Stoma discharge collection apparatus

Abstract

Stoma discharge collection apparatus comprising an annular flange 20 having an outer face 21 for adhering to a user’s skin surrounding a stoma, an inner face 22 for connection to a collection bag (1,

Description

TECHNICAL FIELD OF THE INVENTION This invention relates to apparatus for collecting the discharge from an abdominal stoma, and more particularly an annular flange for use in such apparatus. BACKGROUND A stoma is an opening in the abdominal wall to which the digestive tract has been surgically attached. An external bag can then be attached to the abdomen to collect material discharged from the stoma. People may require a stoma for a variety of reasons. In Crohn's disease for example, the diseased colon (large intestine) may be surgically bypassed in a procedure known as a colostomy. The collection bag is then referred to as a colostomy bag. More infrequently, in treatment of ulcerative colitis for example, the ileum (small intestine) may be connected to a stoma so that digestive matter does not need to pass through the colon. In this case the procedure is called an ileostomy and the collection bag is referred to as an ileostomy bag. Two types of collection bag are in general use. In one type the bag is provided with an opening which is adhesively attached to the skin surrounding the stoma. The bag is then detached and disposed of at regular intervals. Another type of bag comprises an annular flange which is adhered to the skin for a longer period, usually one or two days, and a detachable pouch used to catch the digestive waste can be replaced at shorter intervals. Detachable bags are normally single use, but drainable bags which can be emptied through a bottom opening and reused are also available. Users of such known collection systems often find that the weight of the contents causes the skin adhesive to fail as the bag fills up, resulting in frequent leaks. Recently, manufacturers have attempted to address the leakage problem by providing an electronic alarm system which alerts the user to potential leakage, e.g. via a mobile phone, but these add cost and complication and users may find that they are aware of the leak before an alarm is given. SUMMARY OF THE INVENTION When viewed from one aspect the present invention proposes stoma discharge collection apparatus which includes an annular flange provided with a non-return valve to prevent back-flow of material discharged from the stoma. The non-return valve preferably has two flexible impervious wall members disposed face-to-face and resiliently urged into a normal state such that there is little or no through passage between them. BRIEF DESCRIPTION OF THE DRAWINGS The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a rear view of a known form of collection bag for receiving material discharged from a stoma; Figure 2 is a rear view of an annular flange for connection to the collection bag; and Figure 3 is a cross-sectional view III-III of the annular flange shown in Fig. 2. DETAILED DESCRIPTION OF THE DRAWINGS Referring firstly to Fig. 1, stoma discharge collection apparatus includes a collection bag 1 for receiving material discharged from a stoma, which has flexible mutually opposed front and rear walls 2 and 3 connected together around their peripheral edges 4. The rear wall 3 contains an inlet aperture 5 which is surrounded by an attachment area 6 to adhere to a user's skin surrounding a stoma. The attachment area 6 is typically coated with a suitable medical grade contact adhesive which, prior to use, is protected by a peelable cover 7. If required, the size of the inlet aperture 5 may be enlarged by cutting around one or more guide lines 8 prior to use. In the reusable bag which is shown, the walls 2 and 3 are extended to provide a bottom outlet 9 which may be temporarily closed, for example by mutually adherable strips 10 and 11 and a retaining clip 12. The collection bag can therefore be emptied and re-sealed at convenient intervals allowing the bag to be reused several times without detachment from the user. In single use bags, however, the bottom outlet 9 is omitted. The stoma discharge collection apparatus also includes an annular flange, also referred to as a 'ring' or 'donut', which is shown in Fig.s 2 and 3. The annular flange 20 has an outer face 21 to adhere to a user's skin surrounding a stoma, an inner face 22 for connection to the attachment area 6 of the collection bag 1, and an inner margin 23 joining the inner and outer faces. The outer face 21 will normally be provided with a medical grade contact adhesive, protected by a peelable backing, for attaching the flange to a user's skin. The inner face 22 may also be provided with a similar contact adhesive, protected by a peelable backing, for attaching the flange to the rear wall 3 of the bag 1. The inner margin of the annular flange is provided with a nonreturn valve 40 to prevent back-flow of material discharged from the stoma. The non-return valve 40 comprises a one-piece thinwalled impervious elastomeric tube, e.g. formed of a medical grade elastomer. The valve is preferably integrally moulded with the annular flange 20, but may also be a separate component which is sealably bonded to the inner margin of the flange 20 using a suitable medical grade adhesive. The tube 40 comprises two opposing flexible flat wall members 41 and 42 which are connected to each other along opposite edges 43 and 44 extending along the length of the tube. The tube is manufactured in such a way that, in its normal relaxed state, the flat walls 41 and 42 are disposed close to each other and, under light pressure, lie in mutual face-to-face contact due to the resilience of the elastomeric material. The lower end of the tube 40 defines a slot-shaped opening 45. At the upper end of the tube 40, the walls 41 and 42 diverge and thicken to define an inlet portion 46 which is sealably connected to the inner margin 23. The tube 40 preferably has a hydrophobic coating which has a static contact angle to water of at least 120°. Most preferably a superhydrophobic coating is used which has a static contact angle to water of at least 150°. Such coatings are highly effective for repelling the discharge from a stoma and significantly reduce the chance of back-flow and leakages. The annular flange 20 is attached to the bag 1 with the tube 40 inserted into the bag trough the inlet aperture 5. Liquid material which is discharged from the stoma enters the tube 40 through the inlet portion 46 and forces the flat walls 41 and 42 to move apart permitting unimpeded flow into the collection bag 1. However, fluid flow in the opposite direction is prevented by the close surface contact between the walls 41 and 42. Such back-flow exerts increasing pressure on the external surfaces of the two walls 41, 42 and urges them towards each other preventing flow of material back through the annular flange and preventing a rise in pressure at the flange-to-skin interface which often causes leaks. The opening and closing pressure of the non-return valve may be varied by changing the thickness of the opposing edges of the two walls at the outlet end of the tube 40. If, for example, the said edges are bounded by opposing ribs the opening pressure will be greater than if the ribs are omitted but the chances of the valve being forced open by high back-pressure may be lessened. Although the annular flange and valve are preferably supplied as a separate component for use with a discharge collection bag it would be possible to supply the bags already fitted with a flange and valve. Whilst the above description places emphasis on the areas which are believed to be new and addresses specific problems which have been identified, it is intended that the features disclosed herein may be used in any combination which is capable of providing a new and useful advance in the art. ********

Claims

1. Stoma discharge collection apparatus which includes an annular flange (20) having an outer face (21) to adhere to a user's skin surrounding a stoma, an inner face (22) for connection to a collection bag (1) for receiving material discharged through the stoma, and an inner margin (23) joining the inner and outer faces,wherein the inner margin (23) of the annular flange is provided with a non-return valve (40) to prevent back-flow of material discharged from the stoma,wherein the non-return valve (40) comprises flexible impervious wall members (41, 42) disposed face-to-face and resiliently urged into a normal state such that there is little or no through passage between them.

2. The stoma discharge collection apparatus of claim 1 wherein the outer face (21) of the annular flange is provided with a contact adhesive protected by a peelable backing.

3. The stoma discharge collection apparatus of claim 1 or 2 wherein the inner face (22) of the annular flange is provided with a contact adhesive protected by a peelable backing.

4. The stoma discharge collection apparatus of claim 1, 2 or 3 wherein the non-return valve (40) includes an inlet portion (46) which is sealably connected to the inner margin (23) of theannular flange (20) for ingress of fluid to the interface of the flexible impervious wall members (41, 42), whereby in-flowing fluid will force the said wall members apart to permit flow between them whereas fluid flow in the opposite direction is prevented by mutual surface contact between the members.

5. The stoma discharge collection apparatus of any preceding claim wherein the non-return valve (40) has a hydrophobic coating.

6. The stoma discharge collection apparatus of claim 5 wherein the hydrophobic coating has a static contact angle to water of at least 120°.

7. The stoma discharge collection apparatus of any of claims 1 to 4 wherein the non-return valve (40) has a superhydrophobic coating.

8. The stoma discharge collection apparatus of claim 7 wherein the superhydrophobic coating has a static contact angle to water of at least 150°.

9. The stoma discharge collection apparatus of any preceding claim wherein the annular flange (20) is connected to a collection bag (1) for receiving material discharged through the stoma.?|c ?|c sfc ?|c ?|c ?|c

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