. An assembly according to any one of the preceding claims, wherein the cap member has a spigot extending therefrom by which gas can be introduced into a space between the cap member and the body.

7. An assembly according to Claim 6, wherein the spigot extends radially outwardly of the cap member.

8. An assembly according to any one of the preceding claims, wherein the body comprises a housing at said one end of said body and a valve unit at the other end of said body, wherein the valve unit contains said one-way valve element, and wherein said valve unit is removably fastened onto an end of said housing.

9. An assembly according to Claim 8, wherein said valve unit is retained with said housing by a hinge member.

10. An assembly according to Claim 8 or 9, wherein said cap member is coupled on said valve unit.

11. An assembly according to any one of the preceding claims, wherein said one-way valve element includes a flexible diaphragm.

12. A speaking valve assembly substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

13. A speaking valve assembly substantially as hereinbefore described with reference to Figures 1 to 5 as modified by Figures 6 and 7 of the accompanying drawings.

14. A cap for a speaking valve assembly according to any one of the preceding claims.

15. A cap member for a speaking valve assembly substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

16. A cap member for a speaking valve assembly substantially as hereinbefore described with reference to Figures 1 to 5 as modified by Figures 6 and 7 of the accompanying drawings.

17. Any novel feature or combination of features as hereinbefore described.