Tissue dressings

Abstract

A dressing for absorbing compressive and shear force on soft tissue. The dressing can include internal layers that slide with respect to each other to absorb frictional energy. The friction coefficients of the materials and the sliding displacement of the layers can enhance the ability of the dressing to absorb mechanical energy. The thin mask pad and thin absorbent pad can improve the frictional energy absorption of the dressing.

Description

PT-6155-WO-PSP / SMNPH.743WO PCT TISSUE DRESSINGS CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Great Britain Provisional Application No. 2411481.1, filed August 5, 2024, and titled TISSUE DRESSINGS. The aforementioned application is incorporated by reference herein in its entirety. BACKGROUND Field of Use

[0002] Embodiments of the present invention relate generally to tissue dressings, and more specifically to an improved apparatus, system, and method for protecting tissue and managing forces on the tissue. Description of Related Art

[0003] The protection of open or chronic wounds is well known in the art. Tissue dressings are used to protect tissue from the environment and manage forces during wound healing. Areas of tissue that undergo significant mechanical forces, for example weight- bearing areas, are susceptible to pressure ulcers. For example, the heels and the sacral area are susceptible to pressure ulcers. Pressure ulcers can be caused by unrelieved compressive and shear forces that lead to loss of cell homeostasis, inflammation, ischaemia and ultimately cell and tissue death. Certain current dressings are unable to significantly redistribute forces to prevent pressure ulcers in susceptible areas. SUMMARY

[0004] Embodiments of the invention disclosed herein are directed to a tissue dressing and methods of wound treatment. Disclosed embodiments may be useful in the cleaning and treatment of wounds with enhanced force management. Internal shearing of wound dressings can help alleviate some of the mechanical forces that can cause pressure ulcers, but not enough to significantly reduce the risk of these ulcers. A multilayer dressing, as described herein, can include multiple layers that slide with respect to adjacent layers toredistribute mechanical forces. For example, the multilayer wound dressing can distribute shearing forces and compressive forces through internal frictional sliding.

[0005] In some examples, a dressing for preventing tissue damage can include: a top film; a plurality of internal layers, wherein the individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad, and wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

[0006] In some implementations, the total frictional energy absorption effectiveness of the dressing is measurable with a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction. In some implementations, the mask pad has a thickness of 0.4 mm. In some implementations, the mask pad has a thickness of between 0.1 mm and 1 mm. In some implementations, the absorbent pad has a thickness of 2 mm. In some implementations, the absorbent pad has a thickness of between 1 mm and 3 mm. In some implementations, the mask pad is perforated. In some implementations, the absorbent pad includes a plurality of diagonal slits. In some implementations, each diagonal slit of the plurality of diagonal slits includes a plurality of cuts. In some implementations, each diagonal slit of the plurality of diagonal slits includes between 5 and 10 cuts. In some implementations, the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use. In some implementations, the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture. In some implementations, the plurality of diagonal slits are frangible. In some implementations, the absorbent pad is a superabsorber with fibers. In some implementations, the absorbent pad is a superabsorber with particles. In some implementations, the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test. In some implementations, the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test. In some implementations, the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent padand the foam pad of at least 0.75. In some implementations, the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.6. In some implementations, the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm. In some implementations, the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm. In some implementations, the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm. In some implementations, the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test. In some implementations, the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test. In some implementations, the mask pad is cruciform.

[0007] In some examples, a method for manufacturing a dressing for preventing tissue damage can include: providing a tissue contact layer; positioning a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, wherein positioning the plurality of internal layers comprises: positioning a foam pad in contact with the tissue contact layer positioning an absorbent pad in contact with the foam pad; positioning a mask pad in contact with the absorbent pad; and positioning a top film in contact with the mask pad, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

[0008] In some implementations, the method can include conducting a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction to measure the total frictional energy absorption effectiveness of the dressing. In some implementations, the method can include performing non-indexed cutting on the absorbent pad to form a plurality of diagonal slits. In some implementations, each diagonal slit of the plurality of diagonal slits includes a plurality of cuts. In some implementations, each diagonal slit of the plurality of diagonal slits includes between 5 and 10 cuts. In some implementations, the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use. In some implementations, the absorbent pad is configured not to break along the plurality of diagonalslits during manufacture. In some implementations, the plurality of diagonal slits are frangible. In some implementations, the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test. In some implementations, the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test. In some implementations, the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent pad and the foam pad of at least 0.75. In some implementations, the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.6. In some implementations, the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm. In some implementations, the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm. In some implementations, the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm. In some implementations, the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test. In some implementations, the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

[0009] In some examples, a dressing for covering a wound site can include: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing, and wherein the corners of the absorbent pad are configured to show exudate absorbed by the dressing; and a tissue contact layer disposed adjacent to the absorbent pad.

[0010] In some examples, a method for determining an amount of exudate from a wound site can include: providing a dressing comprising: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing; and a tissue contact layer disposed adjacent to the absorbent pad; applying the dressing to a wound site; viewing theexudate absorbed by the corners of the absorbent pad while the dressing is intact and applied to the wound site; and determining, based on the exudate absorbed by the corners of the absorbent pad, an amount of exudate from the wound site.

[0011] In some implementations, the method can include determining, based on the exudate absorbed by the corners of the absorbent pad, whether to remove the dressing.

[0012] In some examples, dressings for preventing tissue damage can include: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad, the absorbent pad comprising a plurality of diagonal slits, wherein the plurality of diagonal slits are frangible; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad.

[0013] In some examples, a total frictional energy absorption effectiveness of the dressing is at least 35%. In some examples, each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts. In some examples, each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts. In some examples, the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use. In some examples, the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture. In some examples, the mask pad is made of polyurethane elastic nonwoven material. In some examples, the mask pad has a weight of between 100 gsm and 300 gsm. In some examples, the mask pad has a thickness of less than 0.7 mm. In some examples, the mask pad has an elastic recovery rate of at least 90%. In some examples, the mask pad has a tensile strength at 10% elongation of between 0.3 kgf / 2.5cm and 0.6 kgf / 2.5cm. In some examples, the mask pad has a tensile strength at 20% elongation of between 0.5 kgf / 2.5cm and 0.9 kgf / 2.5cm. In some examples, the mask pad has a tensile strength at 60% elongation of between 0.8 kgf / 2.5cm and 1.4 kgf / 2.5cm. In some examples, the mask pad comprises formations of thermoplastic polyurethane polymers.

[0014] Disclosed herein are systems and methods for providing medial compression to a tissue site of any of the preceding paragraphs and / or any of the devices, apparatuses, or systems disclosed herein.

[0015] Any of the features, components, or details of any of the arrangements or embodiments disclosed in this application, including without limitation any of the apparatus embodiments and any of the wound site medial compression embodiments disclosed herein, are interchangeably combinable with any other features, components, or details of any of the arrangements or embodiments disclosed herein to form new arrangements and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG.1A shows a top view of an example of a tissue dressing.

[0017] FIG. 1B shows a cross-sectional, side view of the example of the tissue dressing of FIG.1A taken along axis X.

[0018] FIG. 1C shows a top view of the example of the mask pad of the tissue dressing of FIG.1A.

[0019] FIG.1D shows a top view of the example of the absorbent pad of the tissue dressing of FIG.1A.

[0020] FIG. 1E shows a top view of the example of the foam pad of the tissue dressing of FIG.1A.

[0021] FIG.1F shows a perspective view of the example of the tissue dressing of FIG.1A.

[0022] FIG.2A shows a top view of an example of a sacrum tissue dressing.

[0023] FIG. 2B shows a cross-sectional, side view of the example of the sacrum tissue dressing of FIG.2A taken along axis X.

[0024] FIG. 2C shows a perspective view of the example of the sacrum tissue dressing of FIG.2A.

[0025] FIG.3A shows a top view of an example of a heel tissue dressing.

[0026] FIG.3B shows a cross-sectional, side view of the example of the heel tissue dressing 300 of FIG.3A taken along axis X.

[0027] FIG.3C shows a perspective view of the example of the heel tissue dressing of FIG.3A.

[0028] FIG.4A shows a top view of an example of a multisite tissue dressing.

[0029] FIG.4B shows a cross-sectional, side view of the example of the multisite tissue dressing of FIG.4A taken along axis X.

[0030] FIG. 4C shows a perspective view of the example of the multisite tissue dressing of FIG.4A.

[0031] FIG. 5A shows data generated by testing the coefficients of friction of an embodiment of the tissue dressings described herein in a dry state and a moist state.

[0032] FIG. 5B shows data generated by testing the coefficients of friction of an embodiment of the tissue dressings described herein (Dressing B) as opposed to an AL tissue dressing (Dressing A).

[0033] FIGs. 6 shows data generated by testing the vertical compression of an embodiment of the tissue dressings described herein (Dressing B) as opposed to an AL tissue dressing (Dressing A).

[0034] FIGs. 7A shows data generated by testing the inter-layer displacement values for the interface between the foam pad and absorbent pad of an embodiment of the tissue dressings described herein (Dressing B) as opposed to an AL tissue dressing (Dressing A).

[0035] FIGs. 7B shows data generated by testing the inter-layer displacement values for the interface between the absorbent pad and mask pad of an embodiment of the tissue dressings described herein (Dressing B) as opposed to an AL tissue dressing (Dressing A).

[0036] FIGs. 8 shows data generated by testing the frictional energy absorption effectiveness (FEAE) of an embodiment of the tissue dressings described herein (Dressing B) as opposed to an AL tissue dressing (Dressing A).

[0037] FIGs. 9A shows data generated on the coefficients of friction (COFs) between the interface between the foam pad and the absorbent pad.

[0038] FIG.9B shows data generated on the COFs between the interface between the absorbent pad and the mask pad.

[0039] FIG. 10 shows data generated on the vertical compression of Dressing A, Dressing B, and Dressing C in the new and used conditions.

[0040] FIG.11A shows data generated on interlayer displacements at the interface between the foam pad and the absorbent pad.

[0041] FIG.11B shows data generated on interlayer displacements at the interface between the absorbent pad and the mask pad.

[0042] FIG.12 shows the results of the FEAE test for Dressing A, Dressing B, and Dressing C.

[0043] FIG. 13A shows a histogram of tissue exposure to effective strains in a region of interest (ROI) with no dressing and with Dressing B applied to the skin.

[0044] FIG. 13B shows a histogram of tissue exposure to effective strains in an ROI with no dressing and with Dressing B applied to the adipose tissues at the supported posterior heel.

[0045] FIG. 13C shows a histogram of tissue exposure to effective stresses in an ROI with no dressing and with Dressing B applied to the skin.

[0046] FIG. 13D shows a histogram of tissue exposure to effective stresses in an ROI with no dressing and with Dressing B applied to the adipose tissues at the supported posterior heel.

[0047] FIG. 14A shows histograms of the skin exposure to effective strains (left column) and stresses (right column) in the ROI for strain / stress values above the 25thpercentile (top row) and 75thpercentile (bottom row).

[0048] FIG. 14B shows histograms of the adipose tissue exposure to effective strains (left column) and stresses (right column) in the ROI for strain / stress values above the 25thpercentile (top row) and 75thpercentile (bottom row).

[0049] FIG. 15 shows plots of average maximal principal skin (top row) and adipose tissue (bottom row) strains (left column) and stresses (right column) in the ROI as a function of the extent of shear displacements for the ‘no-dressing’ case versus when Dressing B has been applied.

[0050] FIG.16A shows plots of the maximal principal tissue strains along a vertical path that crosses the depth of the adipose tissue in the posterior heel, from the adipose-skin to the adipose-bone interfaces.

[0051] FIG. 16B shows plots of the maximal principal tissue stresses along a vertical path that crosses the depth of the adipose tissue in the posterior heel, from the adipose- skin to the adipose-bone interfaces.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] Preferred embodiments disclosed herein relate to protecting tissue for a human or animal body. Some embodiments disclosed herein relate to wound therapy. Therefore, any reference to a wound herein can refer to a wound on a human or animal body, and any reference to a body herein can refer to a human or animal body. The term “wound” as used herein, in addition to having its broad ordinary meaning, includes any body part of a patient that may be treated using reduced pressure. Wounds and / or wound sites include, but are not limited to, open wounds, pressure sores, ulcers and burns. Open wounds and / or wound sites may also include incisions (e.g., abdominal incisions) or other openings, tears, or fistulas, for example, in the abdominal or peritoneal cavity. Treatment of such wounds can be performed using negative pressure wound therapy, wherein a reduced or negative pressure can be applied to the wound to facilitate and promote healing of the wound. It will also be appreciated that the negative pressure systems and methods as disclosed herein may be applied to other parts of the body, and are not necessarily limited to treatment of wounds.

[0053] Embodiments described herein include dressings which can protect a tissue with enhanced force management. The dressing can include multiple layers of protective films and absorbent pads. The layers can engage in frictional sliding with interfacing layers to absorb mechanical energy exerted on at risk tissue. For example, the layers can slide with respect to one another to reduce the mechanical energy caused by mechanical loading of bodyweight forces on the foot, posterior foot, heel, sacral area, or greater Trochanter. In particular, these layers can reduce the forces on the soft tissue on and near the wound sites.

[0054] The layers of the dressing can allow the dressing to better redistribute mechanical loads, reduce shear forces, maintain proper microenvironmental conditions (such as microclimate and moisture levels) and support tissue perfusion. Multilayer dressings include the benefits of pressure redistribution, friction reduction, and related inflammation modulation, as well as moisture management, which altogether enhance their efficiency in mitigating the pressure ulcer risk. Specifically, multilayer dressings can alleviate soft tissue stresses in weightbearing body regions, by internally deforming under the compressive and shear forces of the bodyweight. The presence of these dressings can absorb some of the mechanical energy acting to deform the soft tissues that would otherwise be transmitted to these tissues directly.

[0055] In an example, the dressing can include a top film, a mask pad, a super absorbent pad, a foam pad, a tissue contact layer, a folded protector, and a plain protector. The multiple layers of materials can enhance absorption, reducing the force exerted on the wound and preventing pooling of fluids, which can hinder healing. The layers can distribute absorbed fluids evenly across the dressing, preventing concentrated areas of pressure on the underlying tissue. The layers can wick fluids away from the tissue or wound site, pulling them further into the pad to reduce the risk of maceration or softening of the tissue or wound edges. The layers can provide cushioning to protect the tissue or wound from external forces, for example friction or impact, which could disrupt healing or cause further damage. The layers can act as a barrier to prevent leakage or contamination. The dressings described herein may protect tissue regions susceptible to damage from mechanical forces, for example soft tissue.

[0056] FIG.1A shows a top view of an example of a dressing 100. FIG.1B shows a cross-sectional, side view of the example of the dressing 100 of FIG.1A taken along axis X. FIG.1C shows a top view of the example of the mask pad of the dressing 100 of FIG.1A. FIG. 1D shows a top view of the example of the absorbent pad of the dressing 100 of FIG.1A. FIG. 1E shows a top view of the example of the foam pad of the dressing 100 of FIG.1A.

[0057] In some examples, the dressing 100 can include a top film 102, which can seal fluid in the wound dressing. The dressing 100 can include a mask pad 104 disposed adjacent to or beneath the top film 102. The dressing 100 can include an absorbent pad 106, or a super absorbent pad, disposed adjacent to or beneath the mask pad 104. The dressing 100 can include a foam pad 108 disposed adjacent to or beneath the absorbent pad 106. The dressing 100 can include a tissue contact layer 110 disposed adjacent to or beneath the foam pad 108. The dressing 100 can include one or more protection layers disposed adjacent to or beneath the foam pad 108. The protection layers can include a plain protector 112 and a folded protector 114.

[0058] In certain examples, each internal layer, for example the mask pad 104, absorbent pad 106, and foam pad 108, can slide against each other to absorb frictional energy. A higher number of internal layers can increase the frictional energy absorption. Frictional energy absorption can mean the ability of the wound dressing to absorb and dissipate mechanical energy through both material shear and layer-to-layer frictional sliding within the dressing. In some implementations, the dressing 100 can have 3 internal layers. In someimplementations, the dressing 100 can have 1-5 internal layers. In some implementations, the dressing 100 can have 1-10 internal layers. A higher sliding displacement distance of each layer can increase the frictional energy absorption. A lower height of the dressing 100 before compression can increase the frictional energy absorption.

[0059] In examples, the top film 102 can be curved to accommodate the pads in the dressing 100. The top film 102 can be hydrophilic or hydrophobic. The top film 102 can be transparent. Suitable materials the top film 102 can be made of include, without limitation, polyurethane, silicone, hydrocolloid, polyethylene, and other polymers and copolymers.

[0060] In some examples, the mask pad 104 can be a masking or protective layer. The mask pad 104 can have a smaller surface area than the top film 102. The mask pad 104 can be rectangular, for example with truncated corners. The mask pad 104 can be cruciform. For example, the mask pad 104 can be shaped like a cross or plus sign. The mask pad 104 can cover the absorbent pad 106, except for at the corners. In some implementations, the mask pad 104 can prevent visibility of exudate from the wound. The exudate can be visible at the corners that are not covered by the mask pad 104. The mask pad 104 can be made of a breathable film. The mask pad 104 can be perforated. The perforations can be evenly spaced across the mask pad 104. The mask pad 104 can be merged or bonded with the top film 102. The mask pad 104 can be in contact with the top film 102 and / or the absorbent pad 106. The mask pad 104 can frictionally slide with respect to the top film 102 and / or the absorbent pad 106.

[0061] In some examples, the corners of the absorbent pad 106 can be visible from above the dressing 100. The top film 102 can be transparent and the mask pad 104 can be cruciform such that the corners of the absorbent pad 106 are uncovered. The absorbent pad 106 can visibly indicate the amount of exudate absorbed by the absorbent pad 106. For example, the absorbent pad 106 can change color to the color of the exudate as the absorbent pad 106 absorbs the exudate. Exudate can mean blood or another fluid absorbed from a wound site or tissue site. As one of skill in the art would understand, exudate may also include irrigated fluid. A user can apply the dressing 100 to a wound site and view the corners of the absorbent pad 106 from above the dressing 100. A user can determine the amount of exudate from the wound site based on the corners of the absorbent pad 106. For example, a user can determine an amount of exudate from the wound site based on the number of corners of the absorbent pad 106 that are filled with exudate.

[0062] In some examples, a user can determine that the dressing 100 should be removed or replaced when four corners of the absorbent pad 106 have absorbed exudate. In some implementations, a user can determine that the dressing 100 should be removed or replaced when between one and four corners of the absorbent pad 106 have absorbed exudate. In some implementations, the mask pad 104 can be shaped to show another portion of the absorbent pad 106 beneath the mask pad 104. For example, the mask pad 104 may include apertures or cut outs to reveal the amount of exudate absorbed by the absorbent pad 106. In some implementations, the mask pad 104 may include an opening in the center to reveal the amount of exudate absorbed by the center of the absorbent pad 106.

[0063] In some examples, the mask pad 104 can be a thin layer. The thinness of the mask pad 104 can reduce vertical compression and displacements with respect to the other internal pads. The thinness of the mask pad can increase the frictional energy absorption of the dressing 100. The mask pad 104 can have a thickness of approximately 0.4 mm. In some embodiments, the mask pad 104 can have a thickness of between approximately 0.1 mm and 1 mm. In some embodiments, the mask pad 104 can have a thickness of between approximately 0.01 mm and 2 mm. Current devices in the field can have a greater thickness, for example approximately 4 mm, which can result in higher vertical compression and displacement and lower frictional energy absorption.

[0064] In some examples, the mask pad 104 can be elastic or extensible. For example, when the mask pad 104 stretches, it can thin. In some examples, fibers of the mask pad 104 can become more spaced apart. In some examples, the mask pad 104 can be made of thermoplastic urethane (TPU) and / or polyurethane elastic nonwoven material. In some examples, the mask pad 104 can have a weight of around 200 grams per square meter (gsm). In some examples, the mask pad 104 can have a weight of between 150 gsm and 250 gsm. In some examples, the mask pad 104 can have a weight of between 100 gsm and 300 gsm. In some examples, the mask pad 104 can have formations of the base TPU polymers distributed across the layer. In some examples, the mask pad 104 can have a density of TPU polymer formations of at least 50 per 100 cm2. In some examples, the mask pad 104 can have a density of TPU polymer formations of between 30 per 100 cm2and 100 per 100 cm2. In some examples, the individual formations of TPU polymer can be less than 3mm in maximum dimension. In some examples, the individual formations of TPU polymer can be less than 1mm to 5 mm in maximum dimension. In some examples, the individual formations of TPU polymer can be less than 0.7 mm to 7 mm in maximum dimension. In some examples, the mask pad 104 can have a tensile strength at 10% elongation of approximately 0.45 kgf / 2.5 cm. In some examples, the mask pad 104 can have a tensile strength at 10% elongation of approximately 0.3 kgf / 2.5cm to 0.6 kgf / 2.5cm. In some examples, the mask pad 104 can have a tensile strength at 20% elongation of approximately 0.7 kgf / 2.5 cm. In some examples, the mask pad 104 can have a tensile strength at 20% elongation of approximately 0.5 kgf / 2.5cm to 0.9 kgf / 2.5cm. In some examples, the mask pad 104 can have a tensile strength at 60% elongation of approximately 1.1 kgf / 2.5 cm. In some examples, the mask pad 104 can have a tensile strength at 60% elongation of approximately 0.8 kgf / 2.5cm to 1.4 kgf / 2.5cm. In some examples, the mask pad 104 can have an elastic recovery rate of at least 90%. In some examples, the mask pad 104 can have an elastic recovery rate of at least 75% to 95%. In some examples, the mask pad 104 can have an absorption capacity of between 0% and 40%. In some examples, the mask pad 104 can have an absorption capacity of between 0% and 60%. In some examples, the mask pad 104 can have a thickness of around or less than 0.7 mm. In some examples, the mask pad 104 can have a thickness of 0.1 mm to 1 mm. Advantageously, the elasticity of the masking pad 104 and / or the tensile strength during elongation can allow the dressing to stretch and recover while masking exudate.

[0065] In some examples, the absorbent pad 106 can be an absorbent layer. The absorbent pad 106 can have a smaller surface area than the top film 102. The absorbent pad 106 can be in contact with the mask pad 104 and / or the foam pad 108. The absorbent pad 106 can frictionally slide with respect to the mask pad 104 and / or the foam pad 108.

[0066] In some examples, the absorbent pad 106 can have slits 120. The slits 120 can be diagonal slits. The slits 120 can be evenly spaced across the absorbent pad. The slits 120 can be made up of smaller slits. The slits 120 can be made up of smaller diagonal slits. The slits 120 can be perforations. The absorbent pad 106 can be perforated. The slits 120 or perforations can improve breathability of the dressing 100. The slits 120 or perforations can improve the force distribution of the dressing 100. The slits 120 of the absorbent pad 106 can work with the elasticity of the masking pad 104 to improve extensibility of the dressing 100.

[0067] In some examples, the slits 120 can improve extensibility and conformability performance of the absorbent pad 106. Current devices in the field can havecorners or edges of the pad fall off due to the positioning of slits. Slits oriented in a specific pattern in relation to the pad profile cut can mitigate the loss of corners to a certain extent. The slits 120 of the absorbent pad 106 can be made up of smaller slits, or cuts, with uncut material between the smaller slits. Advantageously, this can mitigate the loss of corners when a secondary profile cut is made. The slits 120 can be easy to tear during material use due to the small amount of uncut material between the smaller slits. The slits 120 can maintain performance and remain resilient during use. The absorbent pad 106 can remain integral during processing.

[0068] In certain examples, the slits 120 can be made of 7 smaller slits, or cuts. In some embodiments, the slits 120 can be made of 5-10 smaller slits, or cuts. In some embodiments, the slits 120 can be made of 2-15 smaller slits. The absorbent pad 106 can be a hyper-absorber. The slits 120 can have a length of 20 mm. In some embodiments, the slits 120 can have a length of 10-30 mm. In some embodiments, the slits 120 can have a length of 5-50 mm. In some embodiments, the slits 120 can have a length of 1-70 mm. The slits 120 can be angled at 45 degrees with respect to the horizontal or vertical axis of the absorbent pad 106. In some embodiments, the slits 120 can be angled at 30-60 degrees with respect to the horizontal or vertical axis of the absorbent pad 106. In some embodiments, the slits 120 can be angled at 10-90 degrees with respect to the horizontal or vertical axis of the absorbent pad 106.

[0069] In some examples, each smaller slit of the slits 120 can have a length of 2 mm. In some embodiments, each smaller slit of the slits 120 can have a length of 1-3 mm. In some embodiments, each smaller slit of the slits 120 can have a length of 0.5-5 mm. The space between the smaller slits of the slits 120 can be 1 mm. In some embodiments, the space between the smaller slits of the slits 120 can be 0.5-2 mm. In some embodiments, the space between the smaller slits of the slits 120 can be 0.1-2 mm.

[0070] In some examples, the slits 120 can be configured such that each slit 120 is adjacent to perpendicular slits 120. The space between a slit 120 and an end of an adjacent perpendicular slit 120 can be 5 mm. In some embodiments, the space between a slit 120 and an end of an adjacent perpendicular slit 120 can be 1-10 mm. In some embodiments, the space between a slit 120 and an end of an adjacent perpendicular slit 120 can be 0.5-20 mm.

[0071] In some examples, the slits 120 can be frangible, such that the absorbent pad 106 breaks along the slits 120 during use. For example, the space between each cut of theslits can break when routine forces are applied to the dressing 100 during a patient’s movement. The space between slits 120 can also break during use, such that the absorbent pad 106 is broken into multiple pieces during use. Advantageously, this can improve flexibility of the dressing 100. The absorbent pad 106 can be configured to remain intact during manufacture. The slits 120 can be resilient enough to not break during manufacture, but frangible enough to break during use by a patient. When the absorbent pad 106 breaks, the pieces of the absorbent pad 106 can remain within the dressing 100. The slits 120 can be formed using non-indexed cutting. In some implementations, the absorbent pad 106 can break into between 10 and 15 pieces during use. In some implementations, the absorbent pad 106 can break into between 5 and 20 pieces during use. In some implementations, the absorbent pad 106 can break into between 2 and 40 pieces during use.

[0072] In some examples, the slits 120 may be elongate cuts. The slits 120 may be substantially linear or substantially arcuate. For example, the slits 120 may be arcs, circles, and / or ellipses. The slits 120 may be substantially zigzag.

[0073] In some implementations, the absorbent pad 106 can be a superabsorber with fibers. Superabsorbent pads with fibers can be composed of materials with high surface area and capillary action, allowing them to quickly wick away moisture and absorb fluids. Pads with fibers can absorb liquids through their porous structure. These pads may contain a blend of superabsorbent fibers and other materials to enhance absorption and provide additional benefits such as wound healing properties. The absorbent pad 106 can have gelling fibers. The gelling fibers can be absorbent and help manage drainage and removal of dead, damaged, or infected tissue from the wound. The gelling fibers can include synthetic fibers, for example fibers made from sodium carboxymethyl, cellulose, strengthening cellulose fibers, and / or other super-absorbent materials.

[0074] In some implementations, the absorbent pad 106 can be a superabsorber with particles. Superabsorbent pads with particles can consist of small granules or particles embedded within a non-woven fabric or other absorbent material. When liquid comes into contact with the pad, the particles can swell and absorb the liquid. Advantageously, this can allow for rapid absorption and help prevent leakage. The superabsorber with particles can make the dressing 100 stiffer than the superabsorber with fibers. In some embodiments, the dressing 100 with the superabsorber with fibers can have lower coefficients of friction and largerdisplacements. In some embodiments, the dressing 100 with the superabsorber with particles can have higher coefficients of friction and smaller displacements.

[0075] In some examples, the absorbent pad 106 can be a thin layer. The thinness of the absorbent pad 106 can reduce vertical compression and displacements with respect to the other internal pads. The thinness of the absorbent pad 106 can increase the frictional energy absorption of the dressing 100. In an example, the absorbent pad 106 can have a thickness of 2 mm. In some embodiments, the absorbent pad 106 can have a thickness of between approximately 1 mm and approximately 3 mm. In some embodiments, the absorbent pad 106 can have a thickness of between approximately 0.5 mm and approximately 3.5 mm.

[0076] In some examples, the foam pad 108 can be hydrocellular foam. In some embodiments, the foam pad 108 can be polyurethane foam, silicone foam, hydrophilic foam, or alginate foam. The foam pad 108 can have a smaller surface area than at least one of the top film 102, the mask pad 104, and the absorbent pad 106. The foam pad 108 can be in contact with the absorbent pad 106 and / or the tissue contact layer 110. The foam pad 108 can frictionally slide with respect to the absorbent pad 106 and / or the tissue contact layer 110.

[0077] In some examples, the tissue contact layer 110 can include an adhesive for positioning the wound dressing on the patient. For example, the adhesive can be a silicon-gel adhesive. In some embodiments, the adhesive can be acrylic adhesive, zinc oxide adhesive, hydrocolloid adhesive, polyurethane adhesive, and / or acrylate copolymer adhesive.

[0078] In some examples, the plain protector 112 and the folded protector 114 can cover the tissue contact layer 110 when the dressing 100 is not in use. The folded protector 114 can be aligned with the plain protector 112 such that the opening 116 is angled with respect to the tissue contact layer 110. The protection layers can include an opening 116 by which the protection layers can be separated and removed from the wound dressing. The protection layers can cover the tissue contact layer 110 when the dressing 100 is not in use. In some embodiments, the dressing 100 can include multiple plain protectors and / or multiple folded protectors. For example, the dressing 100 can include two folded protectors and / or two plain protectors. The protection layers can be removable. The tissue contact layer 110 can be coupled with the plain protector 112 and folded protector 114 using adhesive. A user can remove the protection layers to expose the tissue contact layer 110 and / or the adhesive.

[0079] In some examples, the layers of the dressing 100 can frictionally slide with respect to each adjacent layer. For example, contacting fibers of the layers can slide within the dressing 100. In some embodiments, fibers of the low-density fibrous layers can slide with respect to contacting layers. The low-density fibrous layers can include the mask pad 104, the absorbent pad 106, and the foam pad 108. The magnitude of the frictional sliding can contribute to reducing the magnitude of the mechanical energy acting on the tissue. For example, the frictional sliding can reduce the mechanical force on soft tissue of the posterior heel or prevent a sacral pressure injury. The magnitude of the frictional sliding can account for at least 30% and / or less than or equal to 45% of the magnitude of the compressive energy. In some implementations, the magnitude of the frictional sliding can account for at least 10% and / or less than or equal to 75% of the magnitude of the compressive energy. In some implementations, the magnitude of the frictional sliding can account for at least 5% and / or less than or equal to 90% of the magnitude of the compressive energy.

[0080] In some examples, the sliding displacement of each internal layer with respect to the adjacent layer can enhance frictional energy absorption. In some embodiments, the internal layers of the dressing 100 can slide a distance of between 0.7 mm and 1.2 mm with respect to adjacent layers. In some embodiments, the internal layers of the dressing 100 can slide a distance of between 0.5 mm and 1.5 mm with respect to adjacent layers. In some embodiments, the internal layers of the dressing 100 can slide a distance of between 0.3 mm and 1.8 mm with respect to adjacent layers. In some embodiments, the internal layers of the dressing 100 can slide a distance of between 0.1 mm and 2 mm with respect to adjacent layers. Advantageously, this arrangement can allow for a frictional energy absorption effectiveness of between 50% and 68%. In some embodiments, this arrangement can allow for a frictional energy absorption effectiveness of between 30% and 88%.

[0081] In certain examples, the coefficient of friction between layers of the dressing 100 in relation to the displacement between the layers when compressed and / or under shear stress can determine how much frictional energy is absorbed by the dressing, and thus not imparted to the at risk tissue. The coefficient of friction between the mask pad 104 and the absorbent pad 106 can be advantageous to maximize frictional energy absorption. The coefficient of friction between the absorbent pad 106 and the foam pad 108 can be advantageous to maximize frictional energy absorption. In some implementations, one or moreof the layers can be dry. In some implementations, one or more of the layers can be moist. Advantageously, the sliding-to-shear ratio of the dressing 100 can increase when the dressing 100 is used for a period of time.

[0082] In some examples, the inter-layer sliding can become easier as the dressing is subjected to repetitive shear loading. Advantageously, the dressing 100 can be configured such that the frictional sliding reduces more compressive force as the dressing 100 is used over a period of time. In some implementations, one or more of the layers are glued to the adjacent layer, for example using a thin layer of acrylic adhesive.

[0083] In some examples, the dressing 100 can allow pressure distribution to help alleviate localized peak pressures. The dressing 100 can reduce friction between the skin and a support surface due to a low-friction outer surface of the top film 102 and / or the tissue contact layer 110. The dressing 100 can prevent moisture accumulation using absorbent materials in the fibrous layers. Advantageously, this can prevent excessive skin hydration that could lead to skin fragility. In some implementations, the dressing 100 can include antimicrobial features.

[0084] In some examples, the foam pad 108 can absorb fluids from the tissue contact layer 110 and distribute them throughout the surface area of the foam pad 108. The absorbent pad 106 can absorb fluids from the foam pad 108. The mask pad 104 can absorb fluids from the absorbent pad 106. Each pad can distribute fluids further outward.

[0085] In some implementations, the top film 102, the tissue contact layer 110, and the protection layers can have a larger surface area than the mask pad 104, absorbent pad 106, and foam pad 108. In some implementations, the top film 102, the tissue contact layer 110, and the protection layers be sealed together at the outermost edges of the dressing 100.

[0086] The dressing 100 can be sized and shaped to cover a tissue area susceptible to being damaged by forces or a wound site. In some examples, the dressing can have a length of approximately 12.5 cm. In some examples, the dressing can have a length of at least 10 cm and less than or equal to 15 cm. In some examples, the dressing can have a length of at least 7.5 cm and less than or equal to 17.5 cm. In some examples, the dressing can have a length of at least 5 cm and less than or equal to 20 cm. In some examples, the dressing can have a length of at least 1 cm and less than or equal to 50 cm.

[0087] In some examples, the dressing can have a width of approximately 12.5 cm. In some examples, the dressing can have a width of at least 10 cm and less than or equal to 15cm. In some examples, the dressing can have a width of at least 7.5 cm and less than or equal to 17.5 cm. In some examples, the dressing can have a width of at least 5 cm and less than or equal to 20 cm. In some examples, the dressing can have a width of at least 1 cm and less than or equal to 50 cm.

[0088] In some implementations, the length and width of the dressing can be approximately equal. In some implementations, the length can be approximately twice the width of the dressing. In some implementations, the length can be approximately three times the width of the dressing. In some implementations, the length can be approximately four times the width of the dressing.

[0089] In some examples, a user may manufacture the dressing 100 by positioning the top film 102 and the intermediate layers above the tissue contact layer 110. The user may position the foam pad 108 above the tissue contact layer 110. The user may position the absorbent pad 106 above the foam pad 108. The user may position the mask pad 104 on the absorbent pad 106. The user may position the film layer 102 above the mask pad 104, for example such that the perimeter of the film layer 102 is in contact with the tissue contact layer 110. In another example, a user may manufacture the dressing 100 by positioning the tissue contact layer 110 and the intermediate layers above the top film 102. The user may position the mask pad 104 beneath the top film 102. The user may position the absorbent pad 106 beneath the mask pad 104. The user may position the foam pad 108 beneath the foam pad 106. The user may position the tissue contact layer 110 beneath the foam pad 108, for example such that the perimeter of the film layer 102 is in contact with the tissue contact layer 110.

[0090] FIG.2A shows a top view of an example of a sacrum dressing 200. FIG.2B shows a cross-sectional, side view of the example of the sacrum dressing 200 of FIG.2A taken along axis X. FIG.2C shows a perspective view of the example of the sacrum dressing 200 of FIG.2A.

[0091] In some examples, the dressing 200 can be similar to the dressing 100 of FIG.s 1A-E. The dressing 200 can be sized and shaped for placement on the small or large sacrum of a patient.

[0092] In some examples, the top film 202 and tissue contact layer 210 of the dressing 200 can include large round portion 220 configured to be placed on the upper area of the sacrum. The top film 202 and tissue contact layer 210 of the dressing 200 can include twosmaller lobes 222 configured to be placed on the lower area of the sacrum. The mask pad 204, the absorbent pad 206, and the foam pad 208 can be round pads in the center of the large round portion 220 of the dressing. The absorbent pad 206 can include an arrow shaped portion with rounded wings that extends into the two smaller lobes 222 of the dressing 200.

[0093] In some examples, the dressing 200 can include splits 230 to improve ease of positioning the dressing 200. For example, the dressing 200 can include three splits on the lobes 222 such that flaps of the lobes 222 can be positioned more freely with respect to each other.

[0094] In some examples, the dressing 200 can include two folded protectors 214. The dressing 200 can include two openings 216 between the plain protector 212 and the folded protectors 214.

[0095] In an embodiment of a small sacrum dressing, the dressing 200 can have a length L of 172.35 mm. In some embodiments, the dressing 200 can have a length L of 150- 200 mm. In some embodiments, the dressing 200 can have a length L of 100-300 mm. In some embodiments, the dressing 200 can have a length L of 50-350 mm. The dressing 200 can have a width W of 174.54 mm. In some embodiments, the dressing 200 can have a width W of 150- 200 mm. In some embodiments, the dressing 200 can have a width W of 100-300 mm. In some embodiments, the dressing 200 can have a width W of 50-350 mm.

[0096] In an embodiment of a large sacrum dressing, the dressing 200 can have a length L of 215.87 mm. In some embodiments, the dressing 200 can have a length L of 200- 250 mm. In some embodiments, the dressing 200 can have a length L of 100-300 mm. In some embodiments, the dressing 200 can have a length L of 50-350 mm. The dressing 200 can have a width W of 230.07 mm. In some embodiments, the dressing 200 can have a width W of 200- 250 mm. In some embodiments, the dressing 200 can have a width W of 100-300 mm. In some embodiments, the dressing 200 can have a width W of 50-350 mm.

[0097] FIG.3A shows a top view of an example of a heel dressing 300. FIG. 3B shows a cross-sectional, side view of the example of the heel dressing 300 of FIG.3A taken along axis X. FIG. 3C shows a perspective view of the example of the heel dressing 300 of FIG.3A.

[0098] In some examples, the dressing 300 can be similar to the dressing 100 of FIG.s 1A-E. The dressing 300 can be sized and shaped for placement on the heel of a patient.

[0099] In some examples, the top film 302 and tissue contact layer 310 of the dressing 300 can include two lobes 332 and a curved rectangle portion 334. The top film 302 and tissue contact layer 310 of the dressing 300 can include splits 330 to allow the two lobes 332 to be positioned more freely with respect to the curved rectangle portion 334. The curved rectangle portion 334 can be positioned on the back of the heel. The lobes 332 can be positioned on the bottom of the heel. In another embodiment, the curved rectangle portion 334 can be positioned on the bottom of the heel and the lobes 332 can be positioned on the back of the heel.

[0100] In some examples, the mask pad 304, the absorbent pad 306, and / or the foam pad 308 can be Y-shaped. The mask pad 304, the absorbent pad 306, and / or the foam pad 308 can include a curved shape in each lobe 332 and a straight shape in the curved rectangular portion 334. The straight shape can be narrower toward the center of the dressing 300.

[0101] In some examples, the dressing 300 can include two folded protectors 314. The dressing 400 can include two openings 316 between the plain protector 312 and the folded protectors 414.

[0102] In some examples, the dressing 300 can have a length L of 252 mm. In some embodiments, the dressing 300 can have a length L of 200-300 mm. In some embodiments, the dressing 300 can have a length L of 100-400 mm. In some embodiments, the dressing 300 can have a length L of 50-450 mm. The dressing 300 can have a width W of 250 mm. In some embodiments, the dressing 300 can have a width W of 200-300 mm. In some embodiments, the dressing 300 can have a width W of 100-400 mm. In some embodiments, the dressing 300 can have a width W of 50-450 mm.

[0103] FIG.4A shows a top view of an example of a multisite dressing 400. FIG. 4B shows a cross-sectional, side view of the example of the multisite dressing 400 of FIG.4A taken along axis X. FIG.4C shows a perspective view of the example of the multisite dressing 400 of FIG.4A.

[0104] In some examples, the dressing 400 can be similar to the dressing 100 of FIG.s 1A-E. The dressing 400 can include a top film 402, a mask pad 404, an absorbent pad 406, a foam pad 408, and a tissue contact layer 410. The dressing 400 can include a plain protector 412 and a folded protector 414 that can be separated at the opening 416. A user canseparate the plain protector from the folded protector 414 at the opening and remove them to expose the tissue contact layer 410. The tissue contact layer 410 can be covered in adhesive.

[0105] In some examples, the dressing 400 can be shaped and sized to fit a variety of tissue regions and wound sites. The dressing 400 can be made of three round or oblong shapes, a clover shape, or trilobed. In some embodiments, the dressing 400 can be made of 2- 5 round or oblong shapes.

[0106] In some examples, the mask pad 404, the absorbent pad 406, and / or the foam pad 408 can be made of three round or oblong shapes, a clover shape, or trilobed.

[0107] Advantageously, the dressing 400 can fit in particular locations on a patient. The dressing 400 can include splits 430 that can allow the lobes to be more freely maneuvered.

[0108] In some examples, the dressing 400 can have a length L of 171.3 mm. In some embodiments, the dressing 400 can have a length L of 150-250 mm. In some embodiments, the dressing 400 can have a length L of 100-300 mm. In some embodiments, the dressing 400 can have a length L of 50-350 mm. The dressing 400 can have a width W of 178.7 mm. In some embodiments, the dressing 400 can have a width W of 150-250 mm. In some embodiments, the dressing400 can have a width W of 100-300 mm. In some embodiments, the dressing 400 can have a width W of 50-350 mm. Test Method

[0109] FIGs. 5A, 5B, 6, 7A, 7B, and 8 show data generated by testing properties of a non-limiting embodiment of the dressings described herein. The test methods are non- limiting examples of means to test properties of dressings. The test methods are combined compression and shear tests. The embodiment of the dressing described herein can be similar to the dressings 100, 200, 300, 400 as shown in FIGs.1A-1F, 2A-2C, 3A-3C, and / or 4A-4C.

[0110] These non-limiting example test methods present a comparative analysis of the ALLEVYN® Life (AL) (manufactured by T.J. SMITH AND NEPHEW, LIMITED, S+N, Kingston upon Hull, UK) and an embodiment of the dressings described herein in their new and simulated used conditions. To quantify their respective pressure ulcer / injury prevention efficiency, several variables were measured, namely: Coefficients of friction and displacements at internal interfaces, as well as vertical compression. The frictional energy absorption effectiveness (FEAE) was calculated for both dressing types from these parameters.When compared to AL dressings, the tested embodiment of the dressings described herein have a significantly thinner absorbent layer and mask layer.

[0111] The non-limiting examples of tests compare FEAE in a pressure ulcer / injury prevention context, when the dressings are exposed to representative in-use loads representative of those applied by the posterior heel of a patient in a supine position. To enable this FEAE comparison, measurements of dressing specimens were cut in half to reveal and quantify potential inter-layer movements. This was conducted by means of a mechano-optical method and apparatus. Additionally, using an electronically-controlled tilting table tribometer, the study encompassed the quantification of internal displacements between adjacent layers and the corresponding coefficients of friction (COFs) to ultimately evaluate the energy absorbed internally in the dressings by layer-on-layer friction and material shear (i.e., the FEAE).

[0112] For each dressing composition, two dressing wear levels were studied: new (as in out-of-the-package) and used, i.e., after being subjected to preconditioning loading representing an accelerated aging process before being tested, both in the clinically relevant moist condition. The used (preconditioned) state was emulated by applying pre-loading cycles to simulate the repetitive simultaneous shear and compression loads that would be exerted by the foot weight of a supine patient, and the movements / repositioning of the patient for the maximum wearing duration of approximately one week. In total, the pre-loading involved 10 loading cycles of coupled compression (exerted by a mass of approximately 1.1 kg), and shear stress (up to 10 N delivered at a speed of 50 mm / min).

[0113] The moist condition accounting for skin perspiration during the intended period of use was simulated while considering that the perspiration rate during sleeping (450- 2280 g / m2 per day) is lower than the moisture vapor transfer rate of the AL dressing (1800- 2600 g / m2 per day). Consequently, there is no substantial moisture accumulation inside the dressing over time. This was verified in convenience samples of healthy participants: a very low weight delta (≈ 0.3 g per dressing overnight) was measured. It was also assumed that the moisture vaporrate of the embodiment of the dressing described herein is comparable. Hence, to simulate the moisture amount accumulated in the dressings, they were left overnight on a flat, semipermeable 1 mm-thick dense chamois cloth, which simulates a sweaty, moistskin. This cloth was moistened by sparsely spraying it with a 0.9% isotonic saline solution, prepared by dissolving 9 g of NaCl in 1 liter of distilled water.

[0114] In the non-limiting example of the test method, two wear levels were studied: new (as in out-of-the-box), and used (after being subjected to an accelerated aging before being tested). The used state was emulated by applying loading cycles to simulate the shear and compression that would be exerted by the foot weight and the movements of the patient for the maximum wearing duration of one week. In total, the pre-loading involved 10 loading cycles of coupled compression (exerted by a mass of approximately 1.1 kg) and shear stress (up to 10 N at a speed of 50 mm / min).

[0115] In the non-limiting example of the test method, two moisture levels were studied: dry (from measurements taken as part of the protocol development), and moist (as the clinically relevant measurements of interest). The perspiration rate during sleeping (450-2280 g / m2 per day [1]) is lower than the moisture vapor transfer rate of ALLEVYN™ LIFE Dressing (1800-2600 g / m2 per day [2], [3]); consequently, there is no substantial moisture accumulation inside the dressing. This was verified in a convenience sample of healthy participants: a very low weight delta (≈ 0.3 g per dressing overnight) was measured. Hence, to simulate the moisture amount in the dressing, the dressings were left overnighton a flat, semipermeable 1 mm-thick dense chamois cloth, which simulates sweaty moist skin. This cloth was moistened by sparsely spraying it with a 0.9% isotonic saline solution, prepared by dissolving 9 g of NaCl in 1 liter of distilled water.

[0116] All combinations of formulation and wear state were tested using 6 samples each. The descriptive statistics of means and standard deviations (SDs) of the studied parameters were calculated. All tables of statistical significance testing, which are included in the Results section, report the outcomes of one-way and two-ways analysis of variance (ANOVA) tests. Tukey-Kramer tests followed the ANOVA tests for pairwise comparisons of the measured variables where the ANOVAs detected statistical significance. A p-value lower than 0.05 was considered statistically significant.

[0117] In the non-limiting example of the test method, the embodiment of the dressing described herein had a length of 17.5 cm and a width of 17.5 cm. The ALLEVYN Life dressing had a length of 15.4 cm and a width of 15.4 cm. For the purpose of the FEAE studies and calculations, both dressing types were considered as three-layer structures as theinnermost and outermost layers, i.e., the adhesive layer and backing film, respectively, are inherently bonded to their respective adjacent layers by design, and remain inseparable during the testing. Consequently, the study focused on the two remaining internal interfaces.

[0118] Raw dressing material COFs measurements and full dressings were used for digital image correlation (DIC) measurements. The COFs and displacements were studied at the two potentially free interfaces internal to the dressing, namely, the interface between the mask pad and the absorbent pad and the interface between the absorbent pad and the foam pad. The influence of the dressing structure and wear state were studied by separately determining the COFs at the relevant interfaces, the compressive behavior, and the layer-on-layer displacements.

[0119] FIG. 5A shows data generated by testing the coefficients of friction of an embodiment of the dressings described herein in a dry state and a moist state. FIG.5B shows data generated by testing the coefficients of friction of an embodiment of the dressings described herein (Dressing B) as opposed to an AL dressing (Dressing A).

[0120] In the non-limiting example of the test method, the measurements of the COFs were performed using an electronically-controlled tilting table tribometer which has been developed in-house at the Gefen laboratory at Tel Aviv University, following an experimental protocol. The angle of the plate of the tilting table is gradually and slowly increased by means of a computer-controlled electrical motor. When the sliding of the weight is initiated due to this gradual inclination, an electrical switch opens instantaneously, causing the motor to immediately stop. The angle ^^ of the plate, at which frictional sliding had started, was then measured using an inclinometer that was thoroughly calibrated at the start of each set of experiments. Contact between the tested layers was ensured using a weight designed to replicate the pressure exerted on the dressing in-use that is reported to be between 15 and 25 mmHg; the exact area of the surface is not specified in the aforementioned literature. The peak pressure can be much higher locally: when measured over a localized / small area (size of the sensor used), reported values go up to 200 mmHg. In order to measure the coefficients of friction under realistic constraints, a pressure level of 30 mmHg was chosen, simulating a worst-case scenario where the calvfdoes not support a substantial weight (and thereby, does not reduce a considerable portion of the loading from the foot). Each specimen of material to be used for testing was cut from sheet of material to fit under the circular weight. A separatesheet sample of material of an adjacent layer is placed on the top of the tilting table tribometer, that will be under the previous weighted circular sample. Each measurement was obtained using a different pair of specimens.

[0121] The wear state statistically significantly lowered the COF values of the embodiment of the dressings described herein at interface 1,2 (between the foam pad and the absorbent pad), but not 2,3 (between the absorbent pad and the mask pad). The p values based on the asterisks shown in FIGs. 5A and 5B are *p<0.05, **p<0.01, ***p<0.001, and ****p<0.0001.

[0122] The embodiment of the dressings described herein, represented as Dressing B, had higher COF values than the AL dressing, represented as Dressing A. The dressings described herein had a COF of between approximately 0.75 and 0.82 between the absorbent pad and the foam pad. The dressings described herein had a COF of between approximately 0.6 and 0.71 between the mask pad and the absorbent pad. Advantageously, due to the higher COF, the dressings described herein can have an enhanced ability to stay securely in place on the tissue region or wound site, which is critical for effective protection and / or healing. A higher coefficient of friction can allow the dressing to have a greater resistance to movement relative to the skin, thereby reducing the likelihood of slippage even when subjected to mechanical forces such as patient movement or external contact. This stability ensures that the dressing maintains optimal coverage of the wound, thereby protecting it from contaminants and maintaining a controlled environment conducive to healing.

[0123] FIGs. 6 shows data generated by testing the vertical compression of an embodiment of the dressings described herein (Dressing B) as opposed to an AL dressing (Dressing A).

[0124] In the non-limiting example of a test method, an apparatus was designed to allow the optical measurement of frictional sliding displacements between interfacing layers of the AL dressing when subjected to realistic in-use loads. In order to apply both a shearing force and a compressive force, it was composed of three main parts: a fixed base, a sliding shearing plate and a compression plate. Since the weight of a foot ranges from 1.29 to 1.43% of the total bodyweight of a patient, and considering an average bodyweight of 76 kg, the mass of a foot and hence the magnitude of the compressive load can be estimated to be 1.1 kg. This was controlled using a force sensing resistor FSR (Interlink Electronics, Camarillo, California)and sampled via a NIDAQmx™ control unit and a custom-made LabVIEW™ program (National Instruments, Austin, Texas). Subsequently, the displacements were measured when the shear force reached the maximum value before sliding that was measured around 6 N. This shear force was dynamically measured using a load cell with a nominal range 2-2 kN ± 0.5% of accuracy connected to a material testing machine (Instron Corp., model 5944, Norwood MA, USA) operating with BlueHill software (Instron Corp.). The displacements and the compressive strain due to these two forces were measured using a high resolution digital video camera of the digital single-lens reflex (DSLR) type (D3500, Nikon Co., Tokyo, Japan).

[0125] Each test specimen was obtained from cutting in half a dressing. The support-facing layer of the dressing was taped to the weight vertically compressing the dressing, and the skin-facing layer was fixed to the plate translating in the shearing direction. Finally, the cut side faced the DSLR camera to allow the recording of the displacements of the dressing layers. To calculate the compressive work of the dressing, the vertical thickness of the dressing was first measured optically on a pre-loaded sample (with a 70 g sample, i.e.6% of the total weight) with no shear forces applied to it. This measurement was then repeated once the sample was loaded and sheared (with 100% of both charges) according to the loading protocol detailed above. The vertical compression ^^ was then calculated for each sample using these two measurements.

[0126] The embodiment of the dressing described herein, represented as Dressing B, exhibited a significantly lower extent of compression displacements compared to the AL dressing, represented as Dressing A. The embodiment of the dressing described herein had a vertical compression of between approximately 0.8 mm and 1.2 mm in the new state. The embodiment of the dressing described herein had a vertical compression of between approximately 0.9 mm and 1.4 mm in the used state. The embodiment of the dressing described herein has a considerably thinner mask pad (~0.4mm) compared with the AL mask pad (~4mm). The embodiment of the dressing described herein has a considerably thinner absorbent pad (~2 mm) compared with the AL absorbent pad (~3.5 mm to 4mm). The p values based on the asterisks shown in FIG.6 are *p<0.05, ***p<0.001, and ****p<0.0001.

[0127] Advantageously, lower compression displacements of internal layers can allow the dressings to maintain their structural integrity and cushioning properties under pressure. The dressing can better resist deformation when subjected to external forces, such asforce on the heel during walking. This stability can ensure consistent pressure distribution across the wound, preventing localized areas of high pressure that could cause pressure ulcers.

[0128] FIGs. 7A shows data generated by testing the inter-layer displacement values for the interface between the foam pad and absorbent pad of an embodiment of the dressings described herein (Dressing B) as opposed to an AL dressing (Dressing A). FIGs.7B shows data generated by testing the inter-layer displacement values for the interface between the absorbent pad and mask pad of an embodiment of the dressings described herein (Dressing B) as opposed to an AL dressing (Dressing A).

[0129] To calculate the frictional sliding work, the displacements of each layer between the resting state and the loaded and sheared state were measured optically. These measurements were taken at the average displacement where the shear force reached 6 N, i.e. the maximum force before sliding. Images were treated using a custom MATLAB™ program using digital image correlation (DIC), a non-contact 2D strain measurement method, allowing to calibrate and track displacements of markers in a chosen region of interest. The testing process was repeated for 6 dressing samples for each interface and condition combination. A 2-ways analysis of variance was used to identify the potential statistically significant effect of the moist and wear levels, with the level of statistical significance set as ^^ < 0.05.

[0130] The effect of the wear state on the studied dressings was further investigated and found to be statistically significant for the interface between the absorbent pad and mask pad for the AL dressing, represented as Dressing A. The embodiment of the dressing described herein, represented as Dressing B, had an interlayer displacement between the absorbent pad and the foam pad of between approximately 0.1 mm and 0.275 mm in the new state. The embodiment of the dressing described herein had an interlayer displacement between the absorbent pad and the foam pad of between approximately 0.12 mm and 0.18 mm in the used state. The embodiment of the dressing described herein had an interlayer displacement between the absorbent pad and the mask pad of between approximately 0.25 mm and 0.5 mm in the new state. The embodiment of the dressing described herein had an interlayer displacement between the absorbent pad and the mask pad of between approximately 0.2 mm and 0.9 mm in the used state. The effect of the wear state on the studied dressings was indistinguishable for the embodiment of the dressings described herein at both its studied interfaces. The p values based on the asterisks shown in FIGs.7A and 7B are *p<0.05, **p<0.01, and ****p<0.0001.

[0131] The dressings described herein may maintain their structural integrity and performance over time, ensuring consistent wound care. Inter-layer sliding can lead to misalignment and separation of the dressing's layers, compromising its ability to provide uniform coverage and protection to the tissue or wound site. Stable inter-layer adhesion can prevent the formation of wrinkles or folds, which can cause discomfort and pressure points on the wound, potentially impeding the healing process. The dressing described herein can provide reliable performance and sustained therapeutic benefits throughout the wear period.

[0132] FIGs.8 shows data generated by testing the FEAE of an embodiment of the dressings described herein (Dressing B) as opposed to an AL dressing (Dressing A). FEAE was defined as the ratio of the frictional sliding work over the work of compressive deformation.

[0133] Under clinically relevant conditions, i.e., used and moist dressing specimens, the FEAE values of the embodiment of the dressing described herein were statistically indistinguishable. The FEAE of the embodiment of the dressing described herein, represented as Dressing B, were greater than those of the AL dressing, represented as Dressing A. The FEAE of the embodiment of the dressing described herein were between approximately 35% and 50% in the new state. The FEAE of the embodiment of the dressing described herein were between approximately 22% and 52% in the used state. The p value based on the asterisk shown in FIG.8 is *p<0.05.

[0134] Advantageously, the dressings described herein can offer enhanced protection and stability due to the higher FEAE. The dressing can reduce the likelihood of trauma or irritation to the wound and surrounding skin, promoting a more comfortable and conducive healing environment. The dressings described herein can absorb and dissipate mechanical energy through both material shear and layer-to-layer frictional sliding within the dressing. The dressings described herein can absorb and dissipate a comparable amount of mechanical energy to the AL dressing through both material shear and layer-to-layer frictional sliding within the dressing, despite the thinner internal layers in the tested embodiment. The example test found that the embodiment of the dressing described herein can absorb and dissipate up to 39% of mechanical energy through both material shear and layer-to-layer frictional sliding within the dressing.

[0135] The complete set of means and SDs for each of the measured variables (N=6) in the non-limiting example of a test method is reported in Table 1. Table 1

[0136] For each studied configuration in the non-limiting example of a test method, ANOVA tests were conducted to compare the properties of the new and used dressings of both types. In Tables 2 and 3, "ns" denotes non-significant differences and an asterisk (*) indicates statistically significant differences for a specific pair. Table 2relevant conditions (used and moist), the FEAE values of the embodiment of the dressings described herein were statistically indistinguishable (and slightly greater) from those of the AL dressings. The embodiment of the dressings describedherein demonstrated more reproducible and stable FEAE behavior between its new and used conditions compared to the AL dressings. The FEAE can be determined by a compression and shear test or another relevant test.

[0138] FIGs. 9A-9B, 10, 11A-11B, and 12 show data generated by testing properties of a non-limiting embodiment of the dressings described herein. The test methods are non-limiting examples of methods to test properties of dressings. The test methods may include any or all of the properties of the test methods described with respect to FIGs.5A, 5B, 6, 7A, 7B, and 8. The test methods include comparing the performances of the dressings when exposed to clinically relevant mechanical loads and moisture conditions in the context of protecting the heel from pressure ulcers / injuries. To enable a quantitative comparison, vertical compression measurements of whole dressings (cut in half to reveal and quantify potential layer-on-layer / inter-layer and intra-layer movements) were conducted. Additionally, the study encompassed the quantification of internal displacements between adjacent layers and the corresponding coefficients of friction (COFs) to evaluate the energy absorbed by layer-on- layer friction. These values were measured by means of a custom-made combined compression and shear test apparatus, simulating the clinical in-use conditions, and an electronically- controlled tilting table tribometer for measuring the COFs. The embodiment of the dressing described herein can be similar to the dressings 100, 200, 300, 400 as shown in FIGs.1A-1F, 2A-2C, 3A-3C, and / or 4A-4C.

[0139] These non-limiting example test methods present a comparative analysis of the ALLEVYN® Life (AL) (manufactured by T.J. SMITH AND NEPHEW, LIMITED, S+N, Kingston upon Hull, UK) and an embodiment of the dressings described herein in their new and simulated used conditions. To quantify their respective pressure ulcer / injury prevention efficiency, several variables were measured, namely: Coefficients of friction and displacements at internal interfaces, as well as vertical compression. The frictional energy absorption effectiveness (FEAE) was calculated for both dressing types from these parameters. When compared to AL dressings, the tested embodiment of the dressings described herein have a significantly thinner absorbent layer and mask layer.

[0140] Dressing A refers to the AL Dressing. Dressing B refers to an embodiment of the dressings described herein. Dressing C refers to another dressing on the market for comparison. Unlike Dressing A and Dressing B, Dressing C has a spreading layer as the bottomlayer, a superabsorbent layer as the middle layer, and a foam layer as the top layer. In contrast, Dressings A and B have an absorbent hydrocellular foam layer as the bottom layer, a superabsorbent layer as the middle layer, and a masking layer as the top layer.

[0141] FIGs.9A shows the COFs between the interface 1,2 (between the foam pad and the absorbent pad). FIG. 9B shows the COFs between the interface 2,3 (between the absorbent pad and the mask pad).

[0142] With respect to FIG. 9A, the first box along the x-axis under “New” and “Used” represents Dressing B, the second box along the x-axis under “New” and “Used” represents Dressing C, and the third box along the x-axis under “New” and “Used” represents Dressing A. Dressing C, the other dressing on the market shown for comparison, generally exhibits a higher COF compared to the AL dressing and the dressing embodiment described herein. Dressing B, the dressing per embodiments described herein, generally shows the lowest COF, particularly when used, indicating a reduction in frictional resistance with wear. The Dressing A material maintains a relatively stable coefficient of friction between the new and used conditions. Statistical analysis highlights significant differences across the materials and conditions, underscoring the impact of wear on the frictional properties of these materials.

[0143] With respect to FIG. 9B, the first box along the x-axis under “New” and “Used” represents Dressing B, the second box along the x-axis under “New” and “Used” represents Dressing C, and the third box along the x-axis under “New” and “Used” represents Dressing A. In the new condition, Dressing B exhibited the highest COF of the dressings, indicating the greatest resistance to sliding. After use, the COF of Dressing B significantly decreased to approximately 0.65, suggesting a reduction in frictional resistance. Similarly, Dressing C’s COF decreased to around 0.7 after use. In contrast, Dressing A's COF remained relatively stable, with a median value of about 0.6, showing only a slight reduction after use. Statistical analysis revealed significant differences in COF between the materials in their new condition, with the Dressing B showing a significantly higher COF compared to Dressing A and Dressing C (p < 0.05). However, after use, the differences between the COF values of the three materials became less pronounced, as all exhibited reduced COF values. The p values for FIGs.9A and 9B are *p≤0.05, **p≤0.01, ***p≤0.001, and ****p≤0.0001.

[0144] FIG. 10 shows the vertical compression of Dressing A, Dressing B, and Dressing C in the new and used conditions.

[0145] The first box along the x-axis represents Dressing B, the second box along the x-axis represents Dressing C, and the third box along the x-axis represents Dressing A. In the new condition, Dressing A demonstrated the lowest vertical displacement, indicating it is the least compressible material of the three dressings when new. Dressing C dressing exhibited a slightly higher displacement with a median of approximately 1.0 mm, while Dressing B had the highest displacement of the dressings at around 1.3 mm, suggesting greater compressibility. After use, all materials showed increased compressibility, with Dressing A's displacement rising significantly, making it the most compressible after usage. Dressing C and Dressing B also exhibited increased displacement after use, though the changes were less pronounced compared to Dressing A. Statistical analysis confirmed significant differences between the materials, particularly highlighting Dressing A's substantial increase in compressibility after use. These findings suggest that while Dressing A is initially less compressible, it undergoes the most significant change with use, whereas the Dressing B and Dressing C maintain more consistent compressibility across conditions. The p values for FIG.10 are *p≤0.05, **p≤0.01, ***p≤0.001, and ****p≤0.0001.

[0146] FIG.11A shows interlayer displacements at interface 1,2 (between the foam pad and the absorbent pad). FIG.11B shows interlayer displacements at interface 2,3 (between the absorbent pad and the mask pad).

[0147] With respect to FIG.11A, the first box along the x-axis under “New” and “Used” represents Dressing B, the second box along the x-axis under “New” and “Used” represents Dressing C, and the third box along the x-axis under “New” and “Used” represents Dressing A. The displacement at interface 1,2 demonstrated that Dressing A exhibited the highest median sliding displacement of the dressings when new (approximately 0.4 mm), but this value significantly decreased after use, indicating a reduction in layer mobility with usage. In contrast, both Dressing B and Dressing C maintained relatively low and consistent sliding displacements around 0.2 to 0.3 mm in both conditions, suggesting stable interlayer interaction over time.

[0148] With respect to FIG. 11B, the first box along the x-axis under “New” and “Used” represents Dressing B, the second box along the x-axis under “New” and “Used” represents Dressing C, and the third box along the x-axis under “New” and “Used” represents Dressing A. Regarding the displacements at interface 2,3, Dressing A showed a low mediansliding displacement (around 0.3 mm) when new, with even lower values observed after simulated use, indicating minimal layer movement under compression. Dressing B displayed a slightly higher median sliding displacement when new (around 0.8 mm), which increases further after usage, suggesting a potential loosening of the interlayer contact with time. Dressing C showed the most significant new-versus-used condition differences. Dressing C has a moderate sliding displacement when new (around 1.0 mm), which notably increases after simulated use, reaching a median of approximately 1.5 mm.

[0149] Dressing A, while showing higher initial sliding displacement at the interface 1,2, stabilized considerably upon usage, with a marked reduction in mobility at both interface 1,2 and 2,3. This suggests that Dressing A becomes more cohesive and less prone to interlayer movement after initial use, which could be beneficial for maintaining dressing integrity over time. In contrast, Dressing B displays consistent, moderate sliding displacements across both interfaces, with a slight increase in mobility, particularly in interface 2,3 after usage. This suggests that Dressing B dressing maintains a balance between mobility and stability, offering some degree of interlayer movement, while not drastically changing its structure and properties with usage. Dressing C exhibits relatively high variability for interface 2,3 in the used condition. This indicates that the behavior of this interface becomes less consistent over time and with use. For FIGs.11A and 11B, the p-values are *p≤0.05, **p≤0.01, ***p≤0.001, and ****p≤0.0001.

[0150] FIG.12 shows the results of the FEAE test for Dressing A, Dressing B, and Dressing C.

[0151] The first box along the x-axis under “New” and “Used” represents Dressing B, the second box along the x-axis under “New” and “Used” represents Dressing C, and the third box along the x-axis under “New” and “Used” represents Dressing A. The average FEAE values indicate that Dressing B and the Dressing C are significantly more effective at absorbing frictional energy compared to Dressing A, both when they are new and after simulated usage. Dressing B maintains high energy absorption with slightly better consistency after use, making it the most reliable option from among those that were tested. Dressing C, while still effective, shows a slight decrease in average FEAE after use and importantly, greater variability, which may suggest some degradation in performance over time, or that the single moving interfaceconcept is more susceptible to variability and inconsistent performance. Advantageously, Dressing B shows less variability and high FEAE. The p-value for FIG.12 is ****p≤0.0001.

[0152] For each studied configuration in the non-limiting example of a test method, average values and standard deviations were determined to compare the properties of the new and used dressings. In Table 4, for both new and used conditions, the coefficient of friction μ1,2 is assumed to be 1, indicating bonded layers, which considers the fact that there is no relative sliding between the layers, as they are essentially fixed together. The sliding displacement values d1,2 for the bonded Dressing C are not provided, because the bonded layers do not allow for measurable interlayer movement. The two methods of calculation are used for the Dressing C, given that this is a 'hybrid' dressing in the sense that it includes both bonded and non-bonded or sliding interfaces, hence the two approaches of calculating FEAE provide a domain estimate rather than certain / specific values. Interface 1,2 was not considered for FEAE for Dressing C with the bonded layers. Table 4 Wear μ₁,₂ μ₁,₂ μ₂,₃ μ₂,₃ d₁,₂ d₂,₃ y FEAE (mm) d₁,₂ (mm) d₂,₃ (mm) y SD (%) FEAE state Av SD Av SD SD SD SD 6 12 13 5 13 15 12 13

[0153] In the non-limiting example test results, Dressing A exhibited the lowest FEAE, with an average of 41% when new, and decreasing slightly to 39% after use. This dressing type also showed a moderate coefficient of friction (~0.84 new, ~0.76 used) and the lowest sliding displacement, indicating less energy absorption and limited interlayer movement compared to the other dressing types studied here. In contrast, Dressing B demonstrated the highest FEAE (~93% when in its used condition) of the dressings with a stable coefficient of friction and consistent vertical compression (i.e., relatively low variability in these parameters), suggesting highly effective performance both when new and after repeated use. Dressing C had a slightly lower FEAE in its used condition (~91%), indicating a good energy absorption capacity overall but it has also exhibited more variability in outcome measures compared to Dressing B, particularly as pertained the displacements at its 2,3 interface. An important consideration related to Dressing C is that it is a hybrid dressing containing one fully sliding interface but additional bonded interfaces. Accordingly, the results for Dressing C (bonded layers) reported in Table 4 indicate a range of performances rather than a specific performance set of parameter values in terms of frictional properties and energy absorption effectiveness when compared to the other dressings. Specifically, for both new and used conditions, the COF of Dressing C at its 1,2 interface, μ1,2 was assumed to be 1, indicating (nearly-)bonded layers, which considers the fact that there is no relative sliding between these (1,2) layers (as they are essentially fixed together). In another form of calculation, the sliding displacement values d1,2 for Dressing C (bonded layers) are not accounted for, because these bonded layers do not allow for measurable interlayer movements and hence meaningful FEAE calculations.

[0154] Dressing B was found to have the most consistent frictional energy absorption effectiveness (FEAE) of the dressings, whereas Dressing C, though being also effective, may experience performance variability during use, very likely due to the single sliding interface that it contains as opposed to the redundancy in such interfaces for Dressing B). Importantly, Dressing C also has just one sliding interface, and hence, no ‘safety margins’ if a mechanical issue such as local (micro)-folding or other physical disorder occurs at that single interface.

[0155] Figures 13A, 13B, 13C, 13D, 14A, 14B, 15, 16A, and 16B relate to non- limiting examples of tests for biomechanical efficacy of Dressing B, a non-limitingembodiment of the dressings described with respect to FIGs.1A-1F, 2A-2C, 3A-3C, and 4A- 4C, in protecting from pressure ulcers / injuries in the posterior heel region. The tests included evaluating contact interactions between a supported heel (for a supine patent position), this dressing (when applied) and a flat medical support surface using a three-dimensional, MRI- based finite element modeling (FE) framework. Tests compared a bare heel versus the same heel anatomy onto which Dressing B was applied. The FE simulations demonstrated that application of Dressing B resulted in considerable alleviation of the strain and stress concentrations within the soft tissues of the posterior heel. Advantageously, Dressing B lowered the strain and stress levels and redistributed the mechanical loading more evenly in these soft tissues, thereby reducing the risk of pressure ulcers / injuries. Further analyses of the protective efficacy index (PEI) data for Dressing B revealed that this dressing completely eliminated the extreme heel soft tissue strain / stress concentrations above the 75th-percentile of the tissue strain / stress domain, and also reduced those strains / stresses above the 25th- percentile of the domain. Advantageously, Dressing B effectively absorbed internal shear loading in the posterior heel soft tissues, as demonstrated in analyses of the soft tissue loading state response to simulated increasing shear displacements, as occurring for example during sliding in bed when the head of the bed is elevated, or during repositioning or transfers. Dressing B was found to have strong protective capacity in pressure ulcer / injury prevention for at-risk, supine patients.

[0156] FIG. 13A shows a histogram of tissue exposure to effective strains in a region of interest (ROI) with no dressing and with Dressing B applied to the skin. FIG.13B shows a histogram of tissue exposure to effective strains in an ROI with no dressing and with Dressing B applied to the adipose tissues at the supported posterior heel.

[0157] For both skin and adipose tissues at the supported posterior heel, Dressing B demonstrated a strong protective effect with respect to tissue strains. Dressing B shifted the tissue strain to lower values, thereby promoting more uniform load distributions across the affected tissues.

[0158] FIG. 13C shows a histogram of tissue exposure to effective stresses in an ROI with no dressing and with Dressing B applied to the skin. FIG.13D shows a histogram of tissue exposure to effective stresses in an ROI with no dressing and with Dressing B applied to the adipose tissues at the supported posterior heel.

[0159] For both skin and adipose tissues at the supported posterior heel, Dressing B demonstrated an increased protective effect with respect to tissue stresses. Dressing B shifted the tissue stresses to lower values, thereby promoting more uniform load distributions across the affected tissues.

[0160] FIG. 14A shows histograms of the skin exposure to effective strains (left column) and stresses (right column) in the ROI for strain / stress values above the 25thpercentile (top row) and 75thpercentile (bottom row). FIG.14B shows histograms of the adipose tissue exposure to effective strains (left column) and stresses (right column) in the ROI for strain / stress values above the 25thpercentile (top row) and 75thpercentile (bottom row).

[0161] Application of Dressing B entirely eliminated the strain and stress concentrations above the 75th-percentile of the strain / stress domain. Dressing B achieved a 100% reduction of these extreme strain and stress concentrations.

[0162] FIG. 15 shows plots of average maximal principal skin (top row) and adipose tissue (bottom row) strains (left column) and stresses (right column) in the ROI as a function of the extent of shear displacements for the ‘no-dressing’ case versus when Dressing B has been applied.

[0163] In each plot of FIG. 15, the uppermost line represents “No dressing” and the lower line represents “Dressing B.” While a patient is sliding in bed in the absence of prophylactic dressings, the soft tissues at the posterior heel in the ROI experience not only greater strain / stress levels compared to when Dressing B is applied, but also, strain / stress levels build up at greater rates (manifested by the higher slopes of all the ‘no-dressing’ curves). Importantly, the plots for Dressing B remain nearly flat as the shear displacements increase, indicating that when this dressing is used there is no substantial growth in the soft tissue exposure to loading even during such sliding in bed episodes.

[0164] FIG.16A shows plots of the maximal principal tissue strains along a vertical path that crosses the depth of the adipose tissue in the posterior heel, from the adipose-skin to the adipose-bone interfaces. FIG. 16B shows plots of the maximal principal tissue stresses along a vertical path that crosses the depth of the adipose tissue in the posterior heel, from the adipose-skin to the adipose-bone interfaces.

[0165] The soft tissue strain / stress values peaked at approximately half the tissue depth, however, Dressing B effectively lowered these peaks in tissue loading. Application ofDressing B prophylactically on the posterior heel considerably alleviated the strain and stress concentrations within the soft tissues in the ROI, and promoted a more uniform distribution of the loading state across these tissues. Dressing B effectively absorbed shear loading in soft tissues of the posterior heel, as demonstrated in the analyses of soft tissue loading state response to increasing shear displacements. For example, this can provide a benefit during sliding in bed when the head of the bed is elevated, the patient is repositioned, or the patient is transferred. Embodiments

[0166] Embodiment 1. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad, and wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

[0167] Embodiment 2. The dressing of Embodiment 1, wherein the total frictional energy absorption effectiveness of the dressing is measurable with a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction.

[0168] Embodiment 3. The dressing of any one of Embodiments 1 or 2, wherein the mask pad has a thickness of 0.4 mm.

[0169] Embodiment 4. The dressing of any one of Embodiments 1-3, wherein the mask pad has a thickness of between 0.1 mm and 1 mm.

[0170] Embodiment 5. The dressing of any one of Embodiments 1-4, wherein the absorbent pad has a thickness of 2 mm.

[0171] Embodiment 6. The dressing of any one of Embodiments 1-5, wherein the absorbent pad has a thickness of between 1 mm and 3 mm.

[0172] Embodiment 7. The dressing of any one of Embodiments 1-6, wherein the mask pad is perforated.

[0173] Embodiment 8. The dressing of any one of Embodiments 1-7, wherein the absorbent pad comprises a plurality of diagonal slits.

[0174] Embodiment 9. The dressing of Embodiment 8, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

[0175] Embodiment 10. The dressing of Embodiment 9, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

[0176] Embodiment 11. The dressing of Embodiment 8, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

[0177] Embodiment 12. The dressing of Embodiment 11, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

[0178] Embodiment 13. The dressing of Embodiment 8, wherein the plurality of diagonal slits are frangible.

[0179] Embodiment 14. The dressing of any one of Embodiments 1-13, wherein the absorbent pad is a superabsorber with fibers.

[0180] Embodiment 15. The dressing of any one of Embodiments 1-4, wherein the absorbent pad is a superabsorber with particles.

[0181] Embodiment 16. The dressing of Embodiment 2, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

[0182] Embodiment 17. The dressing of Embodiment 2, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

[0183] Embodiment 18. The dressing of Embodiment 2, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent pad and the foam pad of at least 0.75.

[0184] Embodiment 19. The dressing of Embodiment 2, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.6.

[0185] Embodiment 20. The dressing of Embodiment 2, wherein the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm.

[0186] Embodiment 21. The dressing of Embodiment 2, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm.

[0187] Embodiment 22. The dressing of Embodiment 2, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm.

[0188] Embodiment 23. The dressing of Embodiment 2, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

[0189] Embodiment 24. The dressing of Embodiment 2, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

[0190] Embodiment 25. The dressing of any one of Embodiments 1-24, wherein the mask pad is cruciform.

[0191] Embodiment 26. A method for manufacturing a dressing for preventing tissue damage, the method comprising: providing a tissue contact layer; positioning a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, wherein positioning the plurality of internal layers comprises: positioning a foam pad in contact with the tissue contact layer positioning an absorbent pad in contact with the foam pad; positioning a mask pad in contact with the absorbent pad; and positioning a top film in contact with the mask pad, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

[0192] Embodiment 27. The method of Embodiment 26, further comprising conducting a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction to measure the total frictional energy absorption effectiveness of the dressing.

[0193] Embodiment 28. The method of any one of Embodiments 26 or 27, further comprising performing non-indexed cutting on the absorbent pad to form a plurality of diagonal slits.

[0194] Embodiment 29. The method of Embodiment 28, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

[0195] Embodiment 30. The method of Embodiment 28, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

[0196] Embodiment 31. The method of Embodiment 28, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

[0197] Embodiment 32. The method of Embodiment 31, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

[0198] Embodiment 33. The method of Embodiment 28, wherein the plurality of diagonal slits are frangible.

[0199] Embodiment 34. The method of Embodiment 27, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

[0200] Embodiment 35. The method of Embodiment 27, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

[0201] Embodiment 36. The method of Embodiment 27, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent pad and the foam pad of at least 0.75.

[0202] Embodiment 37. The method of Embodiment 27, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.6.

[0203] Embodiment 38. The method of Embodiment 27, wherein the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm.

[0204] Embodiment 39. The method of Embodiment 27, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm.

[0205] Embodiment 40. The method of Embodiment 27, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm.

[0206] Embodiment 41. The method of Embodiment 27, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

[0207] Embodiment 42. The method of Embodiment 27, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

[0208] Embodiment 43. A dressing for covering a wound site, the dressing comprising: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing, and wherein the corners of the absorbent pad are configured to show exudate absorbed by the dressing; and a tissue contact layer disposed adjacent to the absorbent pad.

[0209] Embodiment 44. A method for determining an amount of exudate from a wound site, the method comprising: providing a dressing comprising: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing; and a tissue contact layer disposed adjacent to the absorbent pad; applying the dressing to a wound site; viewing the exudate absorbed by the corners of the absorbent pad while the dressing is intact and applied to the wound site; and determining, based on the exudate absorbed by the corners of the absorbent pad, an amount of exudate from the wound site.

[0210] Embodiment 45. The method of Embodiment 44, further comprising determining, based on the exudate absorbed by the corners of the absorbent pad, whether to remove the dressing.

[0211] Embodiment 46. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad, the absorbent pad comprising a plurality of diagonal slits, wherein the plurality of diagonal slits are frangible; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad.

[0212] Embodiment 47. The dressing of Embodiment 46, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%

[0213] Embodiment 48. The dressing of any one of Embodiments 46 or 47, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

[0214] Embodiment 49. The dressing of any one of Embodiments 46-48, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

[0215] Embodiment 50. The dressing of any one of Embodiments 46-49, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

[0216] Embodiment 51. The dressing of Embodiment 50, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

[0217] Embodiment 52. The dressing of any one of Embodiments 46-51, wherein the mask pad is made of polyurethane elastic nonwoven material.

[0218] Embodiment 53. The dressing of any one of Embodiments 46-52, wherein the mask pad has a weight of between 100 gsm and 300 gsm.

[0219] Embodiment 54. The dressing of any one of Embodiments 46-53, wherein the mask pad has a thickness of less than 0.7 mm.

[0220] Embodiment 55. The dressing of any one of Embodiments 46-54, wherein the mask pad has an elastic recovery rate of at least 90%.

[0221] Embodiment 56. The dressing of any one of Embodiments 46-55, wherein the mask pad has a tensile strength at 10% elongation of between 0.3 kgf / 2.5cm and 0.6 kgf / 2.5cm.

[0222] Embodiment 57. The dressing of any one of Embodiments 46-56, wherein the mask pad has a tensile strength at 20% elongation of between 0.5 kgf / 2.5cm and 0.9 kgf / 2.5cm.

[0223] Embodiment 58. The dressing of any one of Embodiments 46-57, wherein the mask pad has a tensile strength at 60% elongation of between 0.8 kgf / 2.5cm and 1.4 kgf / 2.5cm.

[0224] Embodiment 59. The dressing of any one of Embodiments 46-57, wherein the mask pad comprises formations of thermoplastic polyurethane polymers.

[0225] Embodiment 60. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film, wherein the mask pad is made of polyurethane elastic nonwoven material; an absorbent pad disposed adjacent to and in contact with the mask pad, the absorbent pad comprising a plurality of diagonal slits, wherein the plurality of diagonal slits are frangible; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad.

[0226] Embodiment 61. The dressing of Embodiment 60, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%

[0227] Embodiment 62. The dressing of any one of Embodiments 60 or 61, further comprising a plurality of diagonal slits in the absorbent layer.

[0228] Embodiment 63. The dressing of any one of Embodiments 60-62, wherein the mask pad has a weight of between 100 gsm and 300 gsm.

[0229] Embodiment 64. The dressing of any one of Embodiments 60-63, wherein the mask pad has a thickness of less than 0.7 mm.

[0230] Embodiment 65. The dressing of any one of Embodiments 60-64, wherein the mask pad has an elastic recovery rate of at least 90%.

[0231] Embodiment 66. The dressing of any one of Embodiments 60-65, wherein the mask pad has a tensile strength at 10% elongation of between 0.3 kgf / 2.5cm and 0.6 kgf / 2.5cm.

[0232] Embodiment 67. The dressing of any one of Embodiments 60-66, wherein the mask pad has a tensile strength at 20% elongation of between 0.5 kgf / 2.5cm and 0.9 kgf / 2.5cm.

[0233] Embodiment 68. The dressing of any one of Embodiments 60-67, wherein the mask pad has a tensile strength at 60% elongation of between 0.8 kgf / 2.5cm and 1.4 kgf / 2.5cm.

[0234] Embodiment 69. The dressing of any one of Embodiments 60-68, wherein the mask pad comprises formations of thermoplastic polyurethane polymers.

[0235] The foregoing description is that of certain features, aspects and advantages of the present invention, to which various changes and modifications can be made without departing from the spirit and scope of the present invention. Moreover, the negative pressure treatment system disclosed herein need not feature all of the objects, advantages, features and aspects discussed above. Those of skill in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. In addition, while a number of variations of the invention have been shown and described in detail, other modifications and methods of use, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is contemplated that various combinations or subcombinations of these specific features and aspects of embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the discussed negative pressure treatment system.

[0236] Although this disclosure describes certain embodiments, it will be understood by those skilled in the art that many aspects of the methods and devices shown and described in the present disclosure may be differently combined and / or modified to form still further embodiments or acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. Indeed, a wide variety of designs and approaches are possible and are within the scope of this disclosure. No feature, structure, or step disclosed herein is essential or indispensable. Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments havingequivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), substitutions, adaptations and / or alterations as would be appreciated by those in the art based on the present disclosure. While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of protection.

[0237] Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0238] Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

[0239] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the artwill appreciate that in some embodiments, the actual steps taken in the processes illustrated and / or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

[0240] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0241] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and / or steps are included or are to be performed in any particular embodiment.

[0242] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0243] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desiredfunction or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, 0.1 degree, or otherwise.

[0244] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

Claims

WHAT IS CLAIMED IS:

1. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad, and wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

2. The dressing of claim 1, wherein the total frictional energy absorption effectiveness of the dressing is measurable with a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction.

3. The dressing of any one of claims 1 or 2, wherein the mask pad has a thickness of 0.4 mm.

4. The dressing of any one of claims 1-3, wherein the mask pad has a thickness of between 0.1 mm and 1 mm.

5. The dressing of any one of claims 1-4, wherein the absorbent pad has a thickness of 2 mm.

6. The dressing of any one of claims 1-5, wherein the absorbent pad has a thickness of between 1 mm and 3 mm.

7. The dressing of any one of claims 1-6, wherein the mask pad is perforated.

8. The dressing of any one of claims 1-7, wherein the absorbent pad comprises a plurality of diagonal slits.

9. The dressing of claim 8, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

10. The dressing of claim 9, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

11. The dressing of claim 8, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

12. The dressing of claim 11, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

13. The dressing of claim 8, wherein the plurality of diagonal slits are frangible.

14. The dressing of any one of claims 1-13, wherein the absorbent pad is a superabsorber with fibers.

15. The dressing of any one of claims 1-4, wherein the absorbent pad is a superabsorber with particles.

16. The dressing of claim 2, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

17. The dressing of claim 2, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

18. The dressing of claim 2, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent pad and the foam pad of at least 0.

75.

19. The dressing of claim 2, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.

6.

20. The dressing of claim 2, wherein the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm.

21. The dressing of claim 2, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm.

22. The dressing of claim 2, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm.

23. The dressing of claim 2, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

24. The dressing of claim 2, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

25. The dressing of any one of claims 1-24, wherein the mask pad is cruciform.

26. A method for manufacturing a dressing for preventing tissue damage, the method comprising: providing a tissue contact layer; positioning a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, wherein positioning the plurality of internal layers comprises: positioning a foam pad in contact with the tissue contact layer positioning an absorbent pad in contact with the foam pad; positioning a mask pad in contact with the absorbent pad; and positioning a top film in contact with the mask pad, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

27. The method of claim 26, further comprising conducting a compression and / or shear test to determine internal displacements between the plurality of internal layers and corresponding coefficients of friction to measure the total frictional energy absorption effectiveness of the dressing.

28. The method of any one of claims 26 or 27, further comprising performing non-indexed cutting on the absorbent pad to form a plurality of diagonal slits.

29. The method of claim 28, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

30. The method of claim 28, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

31. The method of claim 28, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

32. The method of claim 31, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

33. The method of claim 28, wherein the plurality of diagonal slits are frangible.

34. The method of claim 27, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

35. The method of claim 27, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

36. The method of claim 27, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the absorbent pad and the foam pad of at least 0.

75.

37. The method of claim 27, wherein the dressing is measured in the compression and / or shear test to have a coefficient of friction between the mask pad and the absorbent pad of at least 0.

6.

38. The method of claim 27, wherein the dressing is measured in the compression and / or shear test to have a vertical compression of less than or equal to 1.4 mm.

39. The method of claim 27, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the absorbent pad and the foam pad of less than or equal to 0.275 mm.

40. The method of claim 27, wherein the dressing is measured in the compression and / or shear test to have an interlayer displacement between the mask pad and the absorbent pad of less than or equal to 0.9 mm.

41. The method of claim 27, wherein the mask pad is configured to slide between 0.5 mm and 1.5 mm with respect to the absorbent pad during the compression and / or shear test.

42. The method of claim 27, wherein the absorbent pad is configured to slide between 0.5 mm and 1.5 mm with respect to the foam pad during the compression and / or shear test.

43. A dressing for covering a wound site, the dressing comprising: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing, and wherein the corners of the absorbent pad are configured to show exudate absorbed by the dressing; and a tissue contact layer disposed adjacent to the absorbent pad.

44. A method for determining an amount of exudate from a wound site, the method comprising: providing a dressing comprising: a top film; a mask pad disposed adjacent to the top film, wherein the mask pad is cruciform; an absorbent pad disposed adjacent to the mask pad, wherein corners of the absorbent pad are uncovered by the mask pad, wherein the corners of the absorbent pad are visible from above the dressing; and a tissue contact layer disposed adjacent to the absorbent pad; applying the dressing to a wound site; viewing the exudate absorbed by the corners of the absorbent pad while the dressing is intact and applied to the wound site; and determining, based on the exudate absorbed by the corners of the absorbent pad, an amount of exudate from the wound site.

45. The method of claim 44, further comprising determining, based on the exudate absorbed by the corners of the absorbent pad, whether to remove the dressing.

46. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film; an absorbent pad disposed adjacent to and in contact with the mask pad, the absorbent pad comprising a plurality of diagonal slits, wherein the plurality of diagonal slits are frangible; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad.

47. The dressing of claim 46, wherein a total frictional energy absorption effectiveness of the dressing is at least 35%.

48. The dressing of any one of claims 46 or 47, wherein each diagonal slit of the plurality of diagonal slits comprises a plurality of cuts.

49. The dressing of any one of claims 46-48, wherein each diagonal slit of the plurality of diagonal slits comprises between 5 and 10 cuts.

50. The dressing of any one of claims 46-49, wherein the absorbent pad is configured to break along at least one diagonal slit of the plurality of diagonal slits during use.

51. The dressing of claim 50, wherein the absorbent pad is configured not to break along the plurality of diagonal slits during manufacture.

52. The dressing of any one of claims 46-51, wherein the mask pad is made of polyurethane elastic nonwoven material.

53. The dressing of any one of claims 46-52, wherein the mask pad has a weight of between 100 gsm and 300 gsm.

54. The dressing of any one of claims 46-53, wherein the mask pad has a thickness of less than 0.7 mm.

55. The dressing of any one of claims 46-54, wherein the mask pad has an elastic recovery rate of at least 90%.

56. The dressing of any one of claims 46-55, wherein the mask pad has a tensile strength at 10% elongation of between 0.3 kgf / 2.5cm and 0.6 kgf / 2.5cm.

57. The dressing of any one of claims 46-56, wherein the mask pad has a tensile strength at 20% elongation of between 0.5 kgf / 2.5cm and 0.9 kgf / 2.5cm.

58. The dressing of any one of claims 46-57, wherein the mask pad has a tensile strength at 60% elongation of between 0.8 kgf / 2.5cm and 1.4 kgf / 2.5cm.

59. The dressing of any one of claims 46-57, wherein the mask pad comprises formations of thermoplastic polyurethane polymers.

60. A dressing for preventing tissue damage, the dressing comprising: a top film; a plurality of internal layers, wherein individual layers of the plurality of internal layers are configured to slide with respect to contact with other internal layers, the plurality of internal layers comprising: a mask pad disposed adjacent to the top film, wherein the mask pad is made of polyurethane elastic nonwoven material;an absorbent pad disposed adjacent to and in contact with the mask pad, the absorbent pad comprising a plurality of diagonal slits, wherein the plurality of diagonal slits are frangible; and a foam pad disposed adjacent to and in contact with the absorbent pad; and a tissue contact layer disposed adjacent to the foam pad.

61. The dressing of claim 60, wherein a total frictional energy absorption effectiveness of the dressing is at least 35% 62. The dressing of any one of claims 60 or 61, further comprising a plurality of diagonal slits in the absorbent layer.

63. The dressing of any one of claims 60-62, wherein the mask pad has a weight of between 100 gsm and 300 gsm.

64. The dressing of any one of claims 60-63, wherein the mask pad has a thickness of less than 0.7 mm.

65. The dressing of any one of claims 60-64, wherein the mask pad has an elastic recovery rate of at least 90%.

66. The dressing of any one of claims 60-65, wherein the mask pad has a tensile strength at 10% elongation of between 0.3 kgf / 2.5cm and 0.6 kgf / 2.5cm.

67. The dressing of any one of claims 60-66, wherein the mask pad has a tensile strength at 20% elongation of between 0.5 kgf / 2.5cm and 0.9 kgf / 2.5cm.

68. The dressing of any one of claims 60-67, wherein the mask pad has a tensile strength at 60% elongation of between 0.8 kgf / 2.5cm and 1.4 kgf / 2.5cm.

69. The dressing of any one of claims 60-68, wherein the mask pad comprises formations of thermoplastic polyurethane polymers.

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