CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority to U S. Provisional Application No. 63/010,762, filed on April 16, 2020, which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] The present disclosure relates to dressings for treating wounds. Many wounds exude fluid (e.g., blood, pus, etc.). Dressings for such wounds may include absorbent materials or other features that attempt to manage the fluid, for example with the goal of absorbing all fluid from a wound.

[0003] Some such dressings are used with negative pressure wound therapy (NPWT). In NPWT, a pump is operated to remove air from the dressing to establish a negative pressure (relative to atmospheric pressure) at the wound. The negative pressure can facilitate wound healing. Negative pressure wound therapy can be improved by dressings that provide for the flow of fluid away from the wound while also allowing communication of negative pressure to the wound. Accordingly, dressings and negative pressure wound therapy systems that provide a high amount of fluid storage capacity while maintaining open pathways for fluid communication are desirable.

SUMMARY

[0004] One implementation of the present disclosure is a method of manufacturing a wound dressing The method includes providing a first substrate layer, distributing superabsorbent particles on a first side of the first substrate layer, coupling a second substrate layer to the first side of the first substrate layer such that the superabsorbent particles are positioned between the first substrate layer and the second substrate layer, creating a plurality of holes through the first substrate layer and the second substrate layer, and covering borders of the plurality of holes with a sealant configured to prevent movement of the superabsorbent particles into the plurality of holes.

[0005] In some embodiments, covering the borders of the plurality of holes with the sealant comprises coating the borders with a water-soluble polymer. The water-soluble polymer may be polyvinyl pyrrolidone. Coating the borders with the water soluble polymer may include providing a fluid comprising an organic solvent and the water-soluble polymer, applying the fluid to the first substrate layer and the second substrate layers at least at the borders of the plurality of holes, and allowing the organic solvent to evaporate.

[0006] In some embodiments, applying the fluid to the first substrate layer and the second substrate layer includes distributing the fluid substantially evenly over a full extent of the first substrate layer and the second substrate layer. In some embodiments, applying the fluid to the first substrate layer and the second substrate layers comprises aiming the fluid at the borders of the plurality of holes. [0007] In some embodiments, covering the borders of the plurality of holes with the sealant includes laminating a first film layer to a second film layer at the plurality of holes with the first substrate layer and the second substrate layer positioned between the first film layer and the second film layer. The method may also include providing openings through the first film layer and the second film layer at the plurality of holes. The first film layer and the second film layer may include a water-soluble film material and/or a water-insoluble film material.

[0008] In some embodiments, covering the borders of the plurality of holes with the sealant includes coupling the first substrate layer to the second substrate layer along the borders by applying a glue to the borders.

[0009] Another implementation of the present disclosure is a composite layer for use in a wound dressing. The composite layer includes a first substrate layer, a second substrate layer coupled to the first substrate layer, and superabsorbent particles distributed between the first substrate layer and the second substrate layer. A plurality of open channels extend through the composite layer.

[0010] In some embodiments, the first substrate layer is configured to prevent the superabsorbent particles from moving therethrough and the second substrate layer is configured to prevent the superabsorbent particles from moving therethrough. The composite layer may include a sealant at borders of the plurality of open channels. The sealant is configured to confine the superabsorbent particles between the first substrate layer and the second substrate layer.

[0010] In some embodiments, the sealant is water soluble. The sealant may include polyvinyl pyrrohdone. In some embodiments, the sealant includes a first film sealed to a second film at the borders of the plurality of open channels.

[0011] Another implementation of the present disclosure is a negative pressure wound therapy system. The system includes a dressing. The dressing includes an external drape layer, a wound contact layer, and a composite layer positioned between the external drape layer and the wound contact layer. The composite layer includes a first substrate layer, a second substrate layer coupled to the first substrate layer, and superabsorbent particles distributed between the first substrate layer and the second substrate layer. A plurality of open channels extend through the composite layer. In some embodiments, the dressing also includes a sealant provided at least at borders of the plurality of open channels.

[0012] In some embodiments, the negative pressure wound therapy system also includes a tube coupled to the dressing, a pump in fluid communication with the dressing via the tube, and an off- dressing fluid collector in fluid communication with the dressing via the tube.

[0013] In some embodiments, the water-soluble sealant is configured to resist movement of fluid to the superabsorbent particles for an initial time period such that fluid is allowed to move to the off- dressing fluid collector during the initial time period. The water-soluble fluid may be configured to break down during the initial time period to allow the superabsorbent particles to absorb the fluid during a subsequent time period. A duration of the initial time period may be associated with a capacity of the off-dressing fluid collector.

[00145] In some embodiments, the dressing also includes a manifold layer positioned between the composite layer and the wound contact layer. In some embodiments, a glue is positioned at borders of the open channels to seal the first substrate layer to the second substrate layer at the borders.

BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is an exploded view of a superabsorbent dressing, according to an exemplary embodiment.

[0016] FIG. 2 is a perspective view of the superabsorbent dressing of FIG. 1, according to an exemplary embodiment.

[0018] FIG. 3 is a cross-sectional side view of the dressing of FIG. 1, according to an exemplary embodiment.

[0019] FIG. 4 is a first schematic illustration of layers of the dressing of FIG. 1, according to an exemplary embodiment.

[0020] FIG. 5 is a second schematic illustration of layers of the dressing of FIG. 1, according to an exemplary embodiment.

[0021] FIG. 6 is an illustration of a negative pressure wound therapy system with a superabsorbent dressing, according to an exemplary embodiment.

[0022] FIG. 7 is a top view of the superabsorbent structure of the dressing of FIG. 6, according to an exemplary embodiment.

[0023] FIG. 8 is a top view of the superabsorbent structure of FIG. 7 provided with a film seal, according to an exemplary embodiment.

[0024] FIG. 9 is a flowchart of a process for manufacturing a dressing, according to an exemplary embodiment.

[0025] FIG. 10 is a flowchart illustrating operation of negative pressure wound therapy using the system of FIG. 6, according to an exemplary embodiment.

[0026] FIG. 11 is a storyboard illustration of absorption by the superabsorbent structure overtime, according to an exemplary embodiment.

DETAIFED DESCRIPTION

[0027] Referring now to FIG. 1, an exploded view of a superabsorbent dressing 100 is shown, according to an exemplary embodiment. The superabsorbent dressing 100 may be similar to, for example, a KERRAFOAM™ Gentle Border Foam Dressing by Crawford Woundcare Fimited and KCI™.

[0028] In the example shown, the superabsorbent dressing includes an outer film layer (drape) 102, a first wicking layer 104 adjacent the outer film layer 102, a hydrophilic foam layer 105 adjacent the first wicking layer 104, a superabsorbent structure 106 adjacent the first wicking layer 104, a second wicking layer 108 adjacent the superabsorbent structure 106, and a wound contact layer 110 adjacent the second wicking layer 108. As shown, the first wicking layer 104 is between the drape 102 and the hydrophilic foam layer 105, the hydrophilic foam layer 105 is between the first wicking layer 104 and the superabsorbent structure 106, the superabsorbent structure 106 is between the hydrophilic foam layer 105 and the second wicking layer 108, and the second wicking layer 108 is between the hydrophilic foam layer 105 and the wound contact layer 110.

[0029] In the example shown, the drape 102 includes a non-wound-facing (first) side 112 and a wound-facing (second) side 114. The first side 112 is positioned to be exposed to an ambient environment, while the second side 114 faces the first wicking layer 104. The first wicking layer 104 has a non-wound-facing (first) side 118 and a wound-facing (second side) 120, with the first side 118 of the first wicking layer 104 facing (e.g., contacting) the second side 114 of the drape 102. The second side 120 of the first wicking layer 104 faces (e.g., contacts) a first side 124 of the hydrophilic foam layer 105. The hydrophilic foam layer 105 also has a second side 126 opposite the first side 124 and facing (e.g., contacting) a first side 130 of the superabsorbent structure 106. The superabsorbent structure 106 also includes a second side 132 opposite the first side 130 and facing (e.g., contacting) a first side 134 of the second wicking layer 108. The second wicking layer 108 also includes a second side 136 opposite the first side 134 and facing (e.g., contacting) a first side 142 of the wound contact layer 110. The wound contact layer 110 also includes a second side 144 opposite the first side 142 and configured to contact a wound of a patient.

[0030] The outer film layer (drape) 102 is a protective film, for example configured to maintain a moist and protective healing environment at a wound bed when the dressing 100 is applied to a wound. For example, the drape 102 may include a hydrophilic polymer film, for example made of polyurethane. The outer film layer 102 may have a thickness in a range between approximately 15 microns and approximately 50 microns, for example approximately 30 microns. The outer film layer 102 may have a moisture vapor transmission rate (upright cup test) of approximately 2600g/m ² /day or greater. In some embodiments, the drape 102 may comprise a polyurethane film layer with a minimum MVTR of about 800 g/m2/24 hours. The first side 112 of the drape 102 may be water resistant. The drape 102 may form a bacteria barrier that substantially prevents movement of bacteria therethrough.

[0031] The drape 102 includes a periphery (perimeter) 116. In some embodiments, the wound facing (second) side 114 of the drape 102 may be coated with an adhesive, such as an acrylic adhesive. For example, the adhesive may be positioned on substantially a full extent of the second side 114 of the drape 102, such that the second side 114 of the drape 102 may be adhered to the first side 118 of the second wicking layer 108. In other embodiments, the adhesive is positioned only along the periphery 116 of the drape 102.

[0032] The first wicking layer 104 may include a soft nonwoven material, for example a textile material. For example, the first wicking layer 104 may be composed of a polyethylene nonwoven material having a thickness in a range between approximately 0.85 millimeters and 1.15 millimeters, for example 0.95 millimeters. The first wicking layer 104 may be flexible and configured to stretch to allow for swelling of the superabsorbent structure 106. The first wicking layer 104 may also facilitate fluid handling, for example by distributing fluid laterally across the dressing 100 to improve evaporation of fluid through the outer film layer 102. The first wicking layer 104 may also be configured to contribute to the dressing 100 being soft to the touch when contacted on the outer film layer 102. The first wicking layer 104 is thereby configured to improve the comfort of the dressing 100 for a patient. In some embodiments, the first wicking layer 104 is omitted. The first wicking layer 104 includes a first side 118 and a second side 120 opposite the first side 118.

[0033] The first wicking layer 104 includes a periphery (perimeter) 122. In some embodiments, the periphery 116 of the drape 102 may bound an area larger than the periphery 122 of the first wicking layer 104. The area bound by the periphery 122 of the first wicking layer 104 may be contained within the area bound by the periphery 116 of the drape 102.

[0034] The hydrophilic foam layer 105 may include an open-cell foam, for example a polyurethane foam. The hydrophilic foam layer 105 may have a thickness of approximately 2 millimeters. Other thicknesses may be used in other embodiments. The hydrophilic foam layer 105 is configured to absorb fluid and allow fluid to flow therethrough, for example from the superabsorbent structure 106 to the first wicking layer 104. The hydrophilic foam layer 105 may be hydrophilic, such that the hydrophilic foam layer 105 is configured to attract water or other fluid, such as a wound fluid. The hydrophilic foam layer 105 may be flexible and compressible, thereby improving comfort of the dressing 100.

[0035] The hydrophilic foam layer 105 includes a first side 124 and a second side 126 opposite the first side. The hydrophilic foam layer 105 also includes a periphery (perimeter) 128. In some embodiments, the periphery 122 of the first wicking layer 104 bounds an area lager than the periphery 128 of the foam layer. The area bound by the periphery 128 of the foam layer 105 may be contained within the area bound by the periphery 122 of the first wicking layer 104.

[0036] The superabsorbent structure 106 may include a superabsorbent material and one or more substrate or binding materials, and is configured to absorb fluid from a wound bed. As described in further detail below, the superabsorbent structure 106 may be constructed as a composite layer that includes a first nonwoven layer and a second nonwoven layer with a polyvinyl acetate (PVA) adhesive layer disposed on a side of the first nonwoven layer facing the second nonwoven layer. For example, a PVA adhesive layer may be disposed on a side of the second nonwoven layer facing the first nonwoven layer. In some embodiments, a superabsorbent particle layer, such as a sodium polyacrylate superabsorbent powder may be sprayed (or otherwise applied) onto either or both of the PVA adhesive layers. The PVA adhesive layer coated faces of the first nonwoven layer and the second nonwoven layer may be brought into contact, such that the first nonwoven layer is bonded to the second nonwoven layer, with the superabsorbent particle interspersed between throughout the PVA adhesive. The PVA adhesive may intersperse into the first and second non-woven layers. The faces coated with the PYA adhesive may be coextensive. The superabsorbent structure 106 may be heated to cure the PVA adhesive to form the composite layer. In some embodiments, the nonwoven layers are configured to provide fluid wicking to facilitate distribution of fluid laterally in the superabsorbent structure 106. The superabsorbent particle layer is configured to absorb fluid, for example swelling when fluid is absorbed to increase a fluid handling capacity of the dressing 100.

The PVA adhesive may be applied so as to be permeable to fluid and to allow a degree of swelling of the superabsorbent particles.

[0037] The superabsorbent structure 106, once cured, may have a certain degree of rigidity and may substantially be provided with a mechanically-disrupted structure that improves the flexibility and conformability of the superabsorbent structure 106. For example, the superabsorbent structure 106 may be scrunched, scored, stretched, folded, manipulated, etc. such that the superabsorbent structure 106 includes a mechanically-disrupted structure that may include cracks, wrinkles, breaks, creases, internal disconnections, breakdowns in the adhesion between portions of the superabsorbent structure 106, etc. which may increase the conformability and/or flexibility of the superabsorbent structure 106. [0038] The composite layer forming the superabsorbent structure 106 may have a thickness in a range of about 0.75 mm to about 1.15 mm (e.g., about 0.95 mm with a tolerance of about 0.2 mm) when substantially dry, and may expand when the superabsorbent structure 106 absorbs fluid.

[0039] The superabsorbent structure 106 has a first side 130 and a second side 132 opposite the first side 130. The superabsorbent structure 106 has a periphery (perimeter) 133. The periphery 133 of the superabsorbent structure 106 may bound an area coextensive with the area bound by the periphery 128 of the foam layer 105. As positioned in the dressing 100 of FIG. 1, the periphery 133 of the superabsorbent structure 106 may align with the periphery 128 of the foam layer 105.

[0040] The second wicking layer 108 may include a nonwoven material, for example a textile. For example, the second wicking layer 108 may be composed of a polyethylene nonwoven material having a thickness in a range between approximately 0.85 millimeters and 1.15 millimeters, for example 0.95 millimeters. The second wicking layer 108 may be sufficiently flexible and configured to stretch to allow for and accommodate swelling of the superabsorbent structure 106. In the example shown, the wicking layer is configured to provide for fluid flow from a wound bed to the superabsorbent structure 106 and to distribute wound exudate (e.g., horizontally/laterally across the dressing 100) to substantially maximize the absorption capacity of the dressing 100. The second wicking layer 108 may thereby reduce a risk of maceration, increase the fluid capacity of the dressing 100, and increase the duration for which the dressing 100 can be continuously applied to a wound. [0041] The second wicking layer 108 includes a first side 134 and a second side 136 opposite the first side 134. The second wicking layer 108 also includes a periphery (perimeter) 138. The periphery 138 of the second wicking layer 108 may bound an area coextensive with the area bound by the periphery 122 of the first wicking layer 104. The second wicking layer 108 and the first wicking layer 104 may be coupled together around the periphery 138 and the periphery 122 to form a “tea- bag” structure that surrounds and encloses the super absorbent structure 106 and foam layer 105 in a “free-floating” manner.

[0042] The wound contact layer 110 is configured to contact a wound bed while substantially preventing ingrowth of healing tissue to the dressing 100. The wound contact layer 110 may include a perforated silicone material. The wound contact layer 110 may also include a silicone adhesive, for example an adhesive that is permeable to moisture. In some embodiments, the wound contact layer 110 may comprise a silicone adhesive which loses tack when in contact with water or a wound fluid. For example, the wound contact layer 110 may adhere to portions of the epidermis which are substantially dry, but adhere with reduced tack or not adhere to portions of the wound which are wet. Advantageously, in some example embodiments, the silicone adhesive of the wound contact layer 110 may permit at least portions of the dressing to be removed from and re-adhered to the epidermis and/or wound site, facilitating the practitioner’s ability to visually observe the wound site.

[0043] As shown in FIG. 1, the wound contact layer 110 includes a plurality of perforations 140 through the wound contact layer. The perforations 140 can allow fluid to move across the wound contact layer 110, for example from a wound to the second wicking layer 108. In illustrative embodiments, the wound contact layer 110 may have a thickness of about 30 micrometers. The wound contact layer 110 includes a first side 142 and a second side 144 opposite the first side 142.

The second side 144 is configured to contact the wound. A periphery (perimeter) 146 of the wound contact layer 110 defines the extent of the wound contact layer 110. The periphery 146 of the wound contact layer 110 may bound an area coextensive with the area bound by the periphery 116 of the drape 102.

[0044] Referring now to FIG. 2, an assembled isometric view of the dressing 100 is shown, according to an exemplary embodiments. As shown in FIG. 2, the drape 102 and the wound contact layer 110 are visible, with the first wicking layer 104, the hydrophilic foam layer 105, the superabsorbent structure 106 and the second wicking layer 108 assembled in the form of a “tea-bag” or pouch and contained between the drape 102 and the wound contact layer 110.

[0045] Referring now to FIG. 3, a cross-sectional schematic diagram is shown, with the section taken along section line 3 of FIG. 2, illustrating the dressing 100 in use on a tissue site, according to an exemplary embodiment. In the example of FIG. 3, the tissue site includes a wound 302 that extends through the epidermis 304 and the dermis 306 and into subcutaneous tissue 308.

[0046] As shown in FIG. 3, the first wicking layer 104 and the second wicking layer 108 may be coupled, adhered, or welded along an exterior portion of each layer near the perimeter 122 of the first wicking layer and the perimeter 138 of the second wicking layer 108. The second side 120 of the first wicking layer 104 may face the first side 134 of the second wicking layer 108. The perimeter 122 of the first wicking layer may be coextensive with the perimeter 138 of the second wicking layer 108. [0047] In the example of FIG. 3, the first wicking layer 104 and the second wicking layer 108 are welded together by welds 310. The welds 310 are formed by heat sealing. The welds 310 may be formed along the entirety of the perimeter 122 and perimeter 138, or may be formed along a portion thereof. The welds 310 couple the first wicking layer 104 and the second wicking layer 108 such that an internal volume 312 is defined between the first wicking layer 104 and the second wicking layer 108.

[0048] The superabsorbent structure 106 may be disposed within the internal volume 312, as shown in FIG. 3. In some embodiments, at least a portion of the second side 132 of the superabsorbent structure 106 is in contact with at least a portion of the first side 134 of the second wicking layer 108. For example, substantially all of the second side 132 of the superabsorbent structure 106 may be in contact with substantially all of the first side 134 of the second wicking layer 108.

[0049] The foam layer 105 may be disposed within the internal volume 312, as shown in the example of FIG. 3. At least a portion of the second side 126 of the foam layer 105 may be in contact with at least a portion of the first side 130 of the superabsorbent structure 106. For example, substantially all of second side 126 of the foam layer 105 may be in contact with substantially all of the first side of the superabsorbent structure 106. At least a portion of the first side 124 of the foam layer 105 may be in contact with at least a portion of the second side 120 of the first wicking layer 104. For example, substantially all of the first side 124 of the foam layer 105 may be in contact with at substantially all of the second side 120 of the first wicking layer 104.

[0050] In some embodiments, the first wicking layer 104 may not be bonded or adhered to the foam layer 105. The foam layer 105 may not be bonded or adhered to the superabsorbent structure 106.

The superabsorbent structure 106 may not be bonded or adhered to the second wicking layer 108. The superabsorbent particles may be contained within the internal volume 312 by the first wicking layer 104, second wicking layer 108, and welds 310. Accordingly, the foam 105 and the superabsorbent structure 106 may be contained with the first wicking layer 104 and the second wicking layer 108 in a pouch-like or free-floating manner.

[0051] In some embodiments, the second wicking layer 108 is adhered or coupled to the wound contact layer 110. For example, a portion of the second side 136 of the second wicking layer 108 may be in contact with a portion of the first side 142 of the wound contact layer 110. For example, a portion of the second side 136 of the second wicking layer 108 may be in contact with a portion of the first side 142 of the wound contact layer 110. In some embodiments, the silicone adhesive of the wound contact layer 110 may cause the portion of the second side 136 of the second wicking layer 108 to adhere to the portion of the first side 142 of the wound contact layer 110.

[0052] As shown in FIG. 3, the second side 114 of the drape 102 is coated with an adhesive 314, for example an acrylic adhesive. A portion of the second side 114 of the drape 102 may be adhered to the first side 118 of the first wicking layer 104 by adhesive 314 A portion of the second side 114 of the drape 102 may be adhered to a portion of the first side 142 of the wound contact layer 110 by the adhesive 314. As illustrated in FIG. 3, the perimeter 116 of the drape 102 may be substantially coextensive with the perimeter 146 of the wound contact layer 110. The drape 102 may be thereby coupled to the wound contact layer 110 to define and exterior of the dressing 100.

[0053] FIG. 3 illustrates the dressing 100 applied to a wound 302. When applied to the wound 302, a portion of the wound contact layer 110 may adhere to epidermis 304, for example at the periwound area, within another portion of the wound contact layer 110 in contact with the wound 302. In a case where the wound 302 is emitting exudate or other wound or bodily fluids, the silicone adhesive of the wound contact layer 110 may reduce in tackiness at areas exposed to such fluid. The wound contact layer 110 may thereby be substantially prevented from adhering to the wound 302.

[0054] During application of the dressing 100 to the wound 302, moisture from the wound 302 is transported across the perforations 140 of the wound contact layer 110 and into contact with the second wicking layer 108. The second wicking layer 108 wicks fluid laterally along the second wicking layer 108, providing lateral distribution of the fluid across the dressing 100. The fluid is transported from the second wicking layer 108 to the superabsorbent structure 106. The fluid may also be transported from the second wicking layer 108 to the first wicking layer 104 at the portions where the first wicking layer 104 and the second wicking layer 108 are in contact near and at the welds 310.

[0055] The composite layer of the superabsorbent structure 106 absorbs and retains the fluid, for example swelling to store an amount of fluid greater than an original volume of the superabsorbent structure 106. Fluid may also be transported from the superabsorbent structure 106 to the foam layer 105, for example via open cells of the foam layer 105. The fluid is then transported from the foam layer 105 to the first wicking layer 104. The wicking layer 104 distributes fluid laterally along the first wicking layer 104, and transports fluid into contact with the drape 102. The drape is configured to allow moisture to evaporate therethrough from the first wicking layer 104 to an ambient environment to create an evaporative gradient from the superabsorbent structure 106 to the ambient environment. At portions where the wound contact layer 110 is adhered to the epidermis, moisture is transported across the perforations 140 in the wound contact layer 110 and across the drape 102, substantially reducing a risk of maceration. The dressing 100 is thereby configured to have an overall moisture vapor transfer rate that allows fluid from the wound to be moved away from the wound and out of the dressing 100 while providing an environment that supports wound healing.

[0056] In some embodiments, the construction of the dressing 100 shown in FIG. 3 provides a reduction in lateral shear forces. For example, a lateral force applied to the drape 102 may be transmitted to the first wicking layer 104 as a result of the adhesive bonds formed by adhesive layer 314. However, with a free-floating “tea-bag” arrangement where the first wicking layer 104 is not adhered to the foam layer 105, the lateral force may be reduced in transmission of the force from the first wicking layer 104 to the foam layer 105 (e.g., due to relative motion of the first wicking layer 104 and the foam layer 105). The force is further reduced by losses in transmission from the foam layer 105 to the superabsorbent structure 106, and from the superabsorbent structure 106 to the second wicking layer 108. Any lateral forces transferred through the dressing 100 to the wound contact layer 110 are thereby substantially reduced. Additionally, the reduced tackiness of the wound contact layer 110 on wet portions of the wound 302 further reduces lateral force transfer to the wound 302. This may improve comfort of the dressing 100 and protect the wound during healing.

[0057] Referring now to FIG. 4, a detailed cross-sectional schematic of the dressing 100 is shown, according to an exemplary embodiment. In particular, a cross-sectional view of the superabsorbent structure 106 is shown in detail as in some embodiments.

[0058] The superabsorbent structure 106 includes a first nonwoven layer 402 and a second nonwoven layer 406. The first nonwoven layer 402 may include a nonwoven textile material and may be configured to provide lateral wicking of fluid. The second nonwoven layer 406 may include a nonwoven textile material and may be configured to provide lateral wicking of fluid. The superabsorbent structure 106 also includes a first adhesive layer 404 disposed on a side of the first nonwoven layer 402 and a second adhesive layer 508 positioned on a side of the second nonwoven layer 406. The first adhesive layer 404 faces the second adhesive layer 408. The first adhesive layer 404 and the second adhesive layer 408 may include a PVA adhesive.

[0059] In the schematic of FIG. 4, a superabsorbent particle layer 410 is disposed between the first adhesive layer 404 and the second adhesive layer 408. For example, superabsorbent particles (e.g., sodium polyacrylate) may be sprayed, distributed, etc. on the first adhesive layer 404 and/or the second adhesive layer 408. The first nonwoven layer 402 and the second nonwoven layer 406 may then be brought together as shown in FIG. 4 to position the superabsorbent particle layer 410 between the first nonwoven layer 402 and the second nonwoven layer 406 and between the first adhesive layer 404 and the second adhesive layer 406. In other embodiments, the superabsorbent particles are positioned on the first nonwoven layer 402 and/or the second nonwoven layer 406 before the adhesive is applied. In other embodiments, the superabsorbent particles are mixed with the adhesive and then applied together to the first nonwoven layer 402 and the second nonwoven layer 406.

[0060] While the schematic of FIG. 4 shows discrete layers of nonwoven material, adhesive, and superabsorbent, the materials may be arranged and interspersed into a mixed composite layer. For example, the adhesive and the superabsorbent may become interspersed, mixed, etc. Also, the adhesive may penetrate the first nonwoven layer 402 and the second nonwoven layer 406. The result may be a composite layer (i.e., the superabsorbent structure 106) that includes the nonwoven material layers, the adhesives, and the superabsorbent particles. In some cases, the superabsorbent structure 106 as shown in FIG. 4 is substantially or partially rigid.

[0061] Referring now to FIG. 5, another detailed cross-sectional schematic of the dressing 100 is schematically shown, according to an exemplary embodiment In particular, a cross-sectional view of the superabsorbent structure 106 is shown in detail as in some embodiments. As above, FIG. 5 shows discrete layers for sake of illustration, while in some cases the first nonwoven layer 402, the first adhesive layer 404, the second nonwoven layer 406, the second adhesive layer 408, and/or the superabsorbent particle layer 410 may be intermixed, overlapping, etc. to form a composite. FIG. 5 shows the superabsorbent structure 106 having a first nonwoven layer 402, a first adhesive layer 404, a second nonwoven layer 406, a second adhesive layer 408, and a superabsorbent particle layer 410. [0062] In the embodiment of FIG. 5, the superabsorbent structure 106 is provided with a channel (hole, pathway, opening, fenestration, etc.) 614 extending therethrough. The channel 614 is configured to facilitate the flow of air and fluid across the superabsorbent structure 106. The channel 614 is defined by a border 700, with the border 700 formed by a combination of the first nonwoven layer 402, the first adhesive layer 404, the second nonwoven layer 406, the second adhesive layer 408, and the superabsorbent particle layer 410. The superabsorbent structure 160 of FIG. 5 may be particularly well-suited for use in a negative pressure wound therapy system as described below with reference to FIG. 6.

[0063] When a channel 614 is provided as in FIG. 5, the superabsorbent particles of the superabsorbent particle layer 410 may pose a risk of migrating from the superabsorbent structure 106 into the channel 614, and from there into undesirable areas of the dressing or wound therapy system (e.g., into a tube or pump). Accordingly, as described in detail below, a sealant (e.g., coating, film layers, glue, etc.) may be provided at least at the borders 700 to resist movement of the superabsorbent particles from the superabsorbent particle layer 410 and into the channel 614.

[0064] Referring now to FIG. 6, an embodiment of the dressing 100 adapted for use in negative pressure wound therapy (NPWT) is shown, according to an exemplary embodiment. In the example of FIG. 6, the dressing 100 is configured to provide for the communication of negative pressure (relative to ambient atmospheric pressure) to the wound 302. As in FIGS. 1-5, the dressing 100 of FIG. 6 includes the drape 102 coupled to the first wicking layer 104 by the adhesive layer 314, the hydrophilic foam layer 105 and superabsorbent structure 106 positioned between the second wicking layer 108 and the first wicking layer 104, and the wound contact layer 110 bonded to the drape 102 by the adhesive layer 314. In the embodiment of FIG. 6, the dressing 100 also includes additional features that facilitate airflow through the dressing 100 to provide for the communication of negative pressure to the wound 302 and which facilitate movement and storage of fluid away from the wound 302.

[0065] As shown in FIG. 6, the dressing 100 is configured to provide a sealed environment 602 in fluid communication with the wound 302. The drape 102 and the wound contact layer 110 are configured to be adhered (e.g., with a silicone adhesive of the wound contact layer 110) to the epidermis 304 at a periwound area such that the seal between the dressing 100 and the epidermis 304 is substantially airtight. In some embodiments, an additional adhesive (e.g., an acrylic adhesive) is provided at the periphery of the wound contact layer 110 to improve the seal between the dressing 100 and the epidermis 304 (e.g., to reduce leaks between the epidermis and the wound contact layer 110.

A sealed environment 602 is thereby established between the wound 302 and the drape 102. [0066] In the embodiment shown, the first wicking layer 104, the foam layer 105, the superabsorbent structure 106, and the second wicking layer 108 are contained in the sealed environment 602. In the example of FIG. 6, the dressing 100 also includes a manifold 604 positioned between the second wicking layer 108 and the wound contact layer 110 and in contact with the second wicking layer 108 and the wound contact layer 110. The manifold 604 is configured to allow air to flow therethrough vertically and laterally to facilitate substantially even distribution of negative pressure across the wound 302. The manifold 604 is also configured to provide for movement of fluid from the wound 302 to the second wicking layer 108 via the perforations 140 in the wound contact layer 110. For example, the manifold 604 may include an open-celled polyurethane foam.

[0067] The dressing 100 is also shown to include a port 606 formed through the drape 102 and a port 608 formed through the adhesive layer 314. The port 606 allows airflow through the drape 102 and the port 606 allows airflow through the adhesive layer 314. The ports 606, 608 are aligned to allow airflow through both the drape 102 and the adhesive layer 314 via the ports 606, 608. A connector 610 is coupled to the drape 102 at the port 606, such that the connector 610 is in fluid communication with the sealed environment 602 via the port 606 and the port 608.

[0068] The connector 610 is fluidly coupled to a negative-pressure source 612 via a conduit 616.

For example, the negative-pressure source 612 may include a pump configured to remove air and/or fluid from the sealed environment 602 via the port 606, the port 608, the connector 610, and the conduit 616. The conduit 616 may be a tube, for example having one or more bores defining one or more paths for fluid communication between the negative-pressure source 612 and the dressing 100. [0069] In the embodiments shown, an off-dressing fluid collector 650 is provided in fluid communication with the conduit 616. The off-dressing fluid collector 650 is configured to receive and store fluid removed from the dressing 100 via the tube 610. That is, in the embodiment shown, operation of the pump causes fluid to move from the wound 302, via the perforations 140 in the wound contact layer 110, across the manifold layer 604, through the channels 614 in the superabsorbent layer 106, across the foam layer 105, and into the conduit 616 via the connector 610 due to the pressure differential created by the negative-pressure source 612. The fluid can then be collected and stored at the off-dressing fluid collector 650. In some embodiments, the off-dressing fluid collector 650 is a canister (container, etc.) that includes an open volume that can fill with fluid and which, in some embodiments, may be emptied by a user when full. In some embodiments, the off-dressing fluid collector 650 is an absorbent material (e.g., superabsorbent polymer) provided in line along the conduit 616 and configured to absorb fluid flowing along the conduit 616. In such embodiments, the absorbent material may be arranged so as to not block airflow through the conduit 616 even when the absorbent material reaches its full absorption capacity. Other types of off-dressing fluid collectors are possible in various embodiments.

[0070] In the embodiment of FIG. 6, the superabsorbent structure 106 includes channels 614 that allow air and fluid to cross the superabsorbent structure 106 via the channels 614. For example, the superabsorbent structure 106 may be resistant to airflow therethrough, and may absorb and trap fluid that enters the superabsorbent structure 106. Accordingly, the channels 614 through the superabsorbent structure 106 provide for communication of negative pressure from the ports 606, 608 to the manifold 604 via the channels 614.

[0071] The channels 614 also provide for movement of fluid across the superabsorbent structure 106 from the wound 302 to the conduit 616 without the fluid being absorbed and trapped at the superabsorbent structure 106. The channels 614 can thereby allow for movement of fluid off of the dressing 100 via the conduit 616 while maintaining available absorption capacity in the superabsorbent structure 106. Accordingly, in some embodiments, the off-dressing fluid collector 650 acts as the primary fluid collection element, with the superabsorbent structure 106 provided as a back up for the off-dressing fluid collector 650 and/or to augment the capacity of the off-dressing fluid collector 650. For example, as described in detail below, the superabsorbent structure 106 may be provided with a sealant configured to at least partially prevent absorption of fluid at the superabsorbent structure 106 until the off-dressing fluid collector 650 is filled.

[0072] The dressing 100 of FIG. 6 is thereby configured for the transportation of air and fluid into, out of, and throughout the dressing 100. Fluid (e.g., liquid, wound exudate) moves from the wound 302 to the manifold 604 via perforations 140 in the wound contact layer 110. The manifold 604 is configured to allow fluid to move and distribute through the manifold 604 to the second wicking layer 108, which distributes fluid laterally across the dressing and to the superabsorbent structure 106. The superabsorbent structure 106 absorbs and stores fluid in the dressing (i.e., in the superabsorbent particle layer 410 shown in FIGS. 4-5), while fluid can also or alternatively be moved across the superabsorbent structure 106 via the channels 614. Fluid may move from the channels 614 (or from the superabsorbent structure 106) to the first wicking layer 104, which distributes the fluid along the drape 102 to facilitate evaporation of the fluid through the drape 102. In some embodiments, fluid is removed from the dressing 100 by the negative-pressure source 612 via the ports 606, 608 and the connector 610, for example to be collected at the off-dressing fluid collector 650. In other embodiments, the connector 610 and/or the ports 606, 608 is provided with a filter that allows air to be removed from the dressing but prevents fluid from entering the conduit 616, for example to protect the negative-pressure source 612 from exposure to wound exudate, and such that fluid storage is provided at the dressing 100 primarily by the superabsorbent structure 106.

[0073] Negative pressure is provided at the wound by allowing air to flow away from the wound 302 as follows. The perforations 140 in the wound contact layer 110 allow airflow from the wound 302 to the manifold 604. The manifold 604 allows airflow through the manifold in multiple directions, thereby allowing pressure to reach an approximately equal value throughout the manifold 604. Air can flow from the manifold 604 to the hydrophilic foam layer 105 via the channels 614 in the superabsorbent stmcture 106. The hydrophilic foam layer 105 may include an open-celled foam that allows from airflow therethrough and distribution of pressure across the foam layer 105. The first wicking layer 104 and the second wicking layer 108 may include a nonwoven textile that allows air to flow substantially freely across the first wicking layer 104 and the second wicking layer 108. The foam layer 105 is then in fluid communication with the ports 606, 608 which allow air to leave the sealed environment 602 via the connector 610 and the conduit 616. Negative pressure can thus be established at the wound 302 by operation of the negative pressure source 612.

[0074] Referring now to FIG. 7, a top view of the superabsorbent structure 106 having multiple channels 614 extending therethrough is shown, according to an exemplary embodiment. The superabsorbent structure 106 is a composite layer as described in detail above. In the example shown, the superabsorbent structure 106 has a width of approximately 10 cm and a length of approximately 10 cm, such that the superabsorbent structure 106 is approximately square-shaped. In other embodiments, the length and/or width dimensions are unequal such that the superabsorbent structure 106 is rectangular-shaped. In other embodiments, the superabsorbent structure 106 is round (e.g., a circle, an oval), polygonal (e.g., a triangle, a pentagon, etc.), or has some other regular or irregular shape.

[0075] The superabsorbent structure 106 includes multiple borders 700 that define the multiple channels 614, i.e., such that each channel 614 is defined by a border 700. Each border 700 can be made up of the each of the multiple components of the composite superabsorbent structure 106. For example, in the embodiment described above with reference to FIGS. 4-5, a first nonwoven layer 402, a first adhesive layer 404, a second nonwoven layer 406, a second adhesive layer 408, and a superabsorbent particle layer 410 of the superabsorbent structure 106 may all be exposed to the channels 614 at the borders 700.

[0076] Each channel 614 has dimensions such that air and fluid can flow therethrough, even when the superabsorbent particles of the superabsorbent structure 106 swell to absorb fluid. In the example shown, for example, each channel 614 is approximately circular with a diameter of approximately 10 millimeters. In various embodiments, the diameter of each channel 614 may be greater than 3 millimeters, for example in a range between approximately 5 millimeters and approximately 10 millimeters. The dimensions of the channels 614 can be selected to customize amounts of flow across the superabsorbent structure 106 and the rate or timing of absorption of fluid by the superabsorbent structure 106.

[0077] In the example shown, the channels 614 are circular, which maximizes a ratio between the area of a channel 614 and the perimeter defined by the corresponding border 700, thereby providing for maximal flow through the channels 614 while minimizing the exposed borders 700. In other embodiments, other shapes of the channels 614 may be used to achieve desired fluid handling properties for a dressing.

[0078] In the example shown, superabsorbent structure 106 includes sixteen channels 614 extending therethrough. The channels 614 are shown as arranged in an array (e.g., a four-by-four grid) and spaced approximately equidistantly across the superabsorbent structure 106. For example, each channel 614 may be separated from neighboring channels 614 by approximately 10 millimeters. Accordingly, in the example shown, a spacing between the channels 614 is approximately equal to a diameter of the channels 614. It follows that, in the example shown, the channels 614 occupy approximately 12.5% of the surface area of the superabsorbent structure 106.

[0079] In other examples, other numbers of channels 614 are included. For example, the number of channels 614 may be in a range between approximately 50 and approximately 25. In various embodiments, the channels may be arranged in a pattern suitable for achieving various fluid dynamic properties for the superabsorbent structure 106.

[0080] Referring now to FIG. 8, a top view of the superabsorbent structure 106 provided with a film seal 800 is shown, according to an exemplary embodiment. In the embodiment of FIG. 6, the superabsorbent structure 106 is provided with a first film layer on a first side 130 of the superabsorbent structure 106 and a second film layer on the second side 132 of the superabsorbent structure 106. The first film layer is fused to the second film layer to form the film seal 800. For example, the first film layer may be heat bonded to the second film layer around the periphery 130 of the superabsorbent structure 106 and within the plurality of channels 614 to form the film seal 800.

In some embodiments, the film layers are coupled together using an adhesive or a hot melt non-woven material. The superabsorbent structure 106 may thereby be laminated between the film layers.

[0081] In some embodiments, the film seal 800 is made of water soluble material(s), for example polyvinyl alcohol (PVOH) or polyvinyl pyrrolidone (PYP). In such embodiments, the film seal 800 may break down and dissolve when exposed to fluid, for example fluid exuded by a wound. In other embodiments, the film seal is made of water insoluble film matenal(s).

[0082] As shown in FIG. 8, the film seal 800 may be perforated at the channels 614 to allow air and fluid to flow therethrough. In the example shown, the film seal 800 includes a single perforation at each channel, with the perforation in the film seal 800 having a diameter slightly less than that of the channel 614. For example, the perforations may have diameters of approximately 7 millimeters in embodiments where the channels 614 have diameters of approximately 10 millimeters. In other examples, each film seal 800 may be provide with a multiple relatively small (e.g., 1 millimeter diameter, .5 millimeter diameter, etc.) perforations that allow air and fluid flow therethrough. The perforations in the film seal 800 may be created before or after lamination of the film seal 800 over the superabsorbent structure 106.

[0083] Referring now to FIG. 9, a flowchart of a process 900 for manufacturing a dressing that includes the superabsorbent structure 106 of FIG. 7 or a variation thereof is shown, according to an exemplary embodiment. The process 900 of FIG. 9 may be used to manufacture the dressing 100 of FIG 6, for example.

[0084] At step 902, a first substrate layer is provided. In some embodiments, the first substrate layer may be a first nonwoven layer 402 as described in detail above with reference to FIGS. 4-5. In other embodiments, the first substrate layer is a polyurethane film or other base. The first substrate layer to substantially prevent superabsorbent particles from passing through the first substrate layer (e.g., due to a size of the superabsorbent particles relative to a pore size of the first substrate layer). [0085] At step 904, a superabsorbent polymer is distributed on a first side of the first substrate layer. The superabsorbent polymer is formed as granules, for example such that a powder of the superabsorbent polymer can be distributed on the first side of the first substrate layer. In some embodiments, an adhesive is provided with the superabsorbent polymer or on the first substrate layer to facilitate the superabsorbent polymer in bonding to the first substrate layer.

[0086] At step 906, a composite layer (e.g., superabsorbent structure 106) is created by coupling a second substrate layer to the first side of the first substrate layer. The second substrate layer is positioned such that the superabsorbent polymer is between the first substrate layer and the second substrate layer. The second substrate layer may be a similar material as the first substrate layer. For example, the second substrate layer may be the second nonwoven layer 406 as described in detail above with reference to FIGS. 4-5. An adhesive may be included between the first substrate layer and the second substrate layer to couple the first substrate layer to the second substrate layer, thereby forming the composite layer. In some embodiments, additional materials are added and included in the composite layer.

[0087] At step 908, channels are created through the composite layer, i.e., through (at least) the first substrate layer, the second substrate layer, and the layer of superabsorbent polymer. For example, the channels can be cut with a blade or set of blades. In other embodiments, a laser or some other source of energy is used. The channels may be sized, shaped, and arranged as described above with reference to FIG. 7.

[0088] At step 910, the borders of the channels are sealed. FIG. 9 illustrates that several embodiments of step 910 are possible.

[0089] In some embodiments (step 912), a water-soluble coating is provided. The water-soluble coating may include a stabilizing material, for example sugar, sodium salt of carboxyymethyl cellulose, or a water-soluble polymer such as polyvinyl alcohol (PVOH), polyvinyl pyrrolidone (PVP), or polyethylene oxides (PEO). The superabsorbent structure 106 can be coated, printed, or sprayed with a solution containing the stabilizing material. For example, an organic solvent (e.g., ketones, alcohols) may be combined with PVP to form a solution which is applied to the superabsorbent structure 106, while allows the coating to be applied without causing absorption by the superabsorbent polymer. In some embodiments, the water-soluble coating is supplied approximately evenly across a full extend of the superabsorbent structure 106. In other embodiments, the providing the water-soluble coating includes aiming the water-soluble coating at the borders of the channel (e.g., printing the water-soluble coating on the superabsorbent structure 106 while avoiding exposure of remaining areas of the superabsorbent structure to the coating). In some embodiments, a registration or automated image recognition process is performed to automatically locate the channels and distribute the water-soluble coating accordingly. Although FIG. 9 illustrates performing step 912 after perforation at step 906, in other embodiments a water-soluble coating may before step 906. [0090] In some embodiments (step 914), a first film layer is sealed to a second film layer at the channels, such that the superabsorbent structure 106 is laminated between two film layers. For example, a film seal 800 may be formed as shown in FIG. 8 and described above with reference thereto. Step 914 can include perforating the film seal at the channels. The film may be water soluble or water insoluble in various embodiments.

[0091] In some embodiments (step 916), aglue or other adhesive is provided at the borders. The glue may seal the first substrate layer to the second substrate layer at the borders of the channels. The glue may be provided using a printing process and can be automatically aimed at the borders of the channels. In some variations, film rings are coupled to the superabsorbent structure 106 at the channels to seal the borders, while the film is not provided at remaining areas of the superabsorbent structure 106 as is the case in the embodiment of step 914.

[0092] Through these or other embodiments, the borders of the channels through the superabsorbent structure are thereby sealed at step 910. The sealant (e.g., abarrier applied according to the examples of steps 912-916) can then resist migration of superabsorbent particles out of the space between the substrate layers and into the channels. In embodiments where the sealant is water soluble, the sealant may break down over time to allow exposure of the superabsorbent to fluid after an initial time period. In embodiments where the sealant is applied only at the borders of the channels, fluid may be absorbed into the superabsorbent via remaining regions of the superabsorbent structure (e.g., by transfer across the first substrate layer). Parameters of the various materials and of the steps of process 900 can be selected and varied to customize the fluid handling properties of the superabsorbent structure.

[0093] At step 918, the composite layer is integrated into a dressing. For example, the composite layer may be coupled to and/or positioned within a pocket formed by an external drape layer and a wound contact layer. In some embodiments, the composite layer is combined with various other layers and materials to form a dressing consistent with the embodiments of FIGS. 1-6. The composite layer may be used in various specialty dressings. For example, the composite layer is provided in a dressing shaped to match an extremity of a patient (e.g., hand, foot, amputation stump). The dressing may also be coupled to or otherwise grouped with other components of a negative pressure wound therapy system at step 918 (e.g., conduit, off-dressing fluid collector, negative pressure source).

[0094] Referring now to FIG. 10, a flowchart of a process 1000 of fluid handling in the negative pressure wound therapy system of FIG. 6 is shown, according to an exemplary embodiment. Process 1000 can be initiated when the dressing 100 has been applied to a wound as shown in FIG. 6. The dressing 100 and the system of FIG. 6 may be configured to perform process 1000.

[0095] At step 1002, a pump (e.g., negative pressure source 612) operates to establish negative pressure (relative to atmospheric pressure) at the dressing 100. Step 1002 can involve removing air from the dressing 100. A pressure differential may draw fluid away from the wound and toward the negative pressure source 612.

[0096] At step 1004, due to a pressure differential created by the negative pressure source 612, fluid flows from the wound and through channels 614 of the composite layer (superabsorbent structure 106) to the conduit 616. Meanwhile, at step 1006, a sealant at the borders of the channels resists movement of the superabsorbent particles into the channel. The sealant also resists the flow of fluid to the superabsorbent particles. The channels and the sealant facilitate movement of fluid through the channels without substantial absorption by the superabsorbent particles and without movement of the superabsorbent particles into a position that could block fluid flow, either of which could block fluid flow in some scenarios.

[0097] At step 1008, the fluid that passes through the channels 614 and into the conduit (tube) 612 is collected at the off-dressing fluid collector 650. The off-dressing fluid collector 650 collects the fluid, for example retaining the fluid in a container and/or absorbing the fluid with an absorbent or superabsorbent material. Over time, the off-dressing fluid collector fluid fills to maximum capacity, as shown at step 1010. Meanwhile, the sealant at the channels breaks down due to fluid exposure at step 1012. In some embodiments, the sealant is configured to break down at a rate that corresponds to a capacity of the off-dressing fluid collector 650 or an expected duration before reaching capacity in step 1010. Breakdown of the sealant may be accelerated when the off-dressing fluid collector reaches maximum capacity and more fluid is caused to remain at the dressing 100.

[0098] When the off-dressing fluid collector is full in step 1010 and the sealant has broken down in step 1012, at step 1014 the superabsorbent polymer is exposed to fluid and absorbs fluid. Fluid is thereby absorbed and stored at the dressing 100. In such embodiments, the superabsorbent structure 106 of the dressing may act as a back-up to the off-dressmg fluid collector. The negative pressure wound therapy system has fluid handling capacity both on and off the dressing 100, which may lengthen the wear time of the dressing and/or increase the overall fluid capacity of the system.

[0099] Referring now to FIG. 11, an illustration of fluid absorption by the superabsorbent structure 106 is shown. In a first frame 1101, the superabsorbent structure 106 is provided with a volume of fluid. The first frame 1101 can be said to correspond to time zero. A second frame 1102 shows the superabsorbent structure 106 at a second time, for example shown as one minute after the first frame 1101. In the second frame 1102, absorption has begun but is resisted at least partially by a sealant on the superabsorbent structure 106. The sealant breaks down over time, and a third frame 1103 shows the superabsorbent structure 106 having absorbed a substantial amount of the fluid at a later time (shown as 14 minutes after fluid exposure in the first frame 1101). The third frame 1103 illustrates that, even when the superabsorbent structure 106 swells and absorbs fluid, the channels 614 remain open and fluid is allowed to flow through the channels 614 without being absorbed by the superabsorbent structure 106. Although particular times of the various frames are shown in FIG. 11, it should be understood that this experimental illustration is provided for example purposes and that other implementations with different parameters are possible.

[0100] In addition to the various embodiments described above, several other variations of the superabsorbent structure 106 are possible. For example, in some embodiments the superabsorbent polymer is printed as a slurry onto a substrate layer, for example a non-woven wicking layer. The slurry may include an adhesive to help bind the superabsorbent polymer to the non-woven wicking layer. The slurry can distributed in a patern that leaves areas of the substrate free of the slurry, for example such that channels are left through the superabsorbent slurry. Such channels can be arranged, shaped, and size as described above with reference to Fig. 7. The slurry may include water, alcohol (or water soluble organic solvent), and a water soluble polymer such as PVP or PVOH.

[0101] In some embodiments the slurry also includes a stabilizing filler polymer which is flow-able when heated. In such embodiments, the channels can be created by ultrasonic, radio-frequency, or heat perforation, which also causes the stabilizing filler polymer to seal the edges of the channels. In some cases, fusible polymer particles or fibers are added to the slurry, for example thermoplastic polyurethane, thermoplastic elastomer, polyvinylacetate, acrylic, PYOH copolymers, or PVP.

[0102] As another example, in some embodiments a fine non-woven layer is added around the superabsorbent structure 106 to form a “tea-bag” structure containing the superabsorbent structure.

The fine non-woven layer is provided with small enough pores to prevent the superabsorbent particles from escaping the tea-bag structure, while also allowing fluid flow into and out of the tea-bag structure. For example, in the embodiment of FIG. 6, the

[0103] As another example, in some embodiments a superabsorbent is provided as a fiber and mixed with a fusible fiber, for example as in a technical absorbent (TAL). The TAL fibers can be woven or knit into the desired perforated pattern (i.e., with channels extending therethrough), thereby forming the superabsorbent structure without a step of cuting the channels. This approach may reduce waste associated with cutting out channels from the superabsorbent structure 116.

[0104] In some embodiments, multiple superabsorbent structures can be used, for example arranged in a stack. In some cases, the channels in the multiple superabsorbent structures are aligned. In other embodiments in the multiple superabsorbent structures are offset (e.g., partially overlapping, not overlapping), for example to mediate the flow of fluid across the set of superabsorbent structures. Various combinations of multiple superabsorbent structures can be included to achieve desired fluid handling properties for a dressing.

[0105] The embodiments described above thereby provide a superabsorbent laminate with improved fluid and pressure manifolding and which can be used with an off-dressing fluid collection. Gel blocking of the superabsorbent structure may be prevented from disconnecting the wound from the negative pressure when the superabsorbent is full, and particles of superabsorbent may be prevented from migrating into the wound or into the tube. In some cases, the channels may increase the flexibility and conformability of the superabsorbent structure, and increase the surface area for absorbency into the superabsorbent structure. Furthermore, such properties are achieved, in some embodiments, without substantial reliance on difficult-to-control manufacturing parameters, thereby achieving consistent dressing performance even where multiple manufacturers are used. These and other advantages are achieved by the features disclosed herein.

[0106] As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims. [0107] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0108] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0109] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0110] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. All such variations are within the scope of the disclosure.