GB2311014A

GB2311014A - Filtered ostomy bag

Info

Publication number: GB2311014A
Application number: GB9705394A
Authority: GB
Inventors: Rory James Maxwell Smith; Paul Gocher
Original assignee: Welland Medical Ltd
Current assignee: Welland Medical Ltd
Priority date: 1996-03-15
Filing date: 1997-03-14
Publication date: 1997-09-17
Anticipated expiration: 2017-03-14
Also published as: GB9705394D0; GB2311014B; GB9605438D0; EP0836458A1; WO1997034549A1

Abstract

The bag comprises first and second, peripherally sealed sheets 2,4 of waterproof material, the first sheet having an opening 8 for the stoma and one of the sheets having a vent 18 covered by a flatus filter 20, and a third sheet 22 interposed between the other two sheets and sealed to the first sheet, the third sheet serving to divide the bag interior into a first waste-receiving chamber 28 in which opening 18 is located and a second chamber 30 which has an area at least as great as that of the first chamber. The third sheet has perforations, particularly fibrillations or slits, defining a primary filter 34 which allows gas to pass between the chambers, the primary and flatus filters being laterally offset so that the lateral flow path therebetween is greater than the width of the flatus filter.

Description

OSTOMY BAGS This invention relates to ostomy bags and in particular ileostomy bags having a flatus gas filter arrangement.

It is commonplace for colostomy bags to incorporate flatus filters to filter out the noxious components of flatus gases. Such filters are well known and typically comprise activated carbon which adsorbs the noxious components of the flatus gases.

One problem with flatus filters is their tendency to become blocked by waste within the ostomy bag, and once blocked, they often cease to function effectively. In order to overcome this problem, it has been proposed to provide a barrier between the main waste receiving compartment of the bag and the filter to prevent blocking of the filter. Such barriers can be for example in the form of a hydrophobic film which is permeable to gases but which does not allow liquid and solid wastes to pass through. Alternatively, arrangements are known in which a barrier wall has an opening or openings which are either positioned so that waste coming into the bag cannot directly contact the filter, or are of a dimension such that waste is not allowed to pass through the opening(s). Exemplary of such arrangements are GB 2215608 and GB 2149306.

Although flatus gas filtering arrangements are usually relatively effective with colostomy bags, the more liquid waste produced by ileostomy patients can create severe blockage problems, with the result that ileostomy bags currently in use do not have flatus gas venting arrangements. It will be noted in this respect that the bags illustrated in GB 221 5608 nor GB 2149306, which do have flatus filters, are not ileostomy bags since they do not have a drainage opening through which liquid waste can be removed.

The absence of a flatus gas venting arrangement means that in use the build up of flatus gases within the bags causes the bags to balloon, creating discomfort and an unsightly and embarrassing bulge in the patient's clothing.

Thus, at the present time, there remains a need for a flatus gas filtering arrangement which can be used with ileostomy bags and which shows improved resistance to blocking with liquid and/or solid waste. It is an object of the present invention to provide such an arrangement.

According to a first embodiment of the invention there is provided an ostomy bag comprising first and second sheets of a waterproof, preferably polymeric, material sealed together around their peripheral margins; the first sheet having an opening for receiving bodily waste from a stoma, the opening being surrounded by fastening means for fastening the bag to the skin of a patient about the stoma; the first or second sheets having a vent covered by a flatus filter; a third sheet being interposed between the first and second sheets and being sealed to the first sheet; the third sheet serving to divide the interior of the bag into a first waste receiving chamber in which the said opening is located, and a second chamber from which flatus gases pass to the vent, the second chamber having an area which is at least as great as the area of the first chamber; the third sheet having a perforation or plurality of perforations defining a primary filter allowing the passage of gas between the first and second chambers; wherein the primary filter and flatus filter are not superimposed, but are laterally offset as to define a lateral flow path therebetween which is greater than the width of the flatus filter.

In addition to being sealed to the first sheet, the third sheet is preferably also sealed to the second sheet.

It is particularly preferred that the first, second and third sheets are of the same size, the third sheet being sealed to the first sheet by means of a first seal and the first, second and third sheets being sealed together by means of a second seal which is formed outwardly of the first seal.

The seals are typically formed by means of welding, for example RF welding. Thus, when ail three sheets are of the same size, the first and third sheets can be sealed together by means of an inner weld line, whereas the first, second and third sheets can be secured together by means of an outer weld line.

The ostomy bag is preferably a drainable ostomy bag and has a sealable drainage opening at a lower end thereof. Thus the bag is particularly suitable for use with ileostomy patients producing high volumes of essentially liquid waste.

The third sheet is typically sealed to the first and second sheets around substantially its entire peripheral margins, provided that when the ostomy bag is a drainable ostomy bag having a drainage opening, the third sheet need not be sealed to the first and second sheets at the drainage opening.

The first chamber typically has an area which is between 75% and 99% of the area of the second chamber. More usually, the area of the first chamber will be 85% to 99% of the area of the second chamber.

The primary filter and flatus filter are preferably both located at the upper end of the ostomy bag above the opening for receiving stoma I waste.

By upper end in the present context is meant the end of the ostomy bag which would normally be uppermost when the bag is fitted to a patient.

The flatus filter is preferably secured to the exterior of the bag, but preferably is concealed within a comfort layer, if such is present. As a further protection to the flatus filter, a hydrophobic filter may be arranged to cover the vent on the inside of the bag wall. The hydrophobic filter can, for example, take the form of a hydrophobic paper filter, for example a material of the type sold by Whatman under the code Whatman F513-01.

The perforations in the third sheet defining the primary filter can be of any shape but preferably are in the form of fibrillations. The fibrillations preferably have a maximum dimension in the range 0.4mm to 5mm, preferably 1 mum to 3mm, for example approximately 2mm. Where the perforations are not fibrillations or slits, but for example are circular or square in form, they may have a maximum dimension of up to 2mm, or preferably up to 1 mm and a minimum dimension of 0.4mm.

The primary filter preferably represents the only opening between the first and second chambers.

The lateral flow path between the primary filter and the flatus filter advantageously is at least 4cm and more preferably is at least 5cm in length.

The invention will now be illustrated by reference to the accompanying drawings in which: Figures 1 A to 1 D are views from the rear, side, front and top respectively of a drainable ileostomy bag according to one embodiment of the invention; Figure 2 is an exploded view of the embodiment of Figures 1 A to 1 D.

Figure 3 is an exaggerated sectional elevation along the line I-I of Figure 1A; and Figure 4 is an exaggerated sectional elevation along the line ll-ll of Figure 1A.

Referring to the drawings, the ileostomy bag comprises first and second sheets of polymeric film 2,4 sealed together around their peripheral margins 6. Sheets 2 and 4 are formed from a trilaminate of ethylene vinyl acetate/polyvinylidene dichloride (PVDC)/ethylene vinyl acetate (EVA). The EVA/PVDC/EVA film is impermeable to both liquids and gases, the PVDC layer serving as a gas barrier. A suitable grade of trilaminate film is the 100 micron thick F513-01 grade supplied by Grace GmbH of Larderstedt Germany.

The first sheet 2 has a central opening 8 which fits about the stoma of a patient, and functions as the inlet for receiving stomal waste.

Surrounding the opening 8 is an adhesive flange 10 of conventional construction. Thus the adhesive flange has a backing layer 12, a hydrocolloid adhesive layer 14 and a peelable release layer 16. The hydrocolloid flange is used in conventional fashion to fasten the ostomy bag to the patient's body wall. At a location on the upper end of the first sheet 2, there is a vent hole 1 8 which is covered on the exterior surface of sheet 2 by a flatus filter 20. Flatus filter 20 may be of conventional design and contain an activated carbon adsorbent. A suitable filtering medium is Type T90 Activated Carbon Cloth available from Carbon Cloth Ltd.

A comfort layer of non woven fabric 5 is secured to and overlays the first sheet 2 in conventional fashion.

A third sheet 22 is interposed between the first and second sheet 2,4, and is welded to the first sheet 2 and comfort layer 5 at its peripheral margins by an inner weld line 24 and to both the first and second sheets 2,4 and the comfort layer 5 by the outer weld line 25. In the region of the flatus filter 20, an annular weld strip 26 connects the first and third sheets 2,22 and the comfort layer 5.

The third sheet 22 acts to divide the interior of the ostomy bag into a first chamber 28 and a second chamber 30. Since the area within the outer weld line 25 is greater than the area within the inner weld line 24, the area of the second chamber is correspondingly larger than the area of the first chamber.

An opening 32 in the wall of the third sheet provides gas communication between the second chamber 30 and the vent 18. A hydrophobic filter 33 formed from a treated filter paper (Whatman grade F513-01) covers the opening 32.

Offset laterally from the flatus filter, on the opposing margin of the bag, is primary filter 34. Primary filter 34 comprises a plurality of fibrillations in the third sheet 22. The fibrillations in this case are arranged in a circular array although this is not necessary. They could instead be arranged in a rectangular array or indeed any other convenient shape. The fibrillations typically are from about 1 mm to about 3mm in length and are sufficiently large to allow free flow of gas therethrough, but act to inhibit or prevent solid and much liquid waste from passing from the first chamber 28 into the second chamber 30.

The manner in which the ostomy bag is constructed is best appreciated from the exploded view in Figure 2. Thus the first step in the process involves the welding together of the hydrocolloid adhesive flange 10, comfort layer 5 and the first sheet 2 by means of an annular weld (not shown) around the opening 8 to form a first intermediate assembly. The third sheet 22, which has been pre-fibrillated to form primary filter 34 and has had attached thereto the hydrophobic paper filter 33, is then welded to the first intermediate assembly along inner weld line 24 to form a second intermediate assembly. (Note that in Figure 2, the weld lines are depicted for the sake of clarity as being suspended above the sheets, although of course in reality they are in the plane of the sheets.) Inner weld line 24 has a short arcuate extension 24a which partially surrounds the primary filter 34, and the purpose of which will become apparent. Finally, the second sheet 4 is welded to the second intermediate assembly along outer weld line 25.

In use, liquid waste passes through the opening 8 into the first chamber 28. As the bag fills up, or if the patient adopts a reclining position, some liquid waste may seep through the primary filter 34. However, because the flatus filter 20 is offset laterally from the primary filter, liquid passing through the primary filter 34 does not come into contact directly with the flatus filter and this reduces the chances of blockage occurring.

Flow of liquid from the primary filter towards the flatus filter is further inhibited by the arcuate extension 24a of the inner weld line 24 which acts as a dam and diverts the liquid in a downwards direction away from the flatus filter. In the event that liquid passes around the second chamber 30 towards vent 18, a further filtering action is carried out by the hydrophobic paper filter 32 thereby offering a further means of preventing blockage of the flatus filter.

The gas flow path through the bag is shown by means of the dotted line 36. Thus gas passes into the bag along with the other stomal waste products through opening 8, and then around the dam formed by arcuate weld line extension 24a, through primary filter 34, across the bag and out through hydrophobic paper filter 33, vent hole 32, vent hole 1 8 and flatus filter 20. Any noxious substances in the flatus gases are removed by adsorption on the activated carbon in the flatus filter.

In the bag illustrated, the second chamber 30 has a greater area than the first chamber 28 and one consequence of this is that even if the bag balloons due to excessive quantities of flatus gas, the clearance between the third and second sheets 22,4 is maintained thereby keeping the gas flow path to the bag exterior open. A further advantage of the arrangement shown is that if the second chamber 30 does fill with liquid, manipulation of the bag by the patient can unblock the primary filter and also the hydrophobic filter 32.

The arrangement shown in Figures 1 to 4 is intended primarily for use with ileostomy bags but the filter arrangement of the invention may also have benefits with colostomy bags.

It will readily be appreciated that numerous modifications and alterations may be made to the bag illustrated without departing from the principles underlying the invention and also modifications and alterations are intended to be embraced by this application.

Claims

1. An ostomy bag comprising first and second sheets of a waterproof material sealed together around their peripheral margins; the first sheet having an opening for receiving bodily waste from a stoma, the opening being surrounded by fastening means for fastening the bag to the skin of a patient about the stoma; the first or second sheets having a vent covered by a flatus filter; a third sheet being interposed between the first and second sheets and being sealed to the first sheet; the third sheet serving to divide the interior of the bag into a first waste receiving chamber in which the said opening is located, and a second chamber from which flatus gases pass to the vent, the second chamber having an area which is at least as great as the area of the first chamber; the third sheet having a perforation or plurality of perforations defining a primary filter allowing the passage of gas between the first and second chambers; wherein the primary filter and flatus filter are not superimposed, but are laterally offset as to define a lateral flow path therebetween which is greater than the width of the flatus filter.

2. An ostomy bag according to claim 1 wherein the waterproof material is polymeric.

3. An ostomy bag according to claim 1 or claim 2 wherein, in addition to being sealed to the first sheet, the third sheet is also sealed to the second sheet.

4. An ostomy bag according to any one of the preceding claims wherein the first, second and third sheets are of the same size.

5. An ostomy bag according to claim 4 wherein the third sheet is sealed to the first sheet by means of a first seal and the first, second and third sheets are sealed together by means of a second seal which is formed outwardly of the first seal.

6. An ostomy bag according to any one of the preceding claims wherein the seals are formed by means of welding, for example RF welding.

7. An ostomy bag according to claim 6 wherein all three sheets are of the same size and wherein the first and third sheets are sealed together by means of an inner weld line, whereas the first, second and third sheets are secured together by means of an outer weld line.

8. An ostomy bag according to any one of the preceding claims wherein a portion of the third sheet is interposed between the second chamber and the vent, the said portion having an opening therein through which flatus gases can pass to the vent.

9. An ostomy bag according to any one of the preceding claims wherein the third sheet is sealed to the first and second sheets around substantially its entire peripheral margins, provided that when the ostomy bag is a drainable ostomy bag having a drainage opening, the third sheet need not be sealed to the first and second sheets at the drainage opening.

10. An ostomy bag according to any one of the preceding claims wherein the first chamber has an area which is between 75% and 99% of the area of the second chamber.

11. An ostomy bag according to claim 10 wherein the area of the first chamber is 85% to 99% of the area of the second chamber.

12. An ostomy bag according to any one of the preceding claims wherein the primary filter and flatus filter are both located at the upper end of the ostomy bag above the opening for receiving stomal waste.

1 3. An ostomy bag according to any one of the preceding claims wherein the flatus filter is secured to the exterior of the bag.

14. An ostomy bag according to any one of the preceding claims wherein a hydrophobic filter is arranged to cover the vent on the inside of the bag wall.

1 5. An ostomy bag according to claim 8 wherein a hydrophobic filter is arranged to cover the vent on the inside of the said portion of the third sheet.

16. An ostomy bag according to claim 14 or claim 15 wherein the hydrophobic filter takes the form of a hydrophobic paper filter.

17. An ostomy bag according to any one of the preceding claims wherein the perforations in the third sheet defining the primary filter are in the form of fibrillations.

18. An ostomy bag according to claim 17 wherein the fibrillations have a maximum dimension in the range 0.4mm to 5mm, preferably 1 mm to 3mm, for example approximately 2mm.

19. An ostomy bag according to any one of the preceding claims wherein the primary filter represents the only opening between the first and second chambers.

20. An ostomy bag according to any one of the preceding claims wherein the lateral flow path between the primary filter and the flatus filter is at least 4cm and more preferably is at least 5cm in length.

21. An ostomy bag according to any one of the preceding claims which is a drainable ostomy bag having a sealable drainage opening at a lower end thereof.

22. An ostomy bag substantially as described herein with reference to the accompanying drawings.