GB2526267A

GB2526267A - Dressing for surgical drain

Info

Publication number: GB2526267A
Application number: GB1408550.0A
Authority: GB
Inventors: Stephen Cotton; Robert Cameron Murray
Original assignee: Brightwake Ltd
Current assignee: Brightwake Ltd
Priority date: 2014-05-14
Filing date: 2014-05-14
Publication date: 2015-11-25
Anticipated expiration: 2034-05-14
Also published as: GB2526267B; WO2015173546A1; GB201408550D0

Abstract

A dressing 1 adapted to be fitted around a surgical drain, such as a chest drain, and capable of absorbing exudate from the drain site comprises an absorbent body 22 having a wound-facing foam base layer 32 of hydrophilic open-celled foam, such as polyurethane, to which a cover 34 is bonded to form a substantially enclosed compartment of superabsorbent material 36 between the cover and the base. Exudate at the wound site is able to flow via the base member to the compartment and to be absorbed by the superabsorbent material within the compartment. A radial slot with an opening 10 with radial slits 14 for a drain may be provided. The superabsorbent material may be particles encapsulated between two layers of tissue paper carrier material. A transparent adhesive backing layer 16 and a skin contact layer 18 may extend as a border beyond the absorbent body.

Description

I

DRESSING FOR SURGICAL DRAIN

This invention relates to a dressing for a surgical drain, for instance a chest drain, and in particular to such a dressing that is capable of absorbing exudate from the drain site.

BACKGROUND OF THE INVENTION

A surgical drain is a tube used by surgeons to remove pus, blood or other fluids IC) which may accumulate and become a focus of infection. Drains may be connected to a source of suction or may be aflowed to drain naturally. The drain may remain in place for extended periods, for instance days or even weeks, and a suitable dressing is usually applied around it.

The use of drains is not without disadvantages, notably the fact that the drain may allow infection into the wound. However, in some clinical situations their use is unavoidable.

One particular form of surgical drain is a chest drain, a flexible plastic tube that is inserted through the chest wall and into the pleural space to remove air, fluid or pus from the intrathoracic space.

Chest drains are commonly made from clear plastics like PVC and soft silicone, and have diameters of from a few millimetres to one centimetre or more. A major problem with the use of chest drains is clogging of the drain, and this often leads to the use of larger diameter tubes. However, larger drains require larger incisions to he made in the patient's skin, and this in turn may increase the amount of body fluid that exudes from the incision around the drain tube. If that body fluid is allowed to accumulate it may lead to increased risk of infection, as well as requiring more frequent dressing changes, which may cause discomfort to the patient.

There is therefore an ongoing need for improved dressings for surgical drains that provide for improved management of wound exudate at the drain site, and thereby lead to reduced risk of infection, reduced frequency of dressing changes, and/or

other benefits in relation to the prior art.

BRIEF SUMMARY OF THE INVENTION

According to the invention, there is provided a dressing for a surgical drain, the dressing comprising an absorbent body adapted to be fitted around the drain at a IC) site at which the drain emerges from a patient's body, wherein the absorbent body comprises a base of open-ceed foam and a cover member bonded to the base so as to form a substantiafly endosed compartment between the cover member and the base, which compartment contains a superabsorbent materiaL and wherein exudate at said site is able to flow via the base member to the compartment and to he absorbed by the superabsorhent material within the compartment.

The dressing according to the invention is advantageous primarily in that it provides for effective absorption of exudate emitted from the drain site. Exudate is transported away from that site by the wicking action of the foam base and is absorbed by the superabsorbent material. High quantities of exudate may be absorbed before the dressing needs to be changed, thereby reducing the frequency of dressing changes required.

DETAILED DESCRIPTION OF THE INVENTION

The absorbent body may have any suitable shape and dimensions, depending on the nature of the drain about which the dressing is to be applied, the part of the body to which it is to be applied, etc. Most commonly, however, the absorbent body will be generally circular.

To enable the absorbent body to be fitted around a drain, the absorbent body most preferably is formed with a s lot or the like that extends from the perimeter of the absorbent body to a suitable positbn within the absorbent body, most commonly a substantiafly central position. The slot is thus typically a radial slot, extending from the centre of the absorbent body to its perimeter.

The slot may terminate in an opening, the dirriensions of which are preferably such that the drain is closely received within it, so that the wail of the opening fits closely against the drain. In order to accommodate drains of differing diameter, the opening may be provided with outwardly extending radial slits, IC) The base of the absorbent body comprises an open-celled foam. The foam may he any suitable foam known in the art. Preferably, the foam is a hydrophilic foam.

More preferably, the hydrophilic foam is a polyurethane foam. Most preferably, the foam is an open-celled polyurethane foam. The open cellular structure of the foam allows exudate from the drain site to pass through it. The foam typically has a thickness of 0,5mm to 10mm, preferablyfrom 1mm to 5mm, orfrom 1mm to 3mm, and the foam most preferably has a thickness of about 1mm, about 2mm, or about 3mm.

To further reduce the risk of infection at the drain site, the foam may incorporate an anti-microbial agent. One antimicrobial agent that may be incorporated into the foam is silver. Despite metallic silver being relatively unreactive, ionic silver has been shown to have antimicrobial activity and has been previously used in wound dressings. In use, positively charged silver ions bind to negatively charged sites on proteins and nucleic acids in bacteria. This causes a number of effects, including alteration of the protein structure, rupture of the cell wall and/or cell death. It is believed that silver ions have multiple attack sites, interacting with a number of different functional groups in bacteria, including thiol groups, carboxylates, phosphates, indoles and amines This makes the development of bacterial resistance to silver unusual.

The incorporation of silver into the foam results in the sustained release of low concentrations of silver ions overtime. Such a slow release has been shown to stimulate healing and inhibit the growth of micro-organisms. Any suitable method or form of silver known in the art may be used in the present invention. For example, the silver may be in the form of silver suiphadiazine.

Mother antimicrobial that may be incorporated into the foam is polyhexamethylene biguanide (PHMB; also known as polyaminopropyl biguanide).

PHMB is available as a 20% aqueous solution under the trade name COSMOCIL® CO from Arch Personal Care Products, 70 Tyler Place, South Plainfield, NJ 07080, USA.

The cover member that is bonded to the foam base in order to create the compartment may be of any suitable material. Such materials will typically be synthetic textile materials. A preferred material is a heat-fusible non-woven web, eg of the type known as "dryweb", which may be of polyester.

Bonding of the cover member and the base may be brought about by any suitable means. For instance, the parts of one or both of the juxtaposed surfaces of those components that are to be bonded together may be coated with a suitable adhesive, and the two components then pressed together.

More preferably, however, the two components are bonded by using a fusible web material for the cover member, and apply heat and pressure to that material in the regions in which it is to be bonded to the foam. When the fusible web is pressed against the foam base material and heated, the melting action of the web causes it to bond to the foam base.

Individual pieces of cover member and foam base, both having the shape and dimensions of the finished absorbent body, may be bonded together as just described, with superabsorbent material previously having been positioned between them, in the region that constitutes the compartment of the finished absorbent body. However, it will be appreciated that more commonly manufacturing will be done by applying a sheet of cover member material to a sheet of foam material (again with superabsorbent material at appropriate positions between the two sheets), applying heat and pressure to those materials in patterns that define the shapes of the absorbent body, such that the superabsorbent material is encapsulated between the two sheets, and then cuffing indMdual absorbent bodies from the bonded sheets. The features necessary to permit the absorbent body to be fitted around a drain (eg the slot and central opening) may also be formed during the cutting operation, but may alternatively be introduced later, after assembly of the dressing.

In certain embodiments of the invention, the absorbent body is generally circular, with a radial slot extending from one point on the perimeter of the absorbent body to a central opening. The cover member is bonded to the foam base around the perimeter of the circle, along the margins of the slot, and around the central opening. In this case, the resulting compartment is generally C-shaped.

The compartment contains superabsorbent material. "Superabsorbent material" in the context of the present invention means a material that is capable of absorbing many times its own mass of water (eg more than 100 times, and up to 200, 300, 400, 500 or more times its own mass of water).

Although it should be appreciated that the absorbent body of the present invention may comprise any superabsorbent material, preferred superabsorbent materials are polymeric superabsorbent materials and include alginate, polyacrylate (ie a salt of polyacrylic acid), polyacrylamide copolymers, ethylene maleic anhydride copolymer, carboxymethylcellulose, polyvinylalcohol copolymers, polyethylene oxide and starch-grafted copolymers of polyacrylonitrile.

Many such superabsorbent materials may be used in particulate form. In such cases, the particles may be incorporated into a carrier material, for instance by being encapsulated between two layers of carrier material, eg tissue paper or the like.

An alginate superabsorbent may be sodium or calcium alginate. Alginate superabsorbent is preferably in the form of a non-woven mat.

The most preferred superabsorbent material is sodium polyacrylate polymer.

Sodium polyacrylate polymer is a solid crystalline material, and is preferably incorporated into a layer in the form of particles encapsulated between two layers of carrier material, such as tissue paper. A specific example of a suitable material is Gelok® 14040S/S manufactured by Gelok International Corporation.

Superabsorbent materials comprising particles of super-absorbing polymer encapsulated between two layers of carrier material can be cut into shapes adapted to fit into the compartment of the absorbent body. In the embodiments mentioned above, for instance, in which the compartment is generally C-shaped, a similarly-shaped pice of the superabsorbent material can be accommodated within the compartment.

In addition to the absorbent body, the dressing of the invention will generally also comprise an adhesive skin contact layer, and a backing layer that forms a liquid-impermeable top surface of the dressing. The absorbent body will generally be held between the backing layer and the skin contact layer.

The skin contact layer is the part of the dressing that, in use, is applied to the patient's skin, and will generally carry an adhesive. It is generally preferable that the adhesive that is used is one that is non-adherent and permits the wound dressing to be removed relatively easily and without causing trauma to the drain site and surrounding skin. Thus, the adhesive may be, for instance, a hydrocolloid adhesive, a polyurethane adhesive, a hydrogel or, most preferably, a silicone adhesive, particularly a silicone gel.

Silicone adhesives offer numerous advantages. Most preferably, the silicone adhesive is in the form of a silicone gel of the type generally referred to as a "soft silicone".

Soft silicone adhesives are particularly suited for use as skin contact layers in wound dressings. They are soft, tacthe and conformable, and exhibit good adhesion to dry skin but low adherence to an underlying wound. Thus, the dressing can be applied to a wound and subsequently removed without causing trauma to the wound. Silicone gels are adhesive but do not leave residue on a surface/substrate when removed.

Silicone gels suitable for use as skin contact materials in the present invention may be carried on a layer of melt-blown non-woven material, eg a sheet of melt-blown polyurethane (MBPU), as described in W02007/1 13597.

In such cases, the reverse side of the MBPU may be coated with an adhesive, eg an acrylic adhesive, to affix the silicone geIIMBPU laminate to overlying components of the dressing, eg to the absorbent body and/or a backing layer of the form described below.

The skin contact layer generally extends beyond the absorbent body, to provide a greater contact area between the dressing and the skin. Thus, a border is provided around the absorbent body.

The adhesive may be provided only on the parts of the skin contact layer that form the border around the absorbent body. More commonly, however, the skin contact adhesive is present across the full extent of the dressing.

The skin contact layer is preferably provided with perforations to increase breathability of the dressing, and so lessen the likelihood of maceration of the skin to which the dressing is applied. The perforations may also provide for greater ease of removal of the dressing, and improved flexibility and conformity.

The dressing according to the invention typically comprises a backing layer, which forms a baffler between the wound and the surrounding atmosphere. Any suitable material known in the art may be used for the backing layer.

The backing layer will generally be impermeable to exudate and other liquids, but is preferably permeable to air and moisture vapour. In particular, the backing layer preferably exhibits a relatively high moisture vapour transmission rate (MVTR).

The MVTR of the backing layer may be at least 300g/m2124h, more suitably at least 500g/m2/24h and preferably at least 700g/m2124h at 37°C and 100% to 10% relative humidity difference.

The backing layer is most preferably a plastics film having the desired characteristics. The backing layer may be a polyurethane film.

The backing layer will generally be of the same dimensions as the skin contact layer, that is to say it will generally be larger in size than the absorbent body, such that it extends beyond the edge of the absorbent body on one or more sides.

Preferably, the backing layer extends beyond the edge of the absorbent body on all sides, forming a border around the absorbent body, and is bonded to the peripheral region of the skin contact layer.

The underside of the backing layer may carry an adhesive, eg an acrylic adhesive, to bond the backing layer to underlying components of the dressing, eg to the upper surface of the absorbent body and to the peripheral region of the skin contact layer. Where the backing layer carries an adhesive and overlies the skin contact layer, the skin contact layer may be provided with relatively large openings in order to expose the skin to the adhesive on the underside of the backing layer.

That adhesive (eg acrylic adhesive) may be more adherent than the typically non-adherent adhesive (eg silicone gel) carried by the skin contact layer. By allowing contact of the stronger adhesive with the healthy skin surrounding the wound, the dressing of the invention may be attached more securely to the patient.

In some embodiments, the backing layer may constitute the cover member of the compartment, ie the backing layer may be affixed directly to the foam base, with the compartment being the space between the foam base and the backing layer.

The dressing will generally be supplied with a releasable liner on its underside.

The releasable liner may cover the adhesive portions of the dressing prior to use, and be removed from the dressing immediately before application of the dressing.

This reduces the risk of contamination of the dressing and facHitates handUng of the dressing.

Such releasable liners are commonly used on dressings known in the art, and suitable materials which can be employed in the present invention wifl be famHiar to the skifled worker. For example, the releasable Hner may be of a suitable plastics sheet or a siUconised paper or the like.

The releasable liner may be a single sheet which covers the underside of the dressing. or may he formed of two or more sheets. The releasable liner may further comprise one or more tabs to enable the liner to be easily removed from the dressing before use. In particular, where the releasable liner is formed of two or more parts, the parts may either overlap or abut and extend outwards from the dressing, thus providing an easy method for removal of the releasable liner.

ICC

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a plan view of a dressing according to the invention; Figure 2 is an underside plan view of the dressing of Figure I partially cut away; Figure 3 is a crosssectional view (on an enlargerJ vertical scale for clarity) on the line Ill-Ill in Figure 1; and Figure 4 is a plan view of an absorbent body forming part of the dressing of Figures 1 to 3, showing hidden detail.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring first to Figure 1, a chest drain dressing according to the invention is generafly designated 1, and is circular in form, with a diameter of approximately 15cm. The dressing 1 has a central opening lOthatis connected to the edge of the dressing 1 by an elongate slot 12. In use, as described below, a chest drain is received within the opening 10 such that the walls of the opening abut the drain. A number of short slits 14 extend outwardly from the opening 10, in order to enable the dressing 1 to be fitted around a larger diameter drain.

The dressing 1 comprises a backing layer 16 that constitutes the top (ie nonskin-facing) surface of the dressing 1, an adhesive skin contact layer 18 that, prior to use, is covered by a three part release liner 20ac, and an absorbent body 22, the outline of which is shown in Figure 1, and the structure of which is described in more detail below, with reference to Figures 3 and 4.

As illustrated, the backing layer 16 is transparent, with the result that features of the underlying components (ie the absorbent body 22 and the skin contact layer 18) are visible through it. In particular, the skin contact layer 18 is provided with a regular array of small and large perforations 24a24b (see Figure 2). In Figure 1, these perforations are shown as hidden detail only in part of the drawing, though in reality they would be visible around the full periphery of the dressing 1.

Of course, the backing layer 16 could alternatively be opaque, in which case these underlying features would not be visible when the dressing I is viewed from above, as in Figure 1 The skin contact layer 18 is in the form of a sheet of meltThlown polyurethane that is impregnated with and coated on its underside (as viewed in Figure. 3') with a silicone gel nonadherent adhesive, as described in W02007/113597. The skin contact layer 18 is of the same dimensions as the backing layer 16, such that the skin contact layer 18 and backing layer 16 form a border around the periphery of the dressing 1.

The absorbent body 22 comprises three components: a foam base 32, a cover 34 and a superabsorhent 36.

The foam base 32 is of hydrophilic, open-celled polyurethane foam and is generally circular in shape, save for a radial cut-out 33 that, in the assembled dressing 1, is aligned with the slot 12. The foam base 32 is also provided with a central opening I Oa that constitutes part of the central opening 10 of the assembled dressing. The foam base 32 has a thickness of approximately 2mm.

The cover 34 is a sheet of fusible polyester web that is bonded (by the application of heat and pressure) to the upper surface of the foam base 32 around the periphery of the base 32, along the margins of the cut-out 33 and around the central opening I Oa. The regions over which the cover 34 is bonded to the foam base 32 are indicated by "x" markings in Figure 4.

A generally C-shaped compartment is thus defined between the cover 34 and the foam base 32, and this is occupied by the correspondingly-shaped superabsorbent 36. The superabsorbent 36 comprises particulate polyacrylate polymer encapsulated between two sheets of tissue paper.

The underside of the backing layer 16 is coated with acrylic adhesive by which the backing layer 16 is affixed to the upper surface of the skin contact layer 18 in the border regions of the dressing 1, and to the upper surface of the absorbent body 22 in the central region of the dressing. The large perforations 24b in the skin contact layer around the periphery of the dressing I expose the patients skin to the acrylic adhesive on the underside of the backing layer 16. This provides for more secure attachment of the dressing I to the skin, the relatively strong adherence of the acrylic adhesive where it contacts healthy skin not being a problem as the locations at which this occurs are sufficiently distant from the drain site.

In general terms, the dressing I may be manufactured by a) forming the absorbent body 22, by applying a sheet of cover member material to a sheet of foam material (with pieces of superabsorbent 36 at appropriate positions between the two sheets), applying heat and pressure to those materials in patterns that define the shapes of the absorbent body 22, such that the superabsorbent 36 is encapsulated between the two sheets, and then cutting indMdual absorbent bodies 22 from the bonded sheets; and b) sandwiching the absorbent body 22 between the skin contact layer 18 and the backing layer 16.

The r&ease liners 20a-c can be applied to the skin contact ayer 18 at any IC) convenient stage of manufacture.

The features that permit the dressing 1 to be fitted around a chest drain (ie the slot 12, opening 10 and sflts 14) may be formed in the various components prior to assembly of the dressing 1, but it is generafly more convenient for those features to he formed in a subsequent cutting operation, after assembly of the various components as described above. ndeed, the formation of those features may be done as part of a cutting process in which individual finished dressings are cut from a sheet. Individual dressings may then be sterHa-packaged, eg by gamma--irradiation or ethylene oxide.

In use, the dressing 1 is removed from its packaging and the release liners 20ac removed. The parts of the dressing 1 at opposite sides of the slot 12 are moved slightly apart to allow the dressing I to be Fitted around a chest drain, with the drain occupying the central opening 10 and the skin contact layer 18 facing the patient's skin. Those parts of the dressing 1 are then brought back together and the dressing 1 pressed gently into engagement with the patient's skin.

Any fluid escaping from the drain site contacts the exposed edges of the foam base 32 within the central opening 10. The fluid is transported by wicking action through the foam base 32 and hence comes into contact with the superabsorbent 36, which absorbs the fluid. swelling as it does so. The backing layer 16 is sufficiently thin and deformable to accommodate that swelling. Accumulation of fluid at the drain site is thereby avoided, and the frequency of required dressing changes and the risk of infection at the drain site are reduced.

Claims

Claims I. A dressing for a surgical drain, the dressing comprising an absorbent body adapted to he fitted around the drain at a site at which the drain emerges from a patient's body, wherein the absorbent body comprises a base of openceUed foam and a cover member bonded to the base so as to form a substantiafly endosed compartment between the cover member and the base, which compartment contains a superabsorbent material, and wherein exudate at said site is able to flow via the base member to the compartment and to be absorbed by the IC) superabsorbent material within the compartment.
2. A dressing as claimed in Claim 1, wherein the absorbent body is generaHy cwcular.
3. A dressing as claimed in Claim 1 or Claim 2. wherein the absorbent body is formed with a slot or the like that extends from the perimeter of the absorbent body to a position within the absorbent body.
4. A dressing as claimed in Claim 3, wherein the slot is a radial slot, extending from the centre of the absorbent body to its perimeter.
5. A dressing as claimed in Claim 3 or Caim 4, wherein the slot terminates in an opening, the dimensions of which are such that the drain is, in use, closely received within it, so that the wall of the opening fits closely against the drain.
6. A dressing as claimed in Claim 5, wherein the opening is provided with outwardly extending radial slits.
7. A dressing as claimed in any preceding claim, wherein the base is of pen-cefled polyurethane foam.
8. A dressing as claimed in any preceding claim, wherein the base has a thickness of 0,5mm to 10mm, or from 1mm to 5mm, or from 1mm to 3mm.
9. A dressing as claimed in any preceding claim, wherein the base incorporates an anti-microbial agent.
10. A dressing as claimed in any preceding claim, wherein the cover member is of a synthetic textile material.
11. A dressing as claimed in Claim 10, wherein the synthetic textile material is a heat-fusible non-woven polyester.
12. A dressing as claimed in any preceding claim, wherein the absorbent body is generally circular, with a radial slot extending from one point on the perimeter of the absorbent body to a central opening, the cover member is bonded to the foam base around the perimeter of the circle, along the margins of the slot, and around the central opening, such that the compartment is generally C-shaped.
13. A dressing as claimed in any preceding claim, wherein the superabsorbent material is a material capable of absorbing more than 100 times, and up to 200, 300, 400, 500 or more times its own mass of water.
14. A dressing as claimed in any preceding claim, wherein the superabsorbent material is selected from the group consisting of alginate, polyacrylate (ie a salt of polyacrylic acid), polyactylamide copolymers, ethylene maleic anhydride copolymer, carboxymethylcellulose, polyvinylalcohol copolymers, polyethylene oxide and starch-grafted copolymers of polyacrylonitrile.
15. A dressing as claimed in any preceding claim, wherein the superabsorbent material is in the form of particles incorporated into a carrier material.
16. A dressing as claimed in Claim 15, wherein the particles are encapsulated between two layers of carrier material.
17. A dressing as claimed in Claim 16, wherein the carrier material is tissue paper.
18. A dressing as claimed in any one of Claims 14 to 17, wherein the superabsorbent material is sodium polyacrylate polymer.
19. A dressing as claimed in any preceding claim, further comprising a skin contact layer and a backing layer, the absorbent body being held between the backing layer and the skin contact layer.
20. A dressing as claimed in Claim 19, wherein the skin contact layer carries a non-adherent adhesive.
21. A dressing as claimed in Claim 20, wherein the non-adherent adhesive is a silicone gel.
22. A dressing as claimed in Claim 21, wherein the silicone gel is carried on a layer of melt-blown non-woven material, eg a sheet of melt-blown polyurethane (MBPU).
23. A dressing as claimed in any one of Claims 19 to 22, wherein the backing layer has a moisture vapour transmission rate of at least 300g/m2124h, more suitably at least 500g/m2124h and preferably at least 700g1m2124h at 37°C and 100% to 10% relative humidity difference.
24. A dressing as claimed in any one of Claims 19 to 23, wherein the backing layer is a polyurethane film.
25. A dressing as claimed in any one of Claims 19 to 24, wherein the skin contact layer and the backing layer extend beyond the absorbent body, to provide a border around the absorbent body.
26. A dressing substantially as described herein, and as illustrated in the accompanying Figures.