DRESSING

Abstract: A dressing with a pad (10) to be applied to a wound and consisting of a flexible, capillary-active material and stiffening elements. The stiffening elements extend at right angles to the flat side of the pad to be applied to the wound and are arranged to stabilise the volume of the pad (10) such that it can absorb a predeterminable amount of fluid, and to counteract and distribute forces acting on the pad (10). To form an occlusive dressing, the pad can be enclosed in a cover (11) of vapour-permeable, plastic film having a perforated portion (12) on the flat side of the pad facing the wound.

Description: DRESSING The present invention relates tc a dressing with a pad consisting of a flexible, capillary-active mate¬ rial to be applied to a wound. Dressings are used for treating e.g. surgical 5 wounds, open wounds and portions of the skin subjectec to pressure. Dressings ready for use are adapted to these applications and fulfil the following functions to a varying degree. 1. PROTECTION AND IMMOBILISATION 0 By avoiding pressure, shocks and ir.cr.ion n the tissue area, it is possible to prevent cr reduce tis¬ sue injury. The less the tissue injury is, the more efficient becomes infection control and healing. Pair. is relieved. 5 2. ISOLATION If the wound is clean, infection is prevented. If the wound is already infected, the infection is prevented from spreading to surrounding areas. Unne¬ cessary direct contact with the patient's body fluids should be avoided, which means that leakage c pus and blood from the dressing should be prevented as far as possible. The demand for isolation has become still more justified with the advent cf new sources c infection, such as AIDS. 5 3. PREVENTION OF EVAPORATION AND DEHYDRATION This is of importance in open wounds. Healing here takes place e.g. by ingrowth of the cells of the skin from the edge portions of the wound. These cells are especially sensitive to an unfavourable C. environment, and dehydration means that neal n will be considerably delayed. . ACTIVE INFLUENCE This can be achieved oy adding chemical E star.c. such as infection centre1 aσents cr ..=__::.: sunst~r.ee; or by removing bacteria and pus from the surface cf the wound and the dressing. For a better idea of the prior art, a brief ac¬ count of conventional ready-for-use dressincrs and 5 their major drawbacks will now be given. 1. DRESSINGS FOR SURGICAL WOUNDS A dressing of this type consists of a pad to be applied to a wound and disposed centrally on a thin backing layer of gauze or nonwoven material. 0 Around the pad, the backing layer is provided with adhesive for fixing the dressing to the skin surround¬ ing the wound. The pad generally consists cf a piece of absorbent felt. Superposed absorbent layers cf felt havinσ different densitv and riσiditv are some- meabie. In use, blood or pus is absorbed by the pad. If a dressing partially saturated with liquid is sub¬ jected to pressure, e.g. when the patient is lying or. the dressing or parts of the bandage located outside 0 are compressed, there is a reduction cf the volume cf the pad which is capable cf retaining liquid. The backing layer is soaked and the isolating a r seal against tne environment is broken, which means bet:. risk ef infection and practical inconveniences. An 5 unplanned change cf dressings may be necessitated. Thus, this type of dressing cannot be considered vo- iumetrically stable in the sense that a given volume cf blood or pus can always be retained in the dressing. 2. DRESSINGS FOR OPEN WOUNDS 0 Occlusive dressings used are in the form of a plastic film or adhesive plate. The dressing mate¬ rials are either completely occlusive or vapour- permeable to a varying degree. They are net permeable tc water. Evaporation cf clinical impertar.ee s cre- - ' - ^ente , like dehydration. Tne occlusive film consists ef a cieee ef adr.esive elastic colvrr.er f lm, aetl ec to the wound and the surrounding skin. The adhesive surface adheres to the skin whereas not to the wound, thus forming a watertight wound pocket which may con¬ tain wound exudate or pus. A considerable drawback is that such a pocket has no volume stability. If the liquid retained is subjected to pressure, the above-mentioned consequences are had. Further, the film affords no protection against pressure, shocks or motion. Active influence is not possible. The oc- elusion plate consists of a thin foam material having a coating of polymer film and provided on one side with a slightly thicker layer of adhesive. The adhe¬ sive forms together with the pus a low- iεccsity ge . This plate suffers from the same drawbacks as the occlusive film. Since there is no volumetrical y stable space, undesired leakage may take place under the conditions stated above. As opposed to the film, the plate provides a certain protection and immobilisation. Active influence on the wound is not possible. The flush dressing is a special type of occlusive dressing which also allows active influence on the wound. It consists of a wound pad which is in the form of a piece cf felt covered with polymer film. One cr mere central perforations are facing the wound, ctnerwis. the film is watertight. The surface of the film sur¬ rounding the perforations is adhesive and allows oc¬ clusive application to the skin surrounding the wound. The dressing has two connections which can be used simultaneously for supplying treatment liquid and for draining pus or wound exudate. The liquid supplied is distributed in the open capillary-active pore system of the pad. Drainage is effected by applying a nega¬ tive pressure which is also distributed n the pore system. A major drawback here is that the dressing s not volumetrical y stable and sc, leakage may occur (see above). Further, functional trouble may arise f tne catiliarv-aetive pore system, s occluded ey co eres ■ sion, which may also be caused by a negative pressure in the dressing. 3. PROTECTIVE DRESSING Protracted pressure may cause injury and g ve rise to wounds also in normal skin. The protective dressing relieves a portion of the skin subjected to pressure and is used in the prophylaxis of pressure-induced wounds, primarily in bedridden, immobilised patients. The occlu¬ sion plate is now being used for this application. Since the plate is thin and has no reinforcement, only insuf¬ ficient relief is obtained. The object of the present invention is to over¬ come the drawbacks inherent in prior art dressings, by providing a dressing which can be used as an ordi- nary dressing and as occlusive dressing, fiusn dress¬ ing, dressing for surgical wounds as well as protective dressing, and which by dimensional stabilisation can absorb a predetermined amount of fluid from a wound and efficiently protects the wound from stresses. This object is achieved in that the dressing has elements of a given rigidity and length orthogonally tc the fiat side of the pad to be applied to the wound, said elements being adapted both to stabilise tne volume cf the pad so as to give it a predeterminael liqu d- absorbing volume, and to counteract and distr oute the forces directed against the pad. The invention will now be described in more detail hereinbelow with reference to the accompanying drawing schematically showing an embodiment of an occlusive dressing. Fig. 1 is a bottom plan view cf a dressing according to the invention. Fig. 2 is a section taker, along the line II-II in Fig. 1. Fig. 3 shows an edge portion of the dressing in vertical position. Figs. 4, 5 and 6 illustrate specific embodiments ef t e dressing. The dressing according to the invention consists of a pad 10 to be applied tc a wound and consisting ef caei arv-aetive material, i.e. a mater . v ; n e:. is able to absorb fluids from a wound when the pad is applied to it. This material may be woven or non- woven or consist of a foam material open cells and being of a nature to minimise adhesion to the wound. The capillary-active material 10 is enclosed in a cover of plastic sheeting or film 11 which covers the top side of the pad and extends as a single piece therefrom around the edges of the pad so as also to cover the bottom side of the pad 10. In the part of the sheeting which covers the bottom side of the pad, there is provided a perforated portion 12 the boundary edges of which are spaced from the edges of the pad so as to form a non-perforated frame of sheeting 13 coated with a suitable adhesive, such as acrylic glue or cellulose synthetic rubber glue adhering to and absorbing moisture from the skin. The film or sheet¬ ing 11 is liquidtight, but preferably vapour-permeable and may be translucent. Instead of a film or sheeting 11 of plastic material, it is possible to use a film or sheeting of other materials, such as natural or synthetic rubber. The essential thing is that the film or sheeting is liquidtight and has the desired airtightness. The pad 10 is preferably tapering toward, its edges, as indicated in Fig. 2. The pad 10 has stiffening elements which extend between the opposite flat sides of the pad and which may be of different types. In the embodiment shown in Fig. 2, the stiffening elements consist of walls 14 extending between the opposite flat sides of the pad. In Fig. 2, the walls 14 extend between the oppo¬ site long sides of the dressing, but they may also extend between the short sides or between both the short sides and the long sides, so as tc form a grat¬ ing. The walls 14 can be obtained in different ways. Thus, for example, the pad may first be manufactured with the walls 14, whereupon the space between the walls is filled with caeiilarv-activε material. It is also conceivable to manufacture the pad 10 in one working operation by also making the walls 14 from the capillary-active material, however giving them in a suitable manner during the manufacturing process a higher density than the intermediate material so that they become more rigid than this latter material. If the capillary-active material consists of thermoplas¬ tic, it is possible, by means suitably shaped, to pro¬ vide e.g. -tubular or hourglass-shaped formations orient- ed with their longitudinal direction at right angles tc the flat sides of the pad 10 and having a wall cf in¬ creased rigidity, counteracting and distributing the forces exerted on the outer side of the dressing. The stiffening walls 14 may also form an oblique angle or a latticework with the perforated portion 12. According to Fig. 4, the layer of stiffening ele¬ ments need not extend between the flat sides cf the pad, but may consist of a thinner layer of elements IT which, as shown in the Figure, may be disposed central- ly in the pad and have capillary-active material between it and the flat sides of the pad, but which may also be located adjacent e.g. the outwardly facing side tnerecf , with capillary-active material filling tne space between tne layer of stiffening elements and tne inwardly facing side of the pad. Instead of the above-mentioned formations, the pad may be provided with cushions 18 extending be¬ twee the opposite flat side surfaces of the pad. These cushions 18 may be made from a sheeting mate- rial and be filled with air or elastic material. The stiffening elements need not necessarily oe provided in the pad, but may instead be connected tc the sheeting, which may be achieved e.g. by embossing the sneering in a suitable manner. For ic nmg tne sneering 11 to the pad, the elements are tressed owr mtc the pad, yielding an arrangement which resemble." —*-τ_-^ πc *" ~- -"• ~~ ~ ~ ~~ -* In certain applications, it may be suitable to use a thicker and optionally also reinforced sheeting 19 on one or both of the opposite flat sides of the pad. Such a stronger sheeting is suitably used when the dressing may be expected to be subjected to substantial stress. Instead of a sheeting, it is possible to use a foam ma¬ terial with closed cells. Although the volume of fluid which can thus be taken up by the pad is limited by the existing volume of air, the capillary-active component makes it possible for the pad to take up even more fluid. When, in the use cf the dressing, fluid is taken up in the pad, an excess pres¬ sure is produced therein, which is however equalised if the sheeting is vapour-permeable. Thanks to the arrange- ment of stiffening means, it is possible to accurately determine the amount of fluid that can be absorbed, and the dressing is chosen according to the nature cf the wound. Thus, if considerable amounts of fluid are expect¬ ed, a dressing with an extra thick pad is chosen. As pointed out above, the stiffening elements 14, IT and 18 also ensure that the wound is protected against stress, such as shocks, to which the dressing may unintentional¬ ly be subjected. A further advantage cf the dressing is that the absorbed fluid is collected m the pocket 16 formed by folding the sheeting around the edges of the pad, as shown in Fig. 3. Thus, the fluid will net tend to leak out between the sheeting and the underlying skin 15 if the dressing is oriented as shown in Fig. 3. To protect the wound and distribute the forces exerted on the dressing, the stiffening elements may be joined to each other in their ends ad acent the wound, by means of intermediate arms or formations which between them and the ends cf the elements define liquid-permeable .capillary' openings. The dressing according to the invention is useful for both open wounds and surgical wounds. The pad may be imoreαnatec with nealing agents, and tne dressing may also be provided with inlets and/or outlets, pre¬ ferably both, for circulation of treatment liquid (flush dressings), as described in Swedish Patent 8008971-9. Moreover, the dressing can be used as a protective dressing of the design shown in Fig. 1, but in such a case the perforated portion preferably consists of a plurality of micropores in the area which in Fig. 1 is occupied by the single, large hole in the sheeting 11. The pad may have hydrophobic or hydrophilic pro¬ perties, optionally alternating in different layers. The surface may be heparinised or provided with a bactericide.

Claims: CLAIMS 1. A dressing with a pad (10) consisting of a flex¬ ible capillary-active material to be applied to a wound, c h a r a c t e r i s e d in that it has elements of a given rigidity and length orthogonally to the flat side of the pad to be applied to the wound, said elements being adapted both to stabilise the volume of the pad so as to give it a predeterminable liquid-absorbing volume, and to counteract and distribute the forces directed against the pad. 2. Dressing as claimed in claim 1, c h a r a c ¬ t e r i s e d in that the elements are connected to each other in their ends facing the wound, by means of arms or formations extending parallel to the flat side of the pad to be applied to the wound, liquid- permeable openings being defined between said arms or formations and said element ends. 3. Dressing as claimed in claim 1 or 2 , c h a ¬ r a c t e r i s e d in that the opposite flat sides of the pad are coated with a sheeting (11) or film of plastic or the like, said sheeting having en the flat side facing the wound a perforated portion to be applied against the wound and, provided around said perforated portion, a coating adhesive to the skin, and said sheet¬ ing extending as a single piece from the flat side of the pad facing away from the wound, around all edges (20) of the pad and a predetermined distance from said edges to said perforated portion (12). 4. Dressing as claimed in claim 1, 2 or 3, c h a ¬ r a c t e r i s e d in that the stiffening elements (14, 17, 18) are integrally formed with the pad (10) and con¬ sist of formations therein having increased compressive strength. 5. Dressing as claimed in claim 1, 2 cr 3, c h ¬ r a c t e r i s e d in that the stiffening elements consist of generally hourglass-shaped cells in the pad (10). 6. Dressing as claimed in any one of claims 1-4, c h a r a c t e r i s e d in that the stiffening ele- ments (14) consist of walls extending between the oppo¬ site flat sides of the pad (10). 7. Dressing as claimed in any one of claims 1-5, c h a r a c t e r i s e d in that the stiffening ele¬ ments (17) are arranged in a separate layer between the flat sides of the pad and that a capillary-active material is arranged between this layer and one or both flat sides of the pad (10). 8. Dressing as claimed in claim 1 or 2, c h a ¬ r a c t e r i s e d in that the stiffening elements (18) consist of cushions having a plastic cover and containing air or elastic material. 9. Dressing as claimed in claim 1, 2 or 3, c h a ¬ r a c t e r i s e d in that the stiffening elements (17) are integrally formed with the sheeting (11), for instance as embossments, and extend into the pad (10). 10. Dressing as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the perfo¬ rated portion (12) consists of a single, large hole. 11. Dressing as claimed in any one of claims i-T, c h a r a c t e r i s e d in that the perforated por¬ tion (12) has a large number of holes. 12. Dressing as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the thickness of the pad (10) decreases towards the pad edges (20). 13. Dressing as claimed in any one of claims 3-12, c h a r a c t e r i s e d in that liquid inlets and/or liquid outlets are arranged in the sheeting or film on the side of the pad facing away from the wound or on the edge sides of the pad.

Inventors: KILEBY LARS-ERIK, SVEDMAN PAAL, KILEBY, LARS-ERIK, SVEDMAN, PAAL
Applicants: MOELNLYCKE AB, SVEDMAN PAAL, SVEDMAN, PAAL
Application year: 1988
Main classification: A61F13
IPC codes: A61F13