Wound dressing
The absorbent pad with embossed surfaces and recesses addresses the challenge of adhering to and absorbing fluids from uneven body parts, ensuring effective wound care and comfort.
Patent Information
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- ESSITY HYGIENE & HEALTH AB
- Filing Date
- 2023-12-31
- Publication Date
- 2026-07-23
AI Technical Summary
Existing wound dressings struggle to effectively adhere to and absorb fluids from uneven body parts, particularly those with joints or protruding bone structures, while maintaining comfort and flexibility.
An absorbent pad with a base shape comprising four leaf portions and a centre portion, featuring embossed surfaces and recesses, which enhances adaptability to complex body surfaces and improves fluid absorption.
The embossed absorbent pad provides enhanced fit and absorption on uneven body parts, supporting wound healing by retaining nutrients and promoting wound cleaning, while maintaining comfort and flexibility.
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Abstract
Description
This problem is solved by the present invention as described in the appended claims. In a first aspect, the invention relates to an absorbent pad for a wound dressing, wherein the absorbent pad has a base shape comprising four leaf portions surrounding a centre portion. The absorbent pad has a (wound-facing) proximal surface and a distal surface and one or more of the (wound-facing) proximal side and the distal side are embossed. In conjunction with the softened, embossed material, the four leaf-shape of the absorbent pad leads to a particularly soft and adaptable pad that is well suited for the treatment of the aforementioned uneven body parts, in particular body parts associated with joints or protruding bone structures, such as the elbow, knee, shoulder or heel. The absorbent pad is adapted to take up and retain fluids, such as wound fluids (exudate). The term “wound fluids” or “exudate” refers to fluids which have escaped from a wound, in particular because of inflammatory processes of the blood plasma. The wound fluids or exudates serve to supply the wound bed and the healing processes which are taking place there with a wide array of components, including nutrients for fibroblasts and epithelial cells, growth factors and cytokines. The wound fluids also assist in the cleaning of the wound and the degradation of damaged tissue. The absorbent pad has a distal surface and a proximal surface. The words “proximal” and “distal” are used herein to refer to the position of the respective surface in relation to the wearer when the wound dressing is worn. In line with the standard meaning of the terms in the art, “distal” refers to the surface which is farther away from the wearer and “proximal” refers to the surface which is closer to the wearer, i.e. closer to the wound, skin and / or other body surface. The proximal surface is, thus, the wound-facing surface of the pad, when the pad is used on a wound. The absorbent pad is a flat layer that usually comprises a woven or non-woven fabric to stabilise the absorbent materials structurally and / or functionally support the absorbent materials comprised in the pad. Non-woven materials are fabric-like materials made from short and / or long fibres bonded together by chemical, mechanical, heat or solvent treatment. The non-woven can e.g. be manufactured by milling the fibres. Exemplary nonwoven fabrics include airlaid fabrics, which are non-woven materials made of cellulose and polyolefin fibers. The absorbent material(s) may be embedded in the flat layer, e.g. in the woven or nonwoven material. The absorbent materials may e.g. be superabsorbent materials, such as one or more superabsorbent materials selected from the group consisting of superabsorbent fibers and superabsorbent particles. In one embodiment, the absorbent core is an airlaid mat - containing e.g. a cellulose non-woven - with embedded superabsorbent particles. The absorbent pad has a base shape comprising four leaf portions surrounding a centre portion. The base shape is the shape of the absorbent pad that is visible when viewed from a distal or proximal position (in relation to the flat-lying absorbent pad, e.g. when laid out on a table). The centre portion connects the four leaf portions with each other. It, thus, forms the centre (i.e. is in the middle) of the absorbent pad when viewed from a distal or proximal position. The leaf portions, thus, do not touch each other in the flat-lying absorbent pad. The leaf portions have a leaf- or fan-like shape when viewed from a distal or proximal position, i.e. they are narrower where they are connected to the centre portion and broader at their radially outer ends. Thus, each leaf portion has roughly the shape of a ginko leaf or a fan. The radially outer ends of the leaf portions (i.e. the ends most distanced from the centre portion) can have the shape of a semi-circle (when viewed from a distal or proximal position). For example, if the absorbent pad has four leaf portions, each leaf portion can have the shape of a semi-circle of about 30° or more on its outer end. It is preferred that all leaf portions of the dressing have the same or a similar shape and / or size. In one embodiment, the four leaf portions of the dressing have the same shape and size. The absorbent pad can have 4 leaf portions or more, such as, for example, 4, 5, 6, 7 or 8. An absorbent pad consisting of a centre portion and 4 leaf portions is a preferred embodiment. Each leaf portion is circumferentially separated from the adjacent leaf portion by a recess. Accordingly, the number of recesses and leaf portions in the absorbent pads will usually be the same (e.g. 4 leaf portions, and 4 recesses, arranged around a centre portion). A “recess” is a gap in the absorbent pad or, in other words, a more or less V- or U-shaped material removal in the absorbent pad. The recess is curved inwards, i.e. towards the centre portion. The below properties defined for a recess preferably apply to all recesses of the absorbent pad, i.e. each recess of the absorbent pad. For example, the below properties can apply to all four recesses of an absorbent pad having four recesses and four leaf portions. Each recess has a first radial side and a second radial side. Together, these form the sides of the recess that separate the recess from the adjacent leaf portions. In other words, the radial sides of a recess are also radial sides of adjacent leaf portions. It will be understood that the description of the sides as “radial” means that these sides extend from the direction of the centre portion approximately into the direction of an outer end of the absorbent pad. Thereby, the radial side does not necessarily follow the strict direction of a radius, but can deviate slightly from the radius, e.g. by 20° or less, 15° or less, or 10° or less. In other words, the longitudinal axes extending along the radial sides of the recess may be slightly tilted with respect to a radius extending from the centre portion. Moreover, the radially inner and / or outer ends of the radial sides may be rounded. Such rounded ends provide for a better adaptability of the absorbent pad to the skin or wound surface of the wearer. The recess further, has a central side which is the boundary between the recess and the centre portion of the absorbent pad. This central side can be rounded. In preferred embodiments, the longitudinal axis (A) of the first radial side and the longitudinal axis (B) of the second radial side of a recess intersect outside of the area of the absorbent pad (compare Fig. 4B), i.e. outside of the surface of the absorbent pad. The longitudinal axis of a radial side is the longitudinal axis extending along said side. In certain embodiments, the longitudinal axis (A) and the longitudinal axis (B) can intersect on the side of the centre portion that is averted from the respective recess (see Fig. 4B). Thereby, the recess has a relatively constant width with a broad end close to the centre portion. The intersection is outside of the area of the absorbent pad, i.e. the area where material of the absorbent pad is located. The intersection may be within a recess, such as the recess on the opposite side of the centre portion, or outside of the area of the absorbent pad and its recesses. In other words, the width of the recess varies only slightly along the length of the recess, for example by 30% or less, or 20% less, or 10% or less, between two measuring positions within the recess that are located at 20% and 80% of its length. In other words, the width of the recess varies e.g. from 0% to 30%, from 0% to 20%, or from 0% to 10%, between two measuring positions within the recess that are located at 20% and 80% of its length (wherein the length is measured from the centre portion of the absorbent pad in the direction of the outer edge of the absorbent pad and its width is measured in circumferential direction, i.e. between one recess and the next). It has been found that this shape of the recess optimizes the efficiency of production of the embossed absorbent pad because it improves the processability after cutting the absorbent pad from an absorbent sheet considerably. The precisely cut absorbent pad separates more easily from a cutting tool. Additionally, the relatively constant width of the recesses provides for leaf portions which are relatively broad at their outermost edges and, thus, provide for a good connection to the skin regions adjacent to a wound. A first and a third of the leaf portions can be arranged axisymmetrically in relation to one another. Additionally or alternatively, a second and a fourth of the leaf portions are arranged axisymmetrically in relation to one another. The first, second, third and fourth leaf portion are arranged around the centre portion in the order of their numbering, e.g. in clockwise direction. The axial symmetry may be a mirror symmetry. The central axes (Y) of the leaf portions can be circumferentially distanced 90° from one another, preferably in an absorbent pad with four leaf portions. This provides for a particularly symmetric arrangement. The 90° refers to a circle having the centre portion in its middle when viewed in the flat-lying absorbent pad from a proximal or distal position. The centre portion has a roughly similar width as the length of each of the leaf portions. For example, the centre portion can have a width that is from 0.5 to 2 times of the length of the leaf portions. The “length” of the leaf portion extends from the centre portion to the outer circumference of the absorbent pad, e.g. along the central axis of the leaf portion. The centre portion can e.g. have a width of from 1 cm to 10 cm, preferably from 1 to 5 cm. The length of the leaf portions at the central axis of the respective leaf portion can e.g. be from 1.5 cm to 15 cm, preferably from 1.5 cm to 8 cm. A central axis is also known in the art as “middle axis” or “center axis”. These terms can, hence, be used synonymously. The absorbent pad comprises a wound facing proximal surface and a distal surface. One or more of the wound facing proximal surface and the distal surface are embossed. In other words, both or only one of the surfaces can be embossed. The embossing softens the structure of the absorbent pad so that it is easier adaptable to complicated forms, such as body parts with underlying bony structures. In this regard, the embossing and the aforementioned shape of the recesses act synergistically towards an improved fit to complicated body surfaces. Moreover, the shape of the recess makes the production of the softer absorbent pad easier as described above. The embossing consists of a plurality of indentations in the wound facing proximal surface and / or the distal surface. These indentations can have a round shape or any other suitable shape known in the art, such as a square shape. Each indentation preferably has a diameter of from 0.2 to 5 mm, or 0.2 to 3 mm. As explained in more detail elsewhere herein, the thickness of the absorbent pad is from 0.5 to 5 mm, preferably from 1 to 4 mm, e.g. from 1.5 to 3 mm. In accordance with the present invention, the pad is to be understood to have a continuous extension in one plane (x and y direction) and a thickness perpendicular to said plane (z direction), which thickness is typically less than the x-y-extension, preferably at least by a factor of 10. It will be understood that the thickness is measured in a spot without embossing, i.e. without an indentation. As outlined above, the absorbent pad can e.g. comprise superabsorbent particles and / or superabsorbent fibres. Therefore, in a second aspect, the invention relates to superabsorbent particles or superabsorbent fibres arranged in an absorbent pad of the invention for use in the treatment of a wound at a heel, knee, elbow, or shoulder. The absorbent pad is suitable for use alone or in a wound dressing with further components. Hence, in a third aspect, the invention relates to a wound dressing comprising or consisting of (a) a sheath; and (b) an absorbent pad of the invention within the sheath. The sheath comprises a proximal sheath layer on the proximal side of the absorbent pad and a distal sheath layer on the distal side of the absorbent pad. The sheath is a closed body enveloping an inner sheath space. Within that inner sheath space, the absorbent pad is arranged. The inner sheath space is surrounded completely by the proximal and distal sheath layers. The sheath may be closed by sealing the outer edges of the proximal and distal layers of the sheath. In addition to the sheath and the absorbent pad, the wound dressing may comprise a covering layer. Specifically, the wound dressing may comprise (a) a covering layer; and (b) the sheath on the wound facing side of the covering layer. The covering layer is, thus, located on the distal side of the sheath and, thus, farthest away from the wound and skin surface when the wound dressing is worn. The cohesion between the covering layer and the other layers of the dressing can be ensured by adhesive or lamination. The covering layer can be highly flexible to allow for an increase in volume of the absorbent pad and, consequently, the sheath. The covering layer can be stretched and, for this purpose, comprises a stretchable material. The covering layer can e.g. consist of or comprise a material selected from the group consisting of polyurethane and co-polyester. The covering layer can be liquid-impermeable. The sheath material is preferably liquid-permeable. The proximal sheath layer and / or the distal sheath layer can e.g. comprise or consist of a woven or non-woven material, wherein the latter is preferred. The non-woven can e.g. consist of or comprise of a material selected from the group consisting of polypropylene, polyester, co-polyester and combinations thereof. In certain preferred embodiments, the sheath is a non-woven polypropylene material. The non-woven material can be airlaid. The material can have a spun-bound or filament-laid structure. The sheath can have a circular shape. Alternatively, the sheath can have an outer shape that corresponds to the outer shape of the absorbent pad. The sheath is sufficiently large to allow for an expansion of the absorbent pad. The sheath encloses an inner sheath space that has an inner sheath area adapted to extend parallel to the wound surface within the flat-lying and unwetted wound dressing. The absorbent pad has a proximal surface area adapted to extend parallel to the wound surface within the flat-lying and unwetted wound dressing. The size of the proximal surface area of the absorbent pad is from 40% to 90% of the size of the inner sheath area. The proximal surface area of the absorbent pad can e.g. be from 50% to 80% of the size of the inner sheath area. For example, the proximal surface area of the absorbent pad can be from 1 500 mm2 to 60 000 mm2 and the inner sheath area from 2 400 mm2 to 70 000 mm2. In another aspect, the invention relates to a method for producing an absorbent pad according to the invention, comprising steps of a) embossing an absorbent sheet; b) cutting an absorbent pad according to the invention from the absorbent sheet; and c) optionally, enveloping the absorbent pad in a sheath. Embossing in step a) is used to change the shape of the absorbent sheet from a flat sheet to a shaped sheet, so that there are areas in the sheet that are raised and / or recessed from the rest of the surface. The embossing therefore constitutes a deformation of the previously flat sheet and results in an absorbent sheet having a particular relief. The embossing can be carried out between an embossing roll and a counter roll. The embossing roll can have protrusions on its circumferential surface leading to embossed depressions in the absorbent sheet. Counter rolls may be softer than the corresponding embossing roll and may consist of rubber, such as natural rubber, or plastic materials, paper or steel. By embossing, a pattern can be applied to the absorbent sheet fulfilling a decorative as well as the functional purpose of softening the absorbent sheet. The embossing improves the softness of the absorbent sheet. Cutting an absorbent pad according to the invention from the absorbent sheet according to step b) may be carried out with a punching tool that has the desired shape and size. Cutting may, thus, be by punching. As described above, the relatively straight form of the recesses makes sure that the punched absorbent pads separate easily from the punching tool. Finally, in a step c), the absorbent pad may be enveloped in a sheath as described above. For this purpose, the proximal and distal sheath layers may be assembled around the absorbent pad in the order proximal sheath layer - absorbent pad - distal sheath layer and the two sheath layers may be connected at their outer edges. Connection may be by ultrasonic sealing or other means of adhesion. Preferably, the connection between the two sheath layers creates a closed space without openings. The absorbent pad does not need to adhere to the two sheath layers. It can remain unadhered within the sheath. This way the absorbent pad can move slightly within the sheath, further contributing to the good fit of the wound dressing to the wound and skin surface. BRIEF DESCRIPTION OF FIGURES Exemplary embodiments of the invention are shown schematically in the drawings. Fig. 1a schematically shows a known absorbent pad without embossing; Fig. 1b schematically shows an absorbent pad of the invention, wherein the absorbent material is embossed and the recesses have a particular shape; Fig. 2 schematically shows a wound dressing of the invention comprising a sheath and an absorbent pad enclosed therein; Fig. 3 schematically shows a cut through the wound dressing of Fig. 2; and Figs. 4a and b schematically show the shapes of the absorbent pads of Figs. 1a and 1b, respectively, wherein the longitudinal axes of the radial sides of a recess and the central axis of a leaf portion are depicted. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. DESCRIPTION OF EMBODIMENTS Additional advantages, characteristics, and features of the present invention will become clear from the following detailed description of exemplary embodiments with reference to the attached drawings. However, the invention is not restricted to these exemplary embodiments. Fig. 1a schematically shows a known absorbent pad 10. The absorbent pad 10 contains four leaf portions 14 that are arranged around a centre portion 16. The absorbent pad 10 consists of an absorbent material and is not embossed. Fig. 1b schematically shows an absorbent pad 10 of the invention. The absorbent pad 10 consists of a polypropylene non-woven fabric containing > 40% superabsorbent particles 42. One side of the absorbent pad 10 contains an embossing. The embossed side may either be used as the wound-facing proximal surface 18 of the absorbent pad 10 or as the distal surface 20 of the absorbent pad 10. Overall, the embossing improves the softness of the absorbent pad 10. The embossing consists of a multitude of regularly arranged indentations 28 within the surface of the absorbent pad 10. The absorbent pad 10 contains four leaf portions 14 and four corresponding recesses 22 that are arranged between the leaf portions 14. The leaf portions 14 are connected through a centre portion 16 that is arranged in the middle of the absorbent pad 10 between the leaf portions 14. The recesses 22 each have a first radial side 24 and a second radial side 26. The first and second radial sides 24, 26 constitute the borders between the respective recess 22 and the respective adjacent leaf portions 14. Fig. 2 schematically shows a wound dressing 12 of the invention comprising a sheath 30 and an absorbent pad 10 enclosed therein. The absorbent pad 10 is the above-explained absorbent pad of Fig. 1b. The absorbent pad 10 is enclosed in the sheath 30 and it can be seen that the inner sheath area 40 is larger than the surface of the absorbent pad 10. Thereby, the absorbent pad 10 has sufficient expansion room to allow the superabsorbent particles to take up the wound exudate and swell. The sheath 30 is closed by ultrasonic sealing. The width of the sealed area is indicated by the two circles in Fig. 2. It can be seen that there is a distance between the inner edge of the sealed area and the outer edges of the absorbent pad 10. The diameter of the inner sheath area 40 can, thus, be larger than the maximal width of the absorbent pad 10, for example 0.5 cm or more, 0.75 cm or more, 1 cm or more. In other words, the diameter of the inner sheath area 40 can be larger than the maximal width of the absorbent pad 10, by e.g. from 0.5 to 3 cm, from 0.75 cm to 3 cm, or from 1 cm to 3 cm. Fig. 3 schematically shows a cut through the wound dressing 12 of Fig. 2. It can be seen that the absorbent pad 10 is located within the sheath 30 formed by the distal sheath layer 34 and the proximal sheath layer 32. The proximal sheath layer 32 and the distal sheath layer 34 are both liquid permeable so that the sheath 30 allows wound exudate to be taken up by the absorbent pad 10. For this purpose, the absorbent pad 10 comprises superabsorbent particles 42 that can swell considerably and take up wound exudate. The absorbent pad 10 is not connected to the sheath 30, so that it can move if necessary within the inner sheath space 38. The proximal surface 18 of the absorbent pad 10 faces the proximal sheath layer 32. The distal surface 20 of the absorbent pad 10 faces the distal sheath layer 34. The proximal sheath layer 32 can be the wound-facing side of the wound dressing 12. Figs. 4a and b schematically show the shapes of the absorbent pads 10 of Figs. 1 a and 1 b, respectively, wherein the longitudinal axes A, B of the radial sides 24, 26 of a recess 22 2023477922 28 Jun 2026 and the central axis Y of a leaf portion are depicted. The embossing of the absorbent pad 10 of Figs. 1b and 4b is not shown in Fig. 4b to allow a clearer view of the axes. The central axis Y of a leaf portion 14 crosses said leaf portion 14 in its middle. It extends from the direction of the centre portion 16 radially to the outer edge of the leaf portion 14. 5 As the absorbent pad 14 of the embodiment shown has four symmetrically arranged leaf portions 14, the central axes Y of two opposing leaf portions 14 coincide. The central axes Y of the four symmetrically arranged leaf portions 14 are circumferentially distanced from each other by 90°. The recesses 22 of the absorbent pad 10 shown in Fig. 4a have a V-shape with a narrow 10 inner end and a broad outer end. Accordingly, the longitudinal axis A of the first radial side 24 and the longitudinal axis B of the second radial side 26 in this absorbent pad intersect approximately in the middle of the absorbent pad 10. In contrast, the recesses 22 of the absorbent pad 10 shown in Fig. 4b have a U-shape or broader V-shape with a broad inner and outer end. Accordingly, the longitudinal axis A of 15 the first radial side 24 and the longitudinal axis B of the second radial side 26 in this absorbent pad 10 intersect outside of the area (surface) of the absorbent pad 10, in particular in the area of the opposing recess 22. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general 20 knowledge in the art, in Australia or any other country. REFERENCE SIGNS LIST absorbent pad wound dressing leaf portion centre portion proximal surface distal surface recess first radial side second radial side indentation sheath proximal sheath layer distal sheath layer inner sheath space inner sheath area superabsorbent particles longitudinal axis of the first radial side longitudinal axis of the second radial side central axis of leaf portion
Claims
1. An absorbent pad for a wound dressing, wherein the absorbent pad has a base shape comprising four leaf portions surrounding a centre portion, and wherein the absorbent pad has a proximal surface and a distal surface and one or more of the proximal surface and the distal surface are embossed.
2. The absorbent pad according to claim 1, wherein each leaf portion is separated from the adjacent leaf portion by a recess, each recess having a first radial side and a second radial side, wherein the longitudinal axis of the first radial side and the longitudinal axis of the second radial side intersect outside of the area of the absorbent pad.
3. The absorbent pad according to any of claims 1 to 2, wherein a first and a third of the leaf portions are arranged axisymmetric in relation to one another and / or wherein a second and a fourth of the leaf portions are arranged axisymmetric in relation to one another.
4. The absorbent pad according to any one of the preceding claims, wherein the leaf portions have central axes that are circumferentially distanced 90° from one another.
5. The absorbent pad according to any one of the preceding claims, wherein the centre portion has a width that is from 0.5 to 2 times of the length of the leaf portions.
6. The absorbent pad according to any one of the preceding claims, wherein the centre portion has a width of from 1 cm to 10 cm, optionally from 1 to 5 cm.
7. The absorbent pad according to any one of the preceding claims, wherein the length of the leaf portions at the central axis of the respective leaf portion is from 1.5 cm to 15 cm, optionally from 1.5 cm to 8 cm.
8. The absorbent pad according to any one of the preceding claims, wherein the embossing consists of a plurality of indentations in the wound facing proximal side and / or the distal side, wherein an indentation optionally has a diameter of from 0.5 to 5 mm.2023477922 28 Jun 20269. The absorbent pad according to any one of the preceding claims, wherein the thickness of the absorbent pad is from 0.5 to 5 mm.
10. The absorbent pad according to any one of the preceding claims, wherein superabsorbent particles or superabsorbent fibres are embedded in the absorbent pad.
11. Wound dressing comprising or consisting of(a) a sheath; and(b) an absorbent pad according to any one of claims 1 to 10 within the sheath, wherein the sheath comprises a proximal sheath layer on the proximal side of the absorbent pad and a distal sheath layer on the distal side of the absorbent pad.
12. Wound dressing according to claim 11, comprising(a) a covering layer; and(b) the sheath on the wound facing side of the covering layer.
13. Wound dressing according to any one of claims 11 to 12, wherein the proximal sheath layer and / or the distal sheath layer comprise or consist of a non-woven material.
14. Wound dressing according to any one of claims 11 to 13, wherein the sheath has a circular shape.
15. Wound dressing according to any one of claims 11 to 14, wherein the sheath encloses an inner sheath space that has an inner sheath area adapted to extend parallel to the wound surface within the flat-lying and unwetted wound dressing; the absorbent pad has a proximal surface area adapted to extend parallel to the wound surface within the flat-lying and unwetted wound dressing; and the size of the proximal surface area of the absorbent pad is from 40% to 90% of the size of the inner sheath area.
16. Wound dressing according to claim 15, wherein the proximal surface area of the absorbent pad is from 50% to 80% of the size of the inner sheath area.2023477922 28 Jun 202617. Wound dressing according to any one of claims 15 or 16, wherein the proximal surface area of the absorbent pad is from 1 500 mm2 to 60 000 mm2 and the inner sheath area is from 2 400 mm2 to 70 000 mm2.
18. Method for producing an absorbent pad according to any one of claims 1 to 10, comprising steps ofa) embossing an absorbent sheet;b) cutting an absorbent pad according to any of claims 1 to 9 from the absorbent sheet; andc) optionally, enveloping the absorbent pad in a sheath.