Wound dressing

Abstract

The present disclosure relates generally to a wound dressing (100) comprising a backing layer (101), an adhesive skin contact layer (102) and a wound pad (103) arranged between the backing layer (101) and the adhesive skin contact layer (102), where the backing layer (101) and the adhesive skin contact layer (102) are arranged to extend beyond a contour of the wound pad (103) to form a boundary portion (104), where the wound pad (103) comprises an upper portion (103a) and a lower portion (103b); the upper portion (103a) is arranged in contact with the backing layer (101), where the surface area of the upper portion (103a) is smaller than the surface area of the lower portion (103b), and where the upper portion (103a) has a higher liquid diffusivity than the lower portion (103b).

Description

Technical Field

[0001] This disclosure generally relates to a wound dressing comprising a backing layer, an adhesive skin contact layer, and a wound pad disposed between the backing layer and the adhesive skin contact layer, wherein the backing layer and the adhesive skin contact layer are arranged to extend beyond the contour of the wound pad to form a boundary portion. Background Technology

[0002] The production of wound exudate is a natural part of the wound healing process. However, excessive production of wound exudate can be an indicator of wound infection and is often associated with chronic wounds.

[0003] Absorbent wound dressings are frequently used to treat various types of exudative wounds. In recent years, the design and construction of absorbent wound dressings have been improved to enhance their overall exudate handling capabilities.

[0004] Absorbent wound dressings can include multiple layers and a variety of materials, and are optimized for handling large amounts of wound exudate.

[0005] Advances in wound dressing design are often associated with increased costs. In this regard, the duration of wear is important. Wound dressings should preferably remain on the patient's skin and / or wound for an extended period to avoid unnecessary dressing changes and associated costs.

[0006] One challenge with absorbable wound dressings is that caregivers (and patients) often find it difficult to know when a dressing has reached its full capacity and needs to be replaced with a new one.

[0007] Often, wound dressings are changed and discarded too early, before they have reached their full capacity.

[0008] In some hospitals and nursing facilities, nurses and healthcare professionals apply various protocols regarding when wound dressings should be changed. These protocols typically include recommendations to change the dressing when wound exudate has reached one, two, or sometimes three of the peripheral edges of the wound pad. This recommendation is usually based on the risk of backflow of wound exudate into the wound site due to dressing saturation. Backflow of wound exudate can lead to maceration of the wound site and surrounding skin, which may prolong the wound healing process.

[0009] However, in many cases, such approaches and suggestions are incorrect. In fact, simply wetting one (or more) edges of the wound pad does not provide the correct indication that the dressing is saturated or that the dressing must be changed.

[0010] Therefore, there is a need for a wound dressing that has improved fluid handling capabilities and provides improved guidance to caregivers and patients regarding when the dressing has reached its full capacity and needs to be replaced. Summary of the Invention

[0011] In view of the above problems, one object of this disclosure is to provide an improvement in the field of absorbable wound dressings that provides favorable guidance on when a dressing needs to be replaced with a new dressing, thereby increasing the total wear time of the dressing.

[0012] According to a first aspect of this disclosure, a wound dressing is provided, comprising a backing layer, an adhesive skin contact layer, and a wound pad disposed between the backing layer and the adhesive skin contact layer, wherein the backing layer and the adhesive skin contact layer are arranged to extend beyond the contour of the wound pad to form a boundary portion, wherein the wound pad includes an upper portion and a lower portion; the upper portion is arranged to contact the backing layer, wherein the surface area of ​​the upper portion is smaller than the surface area of ​​the lower portion, and wherein the upper portion has a higher liquid diffusion capacity than the lower portion.

[0013] This disclosure is based on the understanding that wound dressings, as defined above, provide an improved, greatly simplified, and convenient technical means to indicate to caregivers when a wound dressing has reached its full capacity and needs to be replaced with a new dressing. Furthermore, it improves overall fluid handling capacity and allows the dressing to remain on the skin for a longer period.

[0014] Wound fluid oozing from the wound site is first collected by the lower portion of the wound pad, which then transports the exudate to the upper portion. The upper portion absorbs the fluid and has a higher fluid diffusion capacity than the lower portion. Therefore, the fluid is effectively diffused and distributed across the surface area of ​​the upper portion and will remain primarily in the upper portion until the dressing is saturated.

[0015] When the upper portion becomes saturated, wound exudate will diffuse towards the lower portion of the wound pad and become visible at the edges of the lower portion (due to the smaller surface area of ​​the upper portion). Therefore, merely wetting one or a few edges of the upper portion of the wound pad is not an indication of dressing saturation, as there may still be significant volume within the wound pad. Conversely, once wound exudate reaches the lower portion of the wound pad, this is an indication of backflow of exudate towards the wound site, meaning a dressing change is necessary.

[0016] Another advantage of the dressing as defined above is that wound exudate is effectively transported away from the dressing through evaporation. The higher liquid diffusion capacity of the upper portion ensures that exudate evaporates effectively from the backing layer over a large surface area. This avoids localized saturation of wound exudate and improves the overall liquid handling capacity and breathability of the dressing.

[0017] In an exemplary embodiment, the liquid diffusion capacity of the upper portion can be at least 50% higher than that of the lower portion, preferably at least 100% higher, and more preferably at least 200% higher.

[0018] The gradient of liquid diffusion capacity between the upper and lower portions is preferably large. This is to improve the overall liquid handling capacity of the dressing and ensure that any wound exudate observed at the periphery of the lower portion of the wound pad is indeed due to saturation of wound exudate. In other words, it provides an appropriate indication that the dressing needs to be changed.

[0019] In an exemplary embodiment, the surface area of ​​the upper portion may correspond to 60% to 95% of the surface area of ​​the lower portion, preferably 70% to 90%.

[0020] Therefore, the fluid handling capacity of the upper part (and the entire dressing) is optimized, while the backflow of exudate (towards the lower part) remains easily observable for caregivers.

[0021] In an exemplary embodiment, the upper portion is defined by a peripheral edge, and the lower portion is arranged to extend around the peripheral edge of the upper portion.

[0022] Therefore, the lower portion forms a "boundary portion" around the outline of the upper portion of the wound pad. The area formed between the peripheral edges of the lower and upper portions forms a "humidity indicator area." Wound exudate can be visibly observed at each edge of the lower portion of the dressing. Therefore, the dressing can be placed on the patient in any orientation.

[0023] Typically, the upper part is positioned centered on the lower part.

[0024] In an exemplary embodiment, the lower portion is arranged to extend a distance d1 around the peripheral edge of the upper portion, wherein the distance d1 is 3 mm to 20 mm, preferably 4 mm to 12 mm.

[0025] The area described above allows for easy observation of wound exudate and serves as a reliable means of instructing caregivers to change dressings when necessary. Furthermore, it maintains the fluid volume of the upper portion and the entire dressing.

[0026] In an exemplary embodiment, the upper portion may have a higher liquid retention capacity than the lower portion.

[0027] Therefore, the upper portion has an improved ability to retain absorbed wound exudate. In this respect, it further prevents fluid from leaking back towards the wound site, allowing the skin and wound site to remain relatively dry. This avoids maceration of the wound site.

[0028] In an exemplary embodiment, the upper portion may have a higher absorption capacity than the lower portion.

[0029] The more absorbent upper portion of the cover is used to manage wound exudate and prevent the lower portion of the wound pad (and dressing) from becoming locally saturated. This improves the overall fluid handling capacity and wear time of the dressing.

[0030] In an exemplary embodiment, the lower portion may include a hydrophilic porous material.

[0031] Therefore, the lower section allows for rapid and efficient fluid collection, while enhancing fluid delivery to the upper section. Fluid inlet time is improved; the liquid inlet time is the time required for the fluid to be absorbed into the dressing.

[0032] In an exemplary embodiment, the lower portion may include polyurethane foam.

[0033] Polyurethane foam is a porous hydrophilic foam with a rapid fluid collection rate. It can rapidly transport collected fluid from the wound site upwards; that is, it enters the wound pad vertically.

[0034] Polyurethane foam has a good ability to transport exudate away from the wound site in a direction substantially perpendicular to its plane, while polyurethane foam generally has a relatively poor ability to diffuse and / or distribute liquid in the lateral direction. In this disclosure, materials capable of vertical liquid transport but with poor lateral liquid distribution capabilities are generally preferred.

[0035] In addition, polyurethane foam is conformal and stretchable, which is advantageous because the lower portion is positioned very close to the skin surface.

[0036] In an exemplary embodiment, the upper portion includes a superabsorbent material.

[0037] The superabsorbent material can be superabsorbent polymer (SAP) particles or superabsorbent fiber (SAF).

[0038] Superabsorbent materials can handle large amounts of wound exudate and retain it in the upper part of the wound.

[0039] In an exemplary embodiment, the upper portion may include at least one superabsorbent layer and a liquid distribution layer.

[0040] The upper portion can have a layered structure. This layered pad structure prevents fluid buildup near the skin and improves the overall fluid handling capacity of the dressing.

[0041] The liquid distribution layer may include any material that has the ability to distribute exudate in an effective manner.

[0042] For example, the liquid distribution layer may include a nonwoven material.

[0043] Nonwoven materials have the ability to distribute fluids throughout most of the material, allowing wound exudate to evaporate over a larger surface area. Wound exudate is thus improved through evaporation of the backing layer and overall breathability of the dressing.

[0044] The liquid distribution layer can be placed on top of the superabsorbent layer.

[0045] Dressings with the above structure are suitable for treating large amounts of exudate and preventing maceration of the wound site and the surrounding skin.

[0046] In an exemplary embodiment, the upper portion may include a masking layer arranged to contact the backing layer.

[0047] The masking layer is configured to conceal wound exudate, thus providing a more visually appealing impression. However, the wound exudate remains visible in the lower portion of the wound pad. Therefore, the masking layer is configured only to conceal the upper portion.

[0048] Typically, the backing layer is essentially transparent.

[0049] In an exemplary embodiment, the lower portion of the wound pad is white.

[0050] This improves the visibility of wound exudate reaching the lower part of the wound.

[0051] Other features and advantages of this disclosure will become apparent when examined in conjunction with the appended claims and the following description. Those skilled in the art will recognize that different features of this disclosure can be combined to create embodiments other than those described below, without departing from the scope of this disclosure. Attached Figure Description

[0052] Various aspects of this disclosure, including its particular features and advantages, will be readily understood from the following detailed description and accompanying drawings, wherein: Figure 1 A top perspective view of a medical dressing according to an exemplary embodiment of the present disclosure is shown.

[0053] Figure 2 It shows Figure 1 A cross-sectional view of a medical dressing.

[0054] Figures 3a-3d The reference dressing (dressing A) used in the test of Example 1 was exposed to liquid at a constant flow rate for 15 hours. Figure 3a ), 40 hours Figure 3b ), 44 hours Figure 3c ) and 70 hours ( Figure 3dThe following photos show the dressing from the top (top) and back (bottom).

[0055] Figures 4a-4d The dressing (dressing B) according to an exemplary embodiment of this disclosure, used in the test of Example 1, was exposed to a liquid at a constant flow rate for 15 hours. Figure 3a ), 40 hours Figure 3b ), 44 hours Figure 3c ) and 70 hours ( Figure 3d The following photos show the dressing from the top (top) and back (bottom). Detailed Implementation

[0056] This disclosure will now be described more fully below with reference to the accompanying drawings, which illustrate presently preferred embodiments of the disclosure. However, this disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness and to fully convey the scope of this disclosure to those skilled in the art. The same reference numerals throughout refer to the same elements.

[0057] Figure 1 A wound dressing 100 according to an exemplary embodiment of the present disclosure is shown. The wound dressing 100 includes a backing layer 101, an adhesive skin contact layer 102, and a wound pad 103 disposed between the backing layer 101 and the adhesive skin contact layer 102, wherein the backing layer 101 and the adhesive skin contact layer 102 are arranged to extend beyond the contour of the wound pad 103 to form a boundary portion 104, wherein the wound pad 103 includes an upper portion 103a and a lower portion 103b; the upper portion 103a is arranged to contact the backing layer 101, wherein the surface area of ​​the upper portion 103a is smaller than the surface area of ​​the lower portion 103b, and wherein the upper portion 103a has a higher liquid diffusion capacity than the lower portion 103b.

[0058] The wound dressing disclosed herein allows for improved guidance to caregivers and patients on when dressings need to be changed. The inventors have demonstrated that the dressing can remain on the skin for a longer period and provides a simple and reliable indication of when it should be changed, rather than relying on existing protocols that require dressing changes when wound exudate has reached at least two or three peripheral edges of the wound pad.

[0059] This is clearly demonstrated in Example 1, where the "standard procedure" for dressing changes leads to premature dressing disposal. As shown in Example 1, significant volume remained in the wound pad even after the three peripheral edges of the wound pad had become wet.

[0060] The dressing disclosed herein avoids excessively frequent dressing changes. Therefore, the dressing can remain on the patient's skin for a longer period, and the volume of the wound pad is optimized. Furthermore, unnecessary costs associated with discarded dressings are reduced.

[0061] The term "fluid diffusion capacity" refers to the ability of a fluid (e.g., wound exudate) to diffuse or distribute across a portion or layer of the surface of a wound pad. Fluid diffusion capacity typically refers to the lateral diffusion or distribution of the fluid; that is, along the plane of the wound pad or a portion thereof.

[0062] The fluid diffusion capacity of the upper and lower portions of the wound pad can be assessed qualitatively or quantitatively. For example, fluid diffusion can be assessed by tracking the extent to which fluid is distributed across the surfaces of the upper and / or lower portions over a defined time period. Higher fluid diffusion capacity will be manifested by covering a larger area on the upper portion compared to the lower portion.

[0063] Liquid diffusion capacity can be assessed by applying a known volume of liquid and determining the area covered by the liquid over time. This may involve calculating the liquid diffusion rate per unit time (e.g., cm⁻¹). 2 Liquid diffusion capacity can be measured using standard liquid diffusion test methods known to those skilled in the art. For example, ISO 9073-6 can be used. Measuring liquid diffusion capacity as described in Example 1 is also possible.

[0064] The upper portion of the wound pad has a "higher fluid diffusion capacity" than the lower portion, meaning that the upper portion is more effective at diffusing or distributing wound exudate across its surface area in the lateral direction. Therefore, under the same conditions and over the same time period, fluid will diffuse more quickly and cover a larger area on the upper portion compared to the lower portion.

[0065] The upper part 103a can be attached to the lower part 103b by adhesive or lamination.

[0066] The surface area of ​​the upper portion 103a may correspond to 60% to 95% of the surface area of ​​the lower portion 103b, preferably 70% to 90%.

[0067] Preferably, the upper portion 103a is centrally located on the lower portion 103b.

[0068] However, the invention is by no means limited to this configuration. It is also conceivable that the upper portion 103a may be arranged at an angle or offset relative to the lower portion 103b. In such an embodiment, the dressing is preferably applied to the patient's skin such that the "humidity indicator" area (i.e., the area between the peripheral edges of the lower and upper portions) is positioned in the direction of gravity. For example, if the dressing is applied to a patient's knee, wound exudate will naturally flow downwards. In this respect, the dressing is therefore applied such that the humidity indicator area is positioned downwards.

[0069] Preferably, the liquid diffusion capacity of the upper portion 103a is at least 30% higher than that of the lower portion 103b, for example at least 50%, more preferably at least 100%, and more preferably at least 200%.

[0070] Therefore, under the same conditions (e.g., the same liquid volume and time period), the liquid will diffuse more effectively across the surface of the upper part compared to the lower part.

[0071] For example, if a known volume of liquid (e.g., wound exudate) is applied to two portions, the upper portion 103a will distribute the liquid more rapidly and cover a significantly larger area than the lower portion 103b. More specifically, if the liquid diffusion capacity is 50% higher, the upper portion will cover at least 50% more surface area than the lower portion in the same amount of time. If the liquid diffusion capacity is 100% higher, the upper portion 103a will diffuse the liquid over twice the surface area compared to the lower portion, etc. As described above, the liquid diffusion capacity can be measured using standard tests known to those skilled in the art.

[0072] The gradient of liquid diffusion capacity between the upper portion 103a and the lower portion 103b is preferably as large as possible. This is to provide a reliable way to indicate the saturation of the wound pad and to provide caregivers with a reliable indication of when the dressing needs to be changed.

[0073] In an embodiment, the liquid diffusion capacity of the upper portion 103a can be at least 300% higher than that of the lower portion 103b.

[0074] like Figure 1 As shown, the upper portion is defined by peripheral edges 105a-d. Figure 1 The image shows a square dressing. However, dressings are by no means limited to squares; any shape can be considered. For example, dressings can be rectangular, oval, circular, etc. Dressings can also include multiple protrusions, for example, to fit against the wearer's sacrum or heel.

[0075] Therefore, the peripheral edges 105a-d of the upper portion 103a (and dressing) can be straight or curved.

[0076] The lower portion 103b can be arranged to extend around the peripheral edges 105a-d of the upper portion 103a.

[0077] The lower portion is defined by peripheral edges 109a-d. The area defined between the peripheral edges 105a-d of the upper portion and the peripheral edges 109a-d of the lower portion is designated as the "humidity indicator area." When wound exudate is visible in this area, instruct caregivers to discard the dressing and replace it with a new one.

[0078] Typically, the upper part 103a is centrally positioned on the lower part 103b.

[0079] The lower portion 103b can be arranged to extend a distance d1 around the peripheral edge 105a-d of the upper portion 103a. The distance d1 can be 2mm-20mm, preferably 3mm-20mm, and more preferably 4mm-12mm.

[0080] The distance d1 can vary depending on the size of the dressing. If d1 is too large, fluid handling capacity (and wear time) will be impaired. If d1 is too small, wound exudate will be more difficult to identify in the lower part of the dressing. The distance d1 can be substantially constant around the peripheral edge 105a-d. Alternatively, the distance d1 can vary slightly around the peripheral edge 105a-d.

[0081] The upper portion 103a can have a higher liquid retention capacity than the lower portion 103b.

[0082] As used herein, the term "liquid retention capacity" refers to the ability of a wound pad or wound pad portion to retain and hold wound fluid after absorption. Liquid retention capacity indicates how effectively the upper and / or lower portion of the wound pad retains fluid without release or leakage, even when subjected to external forces. Liquid retention capacity can be measured in the absence or presence of forces, pressure, or centrifugation. Liquid retention capacity can be measured using any standard liquid retention test method known to those skilled in the art. For example, liquid retention capacity can be measured using ISO 9073-12.

[0083] For example, the liquid retention capacity of the upper portion 103a can be at least 50% higher than that of the lower portion, preferably at least 100% higher, and more preferably at least 200% higher.

[0084] This structure helps optimize the overall liquid handling capacity of the dressing and prevents wound exudate from flowing back from the upper part 103a to the lower part 103b.

[0085] The lower part 103b is preferably designed to have a fast liquid collection time.

[0086] The term "liquid acquisition" refers to the ability of a material (e.g., the lower portion 103b) to rapidly absorb liquid (e.g., wound exudate) and transfer it from the surface of the wound pad to the interior; that is, towards the upper portion 103a.

[0087] In this respect, the lower portion 103b may include a hydrophilic and porous material.

[0088] It is also conceivable that the lower part 103b is provided with an incision or perforation to enhance fluid collection into the upper part of the wound dressing.

[0089] The lower portion 103b may include hydrophilic polyurethane foam.

[0090] Hydrophilic polyurethane foam typically has a short liquid ingress time, relatively poor liquid diffusion ability, and is able to quickly collect wound exudate and deliver it to the upper part of the wound pad 103a.

[0091] Polyurethane foam can contain pores with an average pore size ranging from 30 μm to 1000 μm.

[0092] The thickness of the lower portion (e.g., hydrophilic polyurethane foam) can be in the range of 1 mm to 6 mm, for example 1.5 mm to 4 mm, preferably 2 mm to 3.5 mm.

[0093] The thickness of the upper portion 103a of the wound pad can be greater than the thickness of the lower portion 103b. This facilitates the transport of fluid from the lower portion 103b to the upper portion 103a. For example, the thickness of the upper portion 103a can be at least 10%, such as at least 20%, greater than the thickness of the lower portion 103b. The thickness is measured under dry conditions.

[0094] The upper portion 103a may include superabsorbent material.

[0095] Superabsorbent materials can be in the form of particles, fibers, sheets, etc.

[0096] Superabsorbent materials can include superabsorbent polymers (SAPs). Superabsorbent polymers are composed of water-swellable and water-insoluble polymers capable of absorbing large amounts of fluid.

[0097] like Figure 1 and Figure 2 As shown, the upper part can have a layered structure.

[0098] This is to optimize the liquid handling capabilities of wound dressings.

[0099] For example, the upper portion may include at least one superabsorbent layer 106 and a liquid distribution layer 107.

[0100] exist Figure 2 In the middle, the superabsorption layer 106 is arranged below the liquid distribution layer 107.

[0101] This layered pad structure prevents fluid buildup near the skin and improves the dressing's fluid handling capacity. Most wounds contain some exudate, but the level of exudate can vary. In chronic wounds, exudate production can be very high due to persistent inflammation. Dressings with the above-described structure are suitable for managing large amounts of exudate and preventing maceration of the skin around the wound.

[0102] Furthermore, from a microclimate perspective, the wound pad structure of this disclosure is advantageous. Moisture absorbed into the dressing is rapidly transported from the skin to the superabsorbent layer 106 via the lower portion. The liquid distribution layer 107 distributes the wound exudate absorbed by the superabsorbent layer 106 over a large surface area, thereby improving the evaporation of wound exudate through the backing layer. This improves the breathability of the dressing and ensures that bodily fluids do not accumulate near the skin.

[0103] The liquid distribution layer 107 can be a fibrous material.

[0104] For example, the liquid distribution layer 107 may include a nonwoven fabric.

[0105] The nonwoven liquid distribution layer 107 has the ability to distribute fluid throughout most of the material. The liquid distribution layer 107 helps to deflect fluid away from the wound site and lower portion 103b while ensuring maximum utilization of the wound pad's capacity.

[0106] The liquid distribution layer 107 may comprise a meltblown, spunbond, or spunlace nonwoven fabric. Examples of suitable polymers for the nonwoven fabric are polyethylene, polyester, polypropylene, and other polyolefin homopolymers and copolymers. For example, a nonwoven fiber web comprising thermoplastic fibers or mixtures thereof containing polypropylene and polyethylene fibers can be used. The fiber web may have a high thermoplastic fiber content, containing at least 50%, for example, at least 70%, of thermoplastic fibers. The nonwoven fabric may be a mixture of polyester and viscose, for example, in a ratio of 70:30. The basis weight of the nonwoven fabric may be 10 g / m³. 2 Up to 80 g / m 2 Within the range, for example, 20 g / m 2 Up to 50 g / m 2 The liquid diffusion layer can also be a spunbond-meltblown or spunbond-meltblown-spunbond (SMS) fiber web.

[0107] The layers of the upper portion 103a of the wound pad can be attached by adhesive or lamination.

[0108] It is also conceivable that the upper portion 103a of the wound pad comprises compressed hydrophilic polyurethane foam. For example, the upper portion 103a may include multiple compression depressions (not shown). Multiple compression depressions improve the diffusion ability of the polyurethane foam. In other words, the compression depressions improve the ability of the polyurethane foam to diffuse liquid in the lateral direction.

[0109] The upper portion 103a may include multiple incisions (not shown). The term "incision" refers to an incision that removes as little material as possible. Typically, no material is removed at all. Incisions make the upper portion 103a more flexible and better suited to the various movements of the patient or wearer. A more flexible wound pad allows for increased wear time of the wound dressing. Multiple incisions may extend across the surface area of ​​the upper portion 103a. The multiple incisions may be arranged in a discrete pattern, for example, the pattern of the incisions having a shape selected from, for example, a cross, a star, a Y, or an arc (such as a C). Alternatively, the multiple incisions may be arranged in a continuous pattern (e.g., a honeycomb incision pattern).

[0110] like Figure 2 As shown, the upper portion 103a may include a masking layer 108 arranged to contact the backing layer 101.

[0111] Providing a camouflage layer as the top layer of the upper portion 103a of the wound pad can mask wound exudate, which can create a more visually appealing impression. Providing a camouflage layer does not impair the ability to indicate to caregivers that a dressing change is needed, because the exudate remains visible at the edge of the lower portion 103b below.

[0112] The masking layer can be a colored layer that masks blood and any other wound fluids in the wound pad. For example, the masking layer can be gray. The masking layer can also be a layer that helps improve the liquid handling capabilities of the wound dressing. For example, the masking layer can be a nonwoven layer.

[0113] The backing layer 101 is preferably substantially transparent.

[0114] As used herein, the term "substantially transparent" means that wound exudate is visible through the backing layer. In other words, wound exudate on the lower edge of the wound can be identified through the backing layer. The backing layer can be completely transparent, semi-transparent, or translucent.

[0115] The backing layer can be a vapor-permeable membrane, laminate, or sheet. Examples of suitable materials for the backing layer include, but are not limited to, polyurethane films, polyethylene or polyamide films, siloxane films, polyester nonwovens, and laminates of polyester nonwovens and polyurethane films. Suitably, the backing layer is a polyurethane film with a thickness of 5 μm to 40 μm, for example, 15 μm to 25 μm.

[0116] The lower portion 103b of the wound pad may be white or substantially white.

[0117] White can enhance the visualization of wound exudate present at the lower edge of the part.

[0118] The adhesive skin contact layer 102b typically comprises a siloxane-based adhesive.

[0119] Preferably, the adhesive skin contact layer 102 comprises a polymer film provided with an adhesive siloxane gel coating; the siloxane gel coating is arranged to contact the patient's skin during use.

[0120] The adhesive skin contact layer, including the silicone gel, is skin-friendly and easy to remove without causing trauma. It adheres fully to the skin, allowing the dressing to remain in place, but is constructed to maintain its adhesion during repeated removal and reapplication.

[0121] The polymer film simplifies the manufacturing process and provides stability and integrity to the adhesive skin contact layer 102.

[0122] The polymer membrane can be a breathable membrane and can include, for example, polyethylene, polyamide, polyester, or polyurethane. Preferably, the polymer membrane comprises polyurethane. The thickness of the polyurethane membrane can be from 15 μm to 100 μm, for example from 20 μm to 80 μm, preferably from 20 μm to 60 μm.

[0123] Examples of suitable silicone gels for adhesive silicone layers include two-component RTV systems such as Liveo MG-7-9960 (DuPont) and SilGel 612 (Wacker Chemie AG) mentioned herein, as well as NuSil silicone elastomers. In embodiments of the invention, the adhesive may comprise a silicone soft gel having a softness (penetration) of 8 mm to 22 mm, for example 12 mm to 17 mm, measured by a method based on ASTM D 937 and DIN 51580, described in European Patent Application No. 14194054.4. The thickness of the adhesive layer is typically at least 20 μm. The thickness of the adhesive layer may range from 30 μm to 200 μm.

[0124] The adhesive skin contact layer 102 may include multiple perforations. These perforations typically extend through the polymer membrane and the adhesive silicone gel layer. The perforations allow for rapid absorption into the lower portion of the wound pad without compromising its close fit with the skin.

[0125] The wound dressing disclosed herein is suitable for any wound, incision, or scar. The wound dressing can also be used for negative pressure wound therapy (NPWT). In this case, the wound dressing may be referred to as an NPWT dressing.

[0126] In embodiments where the wound dressing is an NPWT dressing, the dressing may include means for connecting the dressing to a negative pressure source and optionally include a canister. For example, the backing layer may include a connecting member and a conduit assembly configured to connect the dressing to a negative pressure source (and to a canister, if present), wherein the conduit assembly is connected to the connecting member of the wound dressing.

[0127] To ensure the transmission of negative pressure, a portion of the wound pad located below the connecting member may include a hole extending into at least a portion of the wound pad, for example, through the upper portion of the wound pad.

[0128] Example 1: A comparative test was conducted using reference dressing A and the dressing (dressing B) according to this disclosure.

[0129] The dressings used in the test (dressing A and dressing B, respectively) were similar in construction, but differed in the relative dimensions between the upper and lower portions of the wound pad. Both dressing A and dressing B, from top to bottom, comprised a polyurethane backing layer; a wound pad comprising a nonwoven distribution layer, a superabsorbent layer, and a polyurethane foam layer, wherein the superabsorbent layer included superabsorbent fibers; and an adhesive skin contact layer comprising a polyurethane film and a silicone gel adhesive.

[0130] The upper portion of dressings A and B both measures 65 × 65 mm. For dressing A, the lower portion measures 65 × 65 mm, and for dressing B, the lower portion measures 75 × 75 mm.

[0131] The surface area of ​​the upper portion of dressing B (including the nonwoven layer and the superabsorbent layer) is 75% of the surface area of ​​the lower portion of the wound pad (polyurethane layer).

[0132] Comparative performance tests of the dressings were conducted using a simulated wound laboratory model and a simulated wound fluid (SWF). The wound model consisted of a transparent polycarbonate plate placed at a 60° angle, with a centrally located fluid inlet hole (10 mm in diameter). The dressing was placed center-to-center.

[0133] SWF consists of horse serum solution (Håtunalab AB, Bro, Sweden), diluted 1:1 with solution A (the formulation of solution A is described in EN13726-1). To enhance the color of the fluid, a few drops of red ink are added to the solution. The solution is then infused using a syringe pump and a 50 ml plastic syringe (with Luer-Lok). TM (Becton Dickinson Plastipak) and with Luer Lok TM The connector's plastic tubing (B. Braun Original Perfusor® Line Type IV - Standard PVC, Melsungen, Germany) pumped SWF into the wound model at a rate of 0.5 ml / h. Testing was conducted in a controlled laboratory environment at 23°C (+ / -2°C) and 50%RH (+ / -5%).

[0134] At the end of each test, photographs were taken from both sides (top and bottom) of the dressing to record the distribution of fluid in the wound pad.

[0135] Figures 3a-3d The results show that dressing A was applied for 15 hours. Figure 3a ), 40h Figure 3b ), 44h Figure 3c ) and 70h ( Figure 3d Fluid diffusion.

[0136] Figures 4a-4d The results of dressing B at 15 hours were shown. Figure 4a ), 40h Figure 4b ), 44h Figure 4c ) and 70h ( Figure 4d Fluid diffusion.

[0137] To identify absorption and fluid leakage issues, tests were conducted at different time settings, and then three different leakage parameters were evaluated. These leakage parameters were: 1) external leakage beyond the dressing boundary, 2) pooling, i.e., fluid residue beneath the dressing when removed from the test equipment, and 3) retention testing to determine fluid backflow when the dressing is exposed to an applied external force of 40 mmHg.

[0138] Retention tests were conducted by placing the removed dressing on a perforated steel plate with 40% of the opening area. A rigid polycarbonate plate covering the entire size of the dressing was applied to the dressing, and a weight associated with 40 mmHg was applied to the plate for 30 seconds. The dressing was weighed before and after the retention test, and the weight difference was recorded.

[0139] The dressings were evaluated at 15h, 40h, 44h and 70h.

[0140] As in Figure 3a As can be seen, for dressing A, at least three peripheral edges of the wound pad were moistened after 15 hours. This would be an indication to change the dressing when applying standard clinical protocols.

[0141] For dressing B, the peripheral edge of the upper portion of the wound pad was also moistened after 15 hours. However, the lower portion of the wound pad remained dry until 44 hours, at which point fluid first reached the peripheral edge of the lower portion of the wound pad. Figure 4c This indicates that the dressing needs to be changed.

[0142] Furthermore, leakage indicator tests showed no external leakage, pooling, or retained leakage (i.e., identified as <0.02 g) at 15, 40, and 44 hours for both dressings A and B. This confirms that the dressing (dressing B) according to this disclosure did not have any leakage problems when the first indication of "dressing change" was observed, i.e., at 44 hours. Therefore, dressing B can remain on the skin for up to three times longer than the recommended standard dressing change protocol.

[0143] However, at 70 h, both dressings A and B showed significant retention leakage (0.44 g and 0.96 g, respectively), indicating that the method can identify leakage problems when the dressings become oversaturated in the simulated wound laboratory model.

[0144] In this way, a simple and reliable technical means is provided for instructing caregivers and / or patients when to change dressings.

[0145] The terms, definitions, and implementation methods of all aspects of this disclosure are applied to other aspects of this disclosure with the necessary modifications.

[0146] Although this disclosure has been described with reference to specific exemplary embodiments thereof, many different changes, modifications, etc. will become apparent to those skilled in the art.

[0147] By studying the accompanying drawings, this disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in practicing this disclosure. Furthermore, in the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

Claims

1. A wound dressing (100) comprising a backing layer (101), an adhesive skin contact layer (102), and a wound pad (103) disposed between the backing layer (101) and the adhesive skin contact layer (102), wherein the backing layer (101) and the adhesive skin contact layer (102) are arranged to extend beyond the contour of the wound pad (103) to form a boundary portion (104), wherein the wound pad (103) comprises an upper portion (103a) and a lower portion (103b); the upper portion (103a) is arranged to contact the backing layer (101), characterized in that, The surface area of ​​the upper portion (103a) is smaller than that of the lower portion (103b), and the upper portion (103a) has a higher liquid diffusion capacity than the lower portion (103b).

2. The wound dressing (100) according to claim 1, wherein the liquid diffusion capacity of the upper portion (103a) is at least 50% higher than that of the lower portion (103b), preferably at least 100% higher, and more preferably at least 200% higher.

3. The wound dressing (100) according to claim 1 or claim 2, wherein the surface area of ​​the upper portion (103a) corresponds to 60% to 95%, preferably 70% to 90%, of the surface area of ​​the lower portion (103b).

4. The wound dressing (100) according to any one of the preceding claims, wherein the upper portion (103a) is defined by a peripheral edge (105a-d), and wherein the lower portion (103b) is arranged to extend around the peripheral edge (105a-d) of the upper portion (103a).

5. The wound dressing (100) according to claim 4, wherein the lower portion (103b) is arranged to extend a distance d1 around the peripheral edge (105a-d) of the upper portion (103a), wherein the distance d1 is 3 mm to 20 mm, preferably 4 mm to 12 mm.

6. The wound dressing (100) according to any one of the preceding claims, wherein the upper portion (103a) has a higher liquid retention capacity than the lower portion (103b).

7. The wound dressing (100) according to any one of the preceding claims, wherein the upper portion (103a) has a higher absorbency than the lower portion (103b).

8. The wound dressing (100) according to any one of the preceding claims, wherein the lower portion (103b) comprises a hydrophilic porous material.

9. The wound dressing (100) according to any one of the preceding claims, wherein the lower portion (103b) comprises polyurethane foam.

10. The wound dressing (100) according to any one of the preceding claims, wherein the upper portion (103a) comprises a superabsorbent material.

11. The wound dressing (100) according to any one of the preceding claims, wherein the upper portion (103a) comprises at least one superabsorbent layer (106) and a liquid distribution layer (107).

12. The wound dressing (100) of claim 11, wherein the liquid distribution layer (107) comprises a nonwoven material.

13. The wound dressing according to any one of the preceding claims, wherein the upper portion (103b) includes a masking layer (108) arranged to contact the backing layer (101).

14. The wound dressing (100) according to any one of the preceding claims, wherein the backing layer (101) is substantially transparent.

15. The wound dressing according to any one of the preceding claims, wherein the lower portion (103b) of the wound pad (103) is white.

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