WO1993004649A1

WO1993004649A1 - Wounds dressings

Info

Publication number: WO1993004649A1
Application number: PCT/GB1992/001620
Authority: WO
Inventors: Christopher Robey Tucker
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-09-04
Filing date: 1992-09-04
Publication date: 1993-03-18
Anticipated expiration: 1994-03-04
Also published as: GB2277036A; GB9406717D0; GB9119003D0; AU2483092A

Abstract

A dressing for a wound comprising a pliable and resilient containment member (10) having an under surface (14) and a top surface (12) for surrounding and covering a wound (16) wherein the under surface may match the contours of the surrounds of the wound and the top surface may match the contours of a patient's body. The under surface may define a void (20) for location immediately above the wound and an aperture (23) may extend down from the top surface and communicate with the void.

Description

WOUND DRESSINGS

This invention is concerned with wound dressings for body parts and in addition, wound dressings being prosthetic devices, prophylactic devices and devices for 5 both the prevention and treatment of decubitus ulcers.

Large and complex wounds may arise from a variety of causes, such as gunshots or road accidents, or medical problems such as cancers, especially when extensive surgery has taken place in an effort to contain the 10 disease. The greater the area of the wound, the more likely is it that relative movement will be needed between the healthy tissues surrounding the wound, and the less likely it is that those tissues will be smooth and flat. Dressings for these wounds are provided both 15 to protect the wound tissue and to absorb liquid exudate from the wound. Such a dressing may be a hydrocolloid dressing with a suitable reinforcement, such as a methylcellulose gel supported on a waterproof backing sheet. These dressings are generally made available as 20 flat sheets with the face of the dressing provided with an adhesive surround to an absorbent portion which is covered by a protective film that can be peeled off immediately before use.

A large wound with profuse exudate poses a number 25 of problems in the matter of dressings. A conventional dressing may quickly become saturated, and the edges of the dressing may not remain sealed to the patient's skin, especially if the flat dressing has to be curved in two directions, leading to pleating, and if the tissues 30 surrounding the wound are mobile. Multiple adjacent lesions exacerbate these problems. A raised wound is —

-t also liable to abrasion. Leakage from a saturated dressing can cause great discomfort and be extremely unpleasant, especially if the wound is, for example, an 35 odorous malignant cancer lesion. It can be seen that a patient with multiple wounds each requiring a change of dressing every two hours day and night has a very low quality of life.- Further, it may well be that the recovery of the patient, or resistance to further deterioration in the patient's condition, is prejudiced in these conditions. In addition, the demands in terms of time that the necessary changes of dressing make on nursing staff may mean that less time is available for other important nursing tasks; and indeed, the cost of the necessary dressings and staff time are also a drain on financial resources.

Furthermore, a patient with large and complex wounds may also desire prosthetic treatment in order to attain a more normal appearance. Prosthetic treatment is often hindered by the presence of bulky and/or irregularly shaped dressings covering wounds.

The present invention lies in any novel combination of features disclosed herein.

In accordance with one aspect of the invention, a dressing for a wound comprises a pliable and resilient containment member having an under surface and a top surface for surrounding and covering a wound, wherein the under surface matches the contours of the surrounds of the wound. In another aspect, the top surface matches the contours of a patient's body and thereby has a prosthetic effect. Additionally, the under surface may define a void for location immediately above the wound. The void may contain replaceable absorbent dressing material. Optionally, an aperture extends down from the top surface and communicates with the void to permit replacement of said absorbent material in the void therethrough.

While it would no doubt be possible to hold the pliable and resilient body to the wound by alternative means, it is considered almost invariably advantageous to provide a biologically acceptable adhesive between the under surface of the containment member and the surrounds of the wound. A- suitable adhesive not only holds the member against the surrounds of the wound but also seals between the member and the tissue surrounding the wound. The void over the wound area may be moulded into the containment member, especially for flat or raised wounds, but may not need to be so moulded in the case of dressings for deeply depressed wounds. In these cases there may be adequate space above the top surface of the wound tissue to leave a void for replaceable absorbent dressing material below the level of the patient's surrounding skin.

The optional aperture in the containment member may be left open over the wound, for easy access and to allow the wound exposure to air. Alternatively an openable cover may be provided over the void. The cover may be formed in the top surface of the member, by cutting a single slit or crossed slits in the material of the member to form an aperture which is normally closed by integral flaps that are separated by the slits, or may be formed as a separate removable plug for the aperture. The pliable and resilient^"containment member is of any suitable material that can be moulded to accurately take on the contours of the tissue surrounding the wound on its under surface and/or to take on the contours of a patient's body on its top surface. Preferred materials are absorbent, and include foams, which have the benefit of light weight. The most preferred foams are open celled, for maximum absorbency of wound exudates. As made, the foam may have a thin porous skin, which may act as a partial barrier to leakage. The foam may be provided on most of its outer surfaces with an impermeable outer skin, by applying a flexible outer layer. For example, a lacquer in the form of an acrylic emulsion such as that sold under the name Pros-aide, a prosthetic adhesive, will dry to form a flexible waterproof barrier on latex foam. Also, for example, a polyurethane film may be adhered to the foam using a suitable adhesive material. On the other hand, the thin skin on the interior surfaces of a foam containment member may be shaved to increase its surface porosity in the region of the void, where the dressings are to be contained. The invention extends to a dressing as aforesaid applied to a wound, including an absorbent dressing material contained in the void over the wound.

The invention further provides a method of making a wound dressing comprising taking a cast of a relevant body part and making a positive former therefrom; moulding the form of a dressing containment member with an under surface and a top surface, wherein at least one surface is matched to the contours of the body part on the former and optionally includes a void sufficient to contain replaceable absorbent dressing material for location immediately over the wound area; making a mould for reproducing the form of the containment member; and casting a pliable and resilient containment member from the mould; the method including the optional step of forming an aperture communicating between the void and the top surface of the containment member to permit replacement of said absorbent material in the void therethrough.

The method of the invention may also include the additional steps of applying the containment member to the surrounds of the wound with its moulded contours matched thereto; interposing a biologically acceptable adhesive between the containment member and the surrounds of the wound; and containing the dressing in the void of the said member. The invention is illustrated by way of example only in the accompanying drawings, in which:

Figure 1 shows a wound dressing applied to a patient's shoulder; Figure 2 shows a cross section through the dressing of Figure 1; and

Figure 3 shows in corresponding cross section a stage in the manufacturing process of the dressing. In Figures 1 and 2 a latex foam containment member 10 has a top surface 12 and an under surface 14 which is in exact conformity with the contours of the surrounds of wound 16. The under surface of the member is fixed to healthy skin surrounding the wound tissue by means of a medically acceptable non-allergenic adhesive 18. The member 10 is formed to have a void 20 immediately above and around the wound tissue, so that the member does not come into direct contact with the wound.

On the wound and within the void is a layer of absorbent wound dressing material 22, which is replaceable through aperture 23 in the top surface of the containment member. . The outer edges of the containment member where the top and under surface meet are feathered to blend smoothly into the surrounding skin areas. For improved cosmetic effect, the member 10 is also pigmented to match the skin.

In order to make the containment member 10, a direct impression is first taken of the wound and surrounding area of the patient's body. One suitable compound for this purpose is conventional dental alginate impression compound, which can typically be prepared by mixing the compound as supplied in powder form with water according to the manufacturer's instructions, and immediately applying it to the patient's body, where it will set to a flexible shell in a few minutes. The shell can the be reinforced, if necessary, by applying a plaster case to it, and after the plaster has set it is lifted off completely with the detailed alginate impression. A plaster positive is then made by casting directly from the original alginate impression. It is convenient to retain this positive as a master copy, and to make a plaster duplicate from it, for use as former in the next stage of the process. Figure 3 shows such a former 24, made with a flat base 26 for stability, and with locating lugs 28, outside the area designated for the eventual containment member, for establishing a proper register with a second mould half 30 when the former 24 is used as a first mould half at a later stage. A latex bleed passage 34 may be drilled in the former to release pressure during the subsequent casting steps.

A clay sculpture 32 to the desired shape of the containment member is next modelled on the former 24 around the wound area, having the necessary void 20 and aperture 23, and feathered outer edges to blend into the shape of the former. The outer surface of the clay sculpture may also be shaped to match the contours of a patient's body in order to achieve a prosthetic effect. Any suitable modelling clay may be used for this purpose. Next the second mould half 30 is cast in plaster over the clay and outward to register with the lugs 28 on the former.

When the second mould half is set, it is removed from the former 24, and the clay is washed from both mould surfaces. Any slight residual amount of clay may act as a mould release agent for the latex containment member.

A latex foam casting mixture is then made up. This may be based on thickened (eg creamed) and preserved (eg with ammonia) raw liquid latex, with additives that - 1 -

may include foaming agents (soaps and the like) , foam stabilisers, primary and secondary gelling agents, softeners or extenders (eg mineral oils or paraffin) , curing and vulcanising agents, and pigments. The mixture is beaten to the consistency of a stiff but fluid foam. The foam latex mixture is then loaded on to the former 24, and optionally on to the second mould half 30, which is then pressed into position on the former until the edges of the two mould halves meet. Excess pressure is relieved by the escape of foam through passage 34 in the second mould half.

The closed mould is set aside for eg 10 to 30 minutes for the latex to gel, then placed in an oven to cure the latex foam at 100°C for about 2 hours. After allowing to cool, the mould is removed from the oven and opened. The now pliable and resilient appliance is stripped from the mould, washed in water, squeegeed, and allowed to dry. At this stage the appliance may be impregnated with medicaments such as antibacterial agents or disinfectants, deodorants, and the like. It may also be sterilised and sealed in an aseptic container.

The containment member may now be used in a dressing as illustrated and described with reference to Figures 1 and 2. A suitable adhesive is Dow Corning 355 medical adhesive, which is 18.5% by weight dimethylpolysiloxane in trichlorotrifloroethane. The absorbent dressing materials that are used on the wound may be of any convenient kind, such as calcium alginate wafers, alginate wool, or a flat dressing cut into small strips.

The wound dressing of the invention as illustrated and described above has been found to show exceptional benefits, in improving patient comfort, assisting nursing care, and saving nursing time. The dressing 22 can be speedily replaced with relatively little disturbance to the patient, since they need only be packed into the void 20. A thick dressing for great absor-bency can be used. Excess exudate that is not absorbed can be absorbed by the latex foam containment. A complete change of dressing, that may previously have been required every two hours, may now be deferred for up to 24 hours, or even several days, with no spillage from the wound area. The need for repeated cleaning of the patient and the bedding may be considerably reduced. The tissue and atmosphere around the wound, which is partially enclosed by the member 10, and which may if desired be completely enclosed if the aperture 23 is provided with a closure, may be controlled as to exposure to air, and humidity. It may be possible to treat the wound by appropriate methods, such as ultraviolet light, without removing the whole dressing. The appliance may be made cosmetically acceptable, restoring body symmetry and giving the patient an appearance closer to normality. In particular, movement by the patient is accommodated by the pliable and resilient member 10 without abrasion of the wound, and the softness of the dressing is protective and tolerable in the wound area. It will be appreciated that use of the dressing extends to use as a prophylactic device. The dressing is also suitable for both the prevention and treatment of decubitus ulcers.

Claims

1. A dressing for a wound comprising a pliable and resilient containment member having an under surface and a top surface for surrounding and covering a wound wherein the under surface matches the contours of the surrounds of the wound.

2. A dressing for a wound comprising a pliable and resilient containment member having an under surface and a top surface for surrounding and covering a wound wherein the top surface matches the contours of a patient's body.

3. A dressing as claimed in Claim 1 or Claim 2 wherein the under surface defines a void for location immediately above the wound.

4. A dressing as claimed in Claim 3 wherein the void contains replaceable absorbent dressing material.

5. A dressing as claimed in Claim 3 or Claim 4 wherein an aperture extends down from the top surface and communicates with the void.

6. A dressing as claimed in Claim 5 wherein the aperture is provided with an openable cover.

7. A dressing as claimed in any one of the preceding claims wherein the containment member is made of an absorbent lightweight material.

8. A dressing as claimed in any one of the preceding claims wherein the top surface is provided with an impermeable and flexible outer layer.

9. A dressing as claimed in any one of the preceding claims wherein the under surface is coated with an adhesive for holding the containment member against the surrounds of the wound.

10. A method of making a wound dressing comprising taking a cast of a relevant body part and making a positive former therefrom; moulding the form of a dressing containment member with an under surface and a top surface wherein at least one surface is matched to the contours of the body part on the former; making a mould for reproducing the form of the containment member; and casting a pliable and resilient containment member from the mould.

11. " A method of making a.wound dressing as claimed in Claim 10 wherein the form of a dressing containment member is moulded to include a void in the under surface for location immediately over the wound.

12. A method of making a wound dressing as claimed in Claim 11 wherein the form of a dressing containment member is moulded to include an aperture extending down from the top surface and communicating with the void.