Patent Publication Number: US-2021162105-A1

Title: Dressing with differentially sized perforations

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/007,060, filed Jun. 13, 2018, which is a continuation of U.S. patent application Ser. No. 14/490,918, filed Sep. 19, 2014, now U.S. Pat. No. 10,016,544, which claims the benefit, under 35 USC § 119(e), of the filing of U.S. Provisional Patent Application Ser. No. 61/897,640, entitled “DRESSING WITH DIFFERENTIALLY SIZED PERFORATIONS,” filed Oct. 30, 2013, which are incorporated herein by reference for all purposes. 
    
    
     FIELD 
     This disclosure relates generally to medical treatment systems and, more particularly, but not by way of limitation, to absorbent dressings, systems, and methods for treating a tissue site with reduced pressure. 
     BACKGROUND 
     Depending on the medical circumstances, reduced pressure may be used for, among other things, reduced-pressure therapy to encourage granulation at a tissue site, draining fluids at a tissue site, closing a wound, reducing edema, promoting perfusion, and fluid management. Common dressings, systems, and methods may be susceptible to leaks and blockage that can cause a reduction in the efficiency of the therapy or a complete loss of therapy. Such a situation can occur, for example, if the amount of fluid in the dressing or system exceeds the fluid capacity of the dressing or system. Further, the formation of condensate in the dressing or system may create similar concerns. Leaks, blockages, and condensate in the dressing or system may also be perceptible by a user and may lack visual appeal. Prevention of leaks and blockages may be particularly important when only a limited power supply to the reduced pressure source and other components is available. Thus, improvements to dressings, systems, and methods that enhance the management of fluid extracted from a tissue site for increasing reliability, efficiency, visual appeal, and the useable life of the dressing and system are desirable. 
     SUMMARY 
     Shortcomings with certain aspects of tissue treatment dressings, systems, and methods are addressed as shown and described in a variety of illustrative, non-limiting embodiments herein. 
     In some embodiments, a system for treating a tissue site may include a tissue interface, a dressing, and a reduced-pressure source. The tissue interface may be adapted to be positioned proximate to the tissue site. The dressing may include a base layer, an adhesive, a sealing member, a first wicking layer, a second wicking layer, an absorbent layer, and a conduit interface. The base layer may have a periphery surrounding a central portion and a plurality of apertures disposed through the periphery and the central portion. The apertures in the periphery may be larger than the apertures in the central portion. Further, the base layer may be adapted to cover the tissue interface and tissue surrounding the tissue site. The adhesive may be in fluid communication with the apertures at least in the periphery of the base layer. The sealing member may have a periphery and a central portion. The periphery of the sealing member may be positioned proximate to the periphery of the base layer such that the central portion of the sealing member and the central portion of the base layer define an enclosure. The first wicking layer and the second wicking layer may each be disposed in the enclosure. The absorbent layer may be disposed between the first wicking layer and the second wicking layer. The conduit interface may be positioned proximate to the sealing member and in fluid communication with the enclosure. The reduced-pressure source may be adapted to be coupled in fluid communication with the conduit interface to provide reduced pressure to the dressing. 
     In other embodiments, a dressing for treating a tissue site may include a base layer, an adhesive, a sealing member, a first wicking layer, a second wicking layer, an absorbent layer, and a conduit interface. The base layer may have a periphery surrounding a central portion and a plurality of apertures disposed through the periphery and the central portion. The apertures in the periphery may be larger than the apertures in the central portion. The base layer may be adapted to cover the tissue site. The adhesive may be in fluid communication with the apertures in the base layer. The sealing member may have a periphery and a central portion. The periphery of the sealing member may be positioned proximate to the periphery of the base layer such that the central portion of the sealing member and the central portion of the base layer define an enclosure. The first wicking layer and the second wicking layer may each be disposed in the enclosure. The absorbent layer may be positioned in fluid communication between the first wicking layer and the second wicking layer. A peripheral portion of the first wicking layer may be coupled to a peripheral portion of the second wicking layer providing a wicking layer enclosure surrounding the absorbent layer between the first and the second wicking layer. The conduit interface may be positioned proximate to the sealing member and in fluid communication with the enclosure. 
     In other embodiments, a system for treating a tissue site may include a tissue interface, a dressing, and a reduced-pressure source. The tissue interface may be adapted to be positioned proximate to the tissue site and to distribute reduced pressure to the tissue site. The dressing may be adapted to provide reduced pressure to the tissue interface and to store fluid extracted from the tissue site through the tissue interface. The dressing may include a base layer, an adhesive, a sealing member, a first wicking layer, a second wicking layer, an absorbent layer, and a conduit interface. The base layer may have a periphery surrounding a central portion and a plurality of apertures disposed through the periphery and the central portion. The apertures in the periphery may be larger than the apertures in the central portion. The base layer may additionally include a border substantially surrounding the central portion and positioned between the central portion and the periphery. The border may be free of apertures. The central portion of the base layer may be adapted to be positioned proximate to the tissue interface and the periphery of the base layer may be adapted to be positioned proximate to tissue surrounding the tissue site. Further, the periphery of the base layer may be adapted to surround the tissue interface, and the apertures in the base layer may be adapted to be in fluid communication with the tissue interface and the tissue surrounding the tissue site. The adhesive may be in fluid communication with the apertures in the base layer. Further, the adhesive may be adapted to be in fluid communication with the tissue surrounding the tissue site through the apertures in the base layer. The sealing member may have a periphery and a central portion. The periphery of the sealing member may be positioned proximate to the periphery of the base layer such that the central portion of the sealing member and the central portion of the base layer define an enclosure. The first wicking layer and the second wicking layer may each be disposed in the enclosure. The absorbent layer may be positioned in fluid communication between the first wicking layer and the second wicking layer. The conduit interface may positioned proximate to the sealing member and in fluid communication with the enclosure. The reduced-pressure source may be adapted to be coupled in fluid communication with the conduit interface to provide reduced pressure to the dressing. 
     Other aspects, features, and advantages of the illustrative embodiments will become apparent with reference to the drawings and detailed description that follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cut-away view of an illustrative embodiment of a system for treating a tissue site depicting an illustrative embodiment of a dressing deployed at a tissue site; 
         FIG. 2  is a cut-away view of the dressing of  FIG. 1 ; 
         FIG. 3  is detail view taken at reference  FIG. 3 , depicted in  FIG. 1 , illustrating the dressing of  FIG. 1  positioned proximate to tissue surrounding the tissue site; 
         FIG. 4A  is an exploded view of the dressing of  FIG. 1 , depicted without a conduit interface and with an illustrative embodiment of a release liner for protecting the dressing prior to application at a tissue site; 
         FIG. 4B  is a plan view of an illustrative embodiment of a base layer depicted in the dressing of  FIG. 4A ; 
         FIG. 5  is a cut-away view of an illustrative embodiment of a fluid management assembly according to the dressing and system of  FIG. 1 ; 
         FIG. 6  is a cut-away view of another illustrative embodiment of a fluid management assembly according to the dressing and system of  FIG. 1 ; 
         FIG. 7  is a cut-away view of an illustrative embodiment of a conduit interface depicted in the dressing of  FIG. 1 ; 
         FIG. 8  is a cut-away view of another illustrative embodiment of a fluid management assembly suitable for use with the dressing and system of  FIG. 1 ; 
         FIG. 9A  is a cross-section of an illustrative embodiment of a multi-lumen conduit suitable for use with the dressing and system of  FIG. 1 ; 
         FIG. 9B  is a cross-section of another illustrative embodiment of a multi-lumen conduit suitable for use with the dressing and system of  FIG. 1 ; 
         FIG. 9C  is a cross-section of another illustrative embodiment of a multi-lumen conduit suitable for use with the dressing and system of  FIG. 1 ; 
         FIG. 9D  is a cross-section of another illustrative embodiment of a multi-lumen conduit suitable for use with the dressing and system of  FIG. 1 ; and 
         FIG. 9E  is a cross-section of another illustrative embodiment of a multi-lumen conduit suitable for use with the dressing and system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     In the following detailed description of non-limiting, illustrative embodiments, reference is made to the accompanying drawings that form a part hereof. Other embodiments may be utilized, and logical, structural, mechanical, electrical, and chemical changes may be made without departing from the scope of the appended claims. To avoid detail not necessary to enable those skilled in the art to practice the embodiments described herein, the description may omit certain information known to those skilled in the art. The following detailed description is non-limiting, and the scope of the illustrative embodiments are defined by the appended claims. As used herein, unless otherwise indicated, “or” does not require mutual exclusivity. 
     Referring to the drawings,  FIG. 1  depicts an embodiment of a system  102  for treating a tissue site  104  of a patient. The tissue site  104  may extend through or otherwise involve an epidermis  106 , a dermis  108 , and a subcutaneous tissue  110 . The tissue site  104  may be a sub-surface tissue site as depicted in  FIG. 1  that extends below the surface of the epidermis  106 . Further, the tissue site  104  may be a surface tissue site (not shown) that predominantly resides on the surface of the epidermis  106 , such as, for example, an incision. The system  102  may provide therapy to, for example, the epidermis  106 , the dermis  108 , and the subcutaneous tissue  110 , regardless of the positioning of the system  102  or the type of tissue site. The system  102  may also be utilized without limitation at other tissue sites. 
     Further, the tissue site  104  may be the bodily tissue of any human, animal, or other organism, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligaments, or any other tissue. Treatment of tissue site  104  may include removal of fluids, e.g., exudate or ascites. 
     Continuing with  FIG. 1 , the system  102  may include an optional tissue interface, such as an interface manifold  120 . Further, the system  102  may include a dressing  124 , and a reduced-pressure source  128 . The reduced-pressure source  128  may be a component of an optional therapy unit  130  as shown in  FIG. 1 . In some embodiments, the reduced-pressure source  128  and the therapy unit  130  may be separate components. As indicated above, the interface manifold  120  is an optional component that may be omitted for different types of tissue sites or different types of therapy using reduced pressure, such as, for example, epithelialization. If equipped, the interface manifold  120  may be adapted to be positioned proximate to or adjacent to the tissue site  104 , such as, for example, by cutting or otherwise shaping the interface manifold  120  in any suitable manner to fit the tissue site  104 . As described below, the interface manifold  120  may be adapted to be positioned in fluid communication with the tissue site  104  to distribute reduced pressure to the tissue site  104 . In some embodiments, the interface manifold  120  may be positioned in direct contact with the tissue site  104 . The tissue interface or the interface manifold  120  may be formed from any manifold material or flexible bolster material that provides a vacuum space, or treatment space, such as, for example, a porous and permeable foam or foam-like material, a member formed with pathways, a graft, or a gauze. As a more specific, non-limiting example, the interface manifold  120  may be a reticulated, open-cell polyurethane or polyether foam that allows good permeability of fluids while under a reduced pressure. One such foam material is the VAC® GranuFoam® material available from Kinetic Concepts, Inc. (KCI) of San Antonio, Tex. Any material or combination of materials may be used as a manifold material for the interface manifold  120  provided that the manifold material is operable to distribute or collect fluid. For example, herein the term manifold may refer to a substance or structure that is provided to assist in delivering fluids to or removing fluids from a tissue site through a plurality of pores, pathways, or flow channels. The plurality of pores, pathways, or flow channels may be interconnected to improve distribution of fluids provided to and removed from an area around the manifold. Examples of manifolds may include, without limitation, devices that have structural elements arranged to form flow channels, cellular foam, such as open-cell foam, porous tissue collections, and liquids, gels, and foams that include or cure to include flow channels. 
     A material with a higher or lower density than GranuFoam® material may be desirable for the interface manifold  120  depending on the application. Among the many possible materials, the following may be used: GranuFoam® material, Foamex® technical foam (www.foamex.com), a molded bed of nails structures, a patterned grid material such as those manufactured by Sercol Industrial Fabrics, 3D textiles such as those manufactured by Baltex of Derby, U.K., a gauze, a flexible channel-containing member, a graft, etc. In some instances, ionic silver may be added to the interface manifold  120  by, for example, a micro bonding process. Other substances, such as anti-microbial agents, may be added to the interface manifold  120  as well. 
     In some embodiments, the interface manifold  120  may comprise a porous, hydrophobic material. The hydrophobic characteristics of the interface manifold  120  may prevent the interface manifold  120  from directly absorbing fluid, such as exudate, from the tissue site  104 , but allow the fluid to pass through. 
     Continuing with  FIG. 1 , the dressing  124  may be adapted to provide reduced pressure from the reduced-pressure source  128  to the interface manifold  120 , and to store fluid extracted from the tissue site  104  through the interface manifold  120 . The dressing  124  may include a base layer  132 , an adhesive  136 , a sealing member  140 , a fluid management assembly  144 , and a conduit interface  148 . Components of the dressing  124  may be added or removed to suit a particular application. 
     Referring to  FIGS. 1-4B , the base layer  132  may have a periphery  152  surrounding a central portion  156 , and a plurality of apertures  160  disposed through the periphery  152  and the central portion  156 . The base layer  132  may also have corners  158  and edges  159 . The corners  158  and the edges  159  may be part of the periphery  152 . One of the edges  159  may meet another of the edges  159  to define one of the corners  158 . Further, the base layer  132  may have a border  161  substantially surrounding the central portion  156  and positioned between the central portion  156  and the periphery  152 . The border  161  may be free of the apertures  160 . The base layer  132  may cover the interface manifold  120  and tissue surrounding the tissue site  104  such that the central portion  156  of the base layer  132  is positioned adjacent to or proximate to the interface manifold  120 , and the periphery  152  of the base layer  132  is positioned adjacent to or proximate to tissue surrounding the tissue site  104 . In this manner, the periphery  152  of the base layer  132  may surround the interface manifold  120 . Further, the apertures  160  in the base layer  132  may be in fluid communication with the interface manifold  120  and tissue surrounding the tissue site  104 . 
     The apertures  160  in the base layer  132  may have any shape, such as, for example, circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, or other shapes. The apertures  160  may be formed by cutting, by application of local RF energy, or other suitable techniques for forming an opening. As shown in  FIGS. 4A-4B , each of the apertures  160  of the plurality of apertures  160  may be substantially circular in shape, having a diameter and an area. The area of each of the apertures  160  may refer to an open space or open area defining each of the apertures  160 . The diameter of each of the apertures  160  may define the area of each of the apertures  160 . For example, the area of one of the apertures  160  may be defined by multiplying the square of half the diameter of the aperture  160  by the value 3.14. Thus, the following equation may define the area of one of the apertures  160 : Area=3.14*(diameter/2){circumflex over ( )}2. The area of the apertures  160  described in the illustrative embodiments herein may be substantially similar to the area in other embodiments (not shown) for the apertures  160  that may have non-circular shapes. The diameter of each of the apertures  160  may be substantially the same, or each of the diameters may vary depending, for example, on the position of the aperture  160  in the base layer  132 . For example, the diameter of the apertures  160  in the periphery  152  of the base layer  132  may be larger than the diameter of the apertures  160  in the central portion  156  of the base layer  132 . Further, the diameter of each of the apertures  160  may be between about 1 millimeter to about 50 millimeters. In some embodiments, the diameter of each of the apertures  160  may be between about 1 millimeter to about 20 millimeters. The apertures  160  may have a uniform pattern or may be randomly distributed on the base layer  132 . The size and configuration of the apertures  160  may be designed to control the adherence of the dressing  124  to the epidermis  106  as described below. 
     Referring to  FIGS. 4A-4B , in some embodiments, the apertures  160  positioned in the periphery  152  may be apertures  160   a , the apertures  160  positioned at the corners  158  of the periphery  152  may be apertures  160   b , and the apertures  160  positioned in the central portion  156  may be apertures  160   c . The apertures  160   a  may have a diameter between about 9.8 millimeters to about 10.2 millimeters. The apertures  160   b  may have a diameter between about 7.75 millimeters to about 8.75 millimeters. The apertures  160   c  may have a diameter between about 1.8 millimeters to about 2.2 millimeters. The diameter of each of the apertures  160   a  may be separated from one another by a distance A between about 2.8 millimeters to about 3.2 millimeters. Further, the diameter of at least one of the apertures  160   a  may be separated from the diameter of at least one of the apertures  160   b  by the distance A. The diameter of each of the apertures  160   b  may also be separated from one another by the distance A. A center of one of the apertures  160   c  may be separated from a center of another of the apertures  160   c  in a first direction by a distance B between about 2.8 millimeters to about 3.2 millimeters. In a second direction transverse to the first direction, the center of one of the apertures  160   c  may be separated from the center of another of the apertures  160   c  by a distance C between about 2.8 millimeters to about 3.2 millimeters. As shown in  FIGS. 4A-4B , the distance B and the distance C may be increased for the apertures  160   c  in the central portion  156  being positioned proximate to or at the border  161  compared to the apertures  160   c  positioned away from the border  161 . 
     As shown in  FIGS. 4A-4B , the central portion  156  of the base layer  132  may be substantially square with each side of the central portion  156  having a length D between about 100 millimeters to about 108 millimeters. In some embodiments, the length D may be between about 106 millimeters to about 108 millimeters. The border  161  of the base layer  132  may have a width E between about 4 millimeters to about 11 millimeters and may substantially surround the central portion  156  and the apertures  160   c  in the central portion  156 . In some embodiments, the width E may be between about 9 millimeters to about 10 millimeters. The periphery  152  of the base layer  132  may have a width F between about 25 millimeters to about 35 millimeters and may substantially surround the border  161  and the central portion  156 . In some embodiments, the width F may be between about 26 millimeters to about 28 millimeters. Further, the periphery  152  may have a substantially square exterior with each side of the exterior having a length G between about 154 millimeters to about 200 millimeters. In some embodiments, the length G may be between about 176 millimeters to about 184 millimeters. Although  FIGS. 4A-4B  depict the central portion  156 , the border  161 , and the periphery  152  of the base layer  132  as having a substantially square shape, these and other components of the base layer  132  may have any shape to suit a particular application. Further, the dimensions of the base layer  132  as described herein may be increased or decreased, for example, substantially in proportion to one another to suit a particular application. The use of the dimensions in the proportions described above may enhance the cosmetic appearance of a tissue site. For example, these proportions may provide a surface area for the base layer  132 , regardless of shape, that is sufficiently smooth to enhance the movement and proliferation of epithelial cells at the tissue site  104 , and reduce the likelihood of granulation tissue in-growth into the dressing  124 . 
     The base layer  132  may be a soft, pliable material suitable for providing a fluid seal with the tissue site  104  as described herein. For example, the base layer  132  may comprise a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gels, a foamed gel, a soft closed cell foam such as polyurethanes and polyolefins coated with an adhesive described below, polyurethane, polyolefin, or hydrogenated styrenic copolymers. The base layer  132  may have a thickness between about 500 microns (μm) and about 1000 microns (μm). In some embodiments, the base layer  132  has a stiffness between about 5 Shore 00 and about 80 Shore 00. The base layer  132  may be comprised of hydrophobic or hydrophilic materials. 
     In some embodiments (not shown), the base layer  132  may be a hydrophobic-coated material. For example, the base layer  132  may be formed by coating a spaced material, such as, for example, woven, nonwoven, molded, or extruded mesh with a hydrophobic material. The hydrophobic material for the coating may be a soft silicone, for example. In this manner, the adhesive  136  may extend through openings in the spaced material analogous to the apertures  160  described below. 
     The adhesive  136  may be in fluid communication with the apertures  160  in at least the periphery  152  of the base layer  132 . In this manner, the adhesive  136  may be in fluid communication with the tissue surrounding the tissue site  104  through the apertures  160  in the base layer  132 . As described below and shown in  FIG. 3 , the adhesive  136  may extend or be pressed through the plurality of apertures  160  to contact the epidermis  106  for securing the dressing  124  to, for example, the tissue surrounding the tissue site  104 . The apertures  160  may provide sufficient contact of the adhesive  136  to the epidermis  106  to secure the dressing  124  about the tissue site  104 . However, the configuration of the apertures  160  and the adhesive  136 , described below, may permit release and repositioning of the dressing  124  about the tissue site  104 . 
     At least one of the apertures  160   a  in the periphery  152  of the base layer  132  may be positioned at the edges  159  of the periphery  152  and may have an interior cut open or exposed at the edges  159  that is in fluid communication in a lateral direction with the edges  159 . The lateral direction may refer to a direction toward the edges  159  and in the same plane as the base layer  132 . As shown in  FIGS. 4A-4B , a plurality of the apertures  160   a  in the periphery  152  may be positioned proximate to or at the edges  159  and in fluid communication in a lateral direction with the edges  159 . The apertures  160   a  positioned proximate to or at the edges  159  may be spaced substantially equidistant around the periphery  152  as shown in  FIGS. 4A-4B . However, in some embodiments, the spacing of the apertures  160   a  proximate to or at the edges  159  may be irregular. The adhesive  136  may be in fluid communication with the edges  159  through the apertures  160   a  being exposed at the edges  159 . In this manner, the apertures  160   a  at the edges  159  may permit the adhesive  136  to flow around the edges  159  for enhancing the adhesion of the edges  159  around the tissue site  104 , for example. 
     Continuing with  FIGS. 4A-4B , the apertures  160   b  at the corners  158  of the periphery  152  may be smaller than the apertures  160   a  in other portions of the periphery  152  as described above. For a given geometry of the corners  158 , the smaller size of the apertures  160   b  compared to the apertures  160   a  may maximize the surface area of the adhesive  136  exposed and in fluid communication through the apertures  160   b  at the corners  158 . For example, as shown in  FIGS. 4A-4B , the edges  159  may intersect at substantially a right angle, or about 90 degrees, to define the corners  158 . Also as shown, the corners  158  may have a radius of about 10 millimeters. Three of the apertures  160   b  having a diameter between about 7.75 millimeters to about 8.75 millimeters may be positioned in a triangular configuration at the corners  158  to maximize the exposed surface area for the adhesive  136 . The size and number of the apertures  160   b  in the corners  158  may be adjusted as necessary, depending on the chosen geometry of the corners  158 , to maximize the exposed surface area of the adhesive  136  as described above. Further, the apertures  160   b  at the corners  158  may be fully housed within the base layer  132 , substantially precluding fluid communication in a lateral direction exterior to the corners  158 . The apertures  160   b  at the corners  158  being fully housed within the base layer  132  may substantially preclude fluid communication of the adhesive  136  exterior to the corners  159 , and may provide improved handling of the dressing  124  during deployment at the tissue site  104 . Further, the exterior of the corners  158  being substantially free of the adhesive  136  may increase the flexibility of the corners  158  to enhance comfort. 
     Similar to the apertures  160   b  in the corners  158 , any of the apertures  160  may be adjusted in size and number to maximize the surface area of the adhesive  136  in fluid communication through the apertures  160  for a particular application or geometry of the base layer  132 . For example, in some embodiments (not shown) the apertures  160   b , or apertures of another size, may be positioned in the periphery  152  and at the border  161 . Similarly, the apertures  160   b , or apertures of another size, may be positioned as described above in other locations of the base layer  132  that may have a complex geometry or shape. 
     The adhesive  136  may be a medically-acceptable adhesive. The adhesive  136  may also be flowable. For example, the adhesive  136  may comprise an acrylic adhesive, rubber adhesive, high-tack silicone adhesive, polyurethane, or other adhesive substance. In some embodiments, the adhesive  136  may be a pressure-sensitive adhesive comprising an acrylic adhesive with coating weight of 15 grams/m 2  (gsm) to 70 grams/m 2  (gsm). The adhesive  136  may be a layer having substantially the same shape as the periphery  152  of the base layer  132  as shown in  FIG. 4A . In some embodiments, the layer of the adhesive  136  may be continuous or discontinuous. Discontinuities in the adhesive  136  may be provided by apertures (not shown) in the adhesive  136 . The apertures in the adhesive  136  may be formed after application of the adhesive  136  or by coating the adhesive  136  in patterns on a carrier layer, such as, for example, a side of the sealing member  140  adapted to face the epidermis  106 . Further, the apertures in the adhesive  136  may be sized to control the amount of the adhesive  136  extending through the apertures  160  in the base layer  132  to reach the epidermis  106 . The apertures in the adhesive  136  may also be sized to enhance the Moisture Vapor Transfer Rate (MVTR) of the dressing  124 , described further below. 
     Factors that may be utilized to control the adhesion strength of the dressing  124  may include the diameter and number of the apertures  160  in the base layer  132 , the thickness of the base layer  132 , the thickness and amount of the adhesive  136 , and the tackiness of the adhesive  136 . An increase in the amount of the adhesive  136  extending through the apertures  160  generally corresponds to an increase in the adhesion strength of the dressing  124 . A decrease in the thickness of the base layer  132  generally corresponds to an increase in the amount of adhesive  136  extending through the apertures  160 . Thus, the diameter and configuration of the apertures  160 , the thickness of the base layer  132 , and the amount and tackiness of the adhesive utilized may be varied to provide a desired adhesion strength for the dressing  124 . For example, the thickness of the base layer  132  may be about 200 microns, the adhesive layer  136  may have a thickness of about 30 microns and a tackiness of 2000 grams per 25 centimeter wide strip, and the diameter of the apertures  160   a  in the base layer  132  may be about 10 millimeters. 
     In some embodiments, the tackiness of the adhesive  136  may vary in different locations of the base layer  132 . For example, in locations of the base layer  132  where the apertures  160  are comparatively large, such as the apertures  160   a , the adhesive  136  may have a lower tackiness than other locations of the base layer  132  where the apertures  160  are smaller, such as the apertures  160   b  and  160   c . In this manner, locations of the base layer  132  having larger apertures  160  and lower tackiness adhesive  136  may have an adhesion strength comparable to locations having smaller apertures  160  and higher tackiness adhesive  136 . 
     Clinical studies have shown that the configuration described herein for the base layer  132  and the adhesive  136  may reduce the occurrence of blistering, erythema, and leakage when in use. Such a configuration may provide, for example, increased patient comfort and increased durability of the dressing  124 . 
     Referring to the embodiment of  FIG. 4B , a release liner  162  may be attached to or positioned adjacent to the base layer  132  to protect the adhesive  136  prior to application of the dressing  124  to the tissue site  104 . Prior to application of the dressing  124  to the tissue site  104 , the base layer  132  may be positioned between the sealing member  140  and the release liner  162 . Removal of the release liner  162  may expose the base layer  132  and the adhesive  136  for application of the dressing  124  to the tissue site  104 . The release liner  162  may also provide stiffness to assist with, for example, deployment of the dressing  124 . The release liner  162  may be, for example, a casting paper, a film, or polyethylene. Further, the release liner  162  may be a polyester material such as polyethylene terephthalate (PET), or similar polar semi-crystalline polymer. The use of a polar semi-crystalline polymer for the release liner  162  may substantially preclude wrinkling or other deformation of the dressing  124 . For example, the polar semi-crystalline polymer may be highly orientated and resistant to softening, swelling, or other deformation that may occur when brought into contact with components of the dressing  124 , or when subjected to temperature or environmental variations, or sterilization. Further, a release agent may be disposed on a side of the release liner  162  that is configured to contact the base layer  132 . For example, the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner  162  by hand and without damaging or deforming the dressing  124 . In some embodiments, the release agent may be flourosilicone. In other embodiments, the release liner  162  may be uncoated or otherwise used without a release agent. 
     Continuing with  FIGS. 1-4B , the sealing member  140  has a periphery  164  and a central portion  168 . The sealing member  140  may additionally include an aperture  170 , as described below. The periphery  164  of the sealing member  140  may be positioned proximate to the periphery  152  of the base layer  132  such that the central portion  168  of the sealing member  140  and the central portion  156  of the base layer  132  define an enclosure  172 . The adhesive  136  may be positioned at least between the periphery  164  of the sealing member  140  and the periphery  152  of the base layer  132 . The sealing member  140  may cover the tissue site  104  and the interface manifold  120  to provide a fluid seal and a sealed space  174  between the tissue site  104  and the sealing member  140  of the dressing  124 . Further, the sealing member  140  may cover other tissue, such as a portion of the epidermis  106 , surrounding the tissue site  104  to provide the fluid seal between the sealing member  140  and the tissue site  104 . In some embodiments, a portion of the periphery  164  of the sealing member  140  may extend beyond the periphery  152  of the base layer  132  and into direct contact with tissue surrounding the tissue site  104 . In other embodiments, the periphery  164  of the sealing member  140 , for example, may be positioned in contact with tissue surrounding the tissue site  104  to provide the sealed space  174  without the base layer  132 . Thus, the adhesive  136  may also be positioned at least between the periphery  164  of the sealing member  140  and tissue, such as the epidermis  106 , surrounding the tissue site  104 . The adhesive  136  may be disposed on a surface of the sealing member  140  adapted to face the tissue site  104  and the base layer  132 . 
     The sealing member  140  may be formed from any material that allows for a fluid seal. A fluid seal is a seal adequate to maintain reduced pressure at a desired site given the particular reduced pressure source or system involved. The sealing member  140  may comprise, for example, one or more of the following materials: hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; hydrophilic silicone elastomers; an INSPIRE  2301  material from Expopack Advanced Coatings of Wrexham, United Kingdom having, for example, an MVTR (inverted cup technique) of 14400 g/m 2 /24 hours and a thickness of about 30 microns; a thin, uncoated polymer drape; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; polyurethane (PU); EVA film; co-polyester; silicones; a silicone drape; a 3M Tegaderm® drape; a polyurethane (PU) drape such as one available from Avery Dennison Corporation of Pasadena, Calif.; polyether block polyamide copolymer (PEBAX), for example, from Arkema, France; Expopack 2327; or other appropriate material. 
     The sealing member  140  may be vapor permeable and liquid impermeable, thereby allowing vapor and inhibiting liquids from exiting the sealed space  174  provided by the dressing  124 . In some embodiments, the sealing member  140  may be a flexible, breathable film, membrane, or sheet having a high MVTR of, for example, at least about 300 g/m 2  per 24 hours. In other embodiments, a low or no vapor transfer drape might be used. The sealing member  140  may comprise a range of medically suitable films having a thickness between about 15 microns (μm) to about 50 microns (μm). 
     The fluid management assembly  144  may be disposed in the enclosure  172  and may include a first wicking layer  176 , a second wicking layer  180 , and an absorbent layer  184 . The absorbent layer  184  may be positioned in fluid communication between the first wicking layer  176  and the second wicking layer  180 . The first wicking layer  176  may have a grain structure (not shown) adapted to wick fluid along a surface of the first wicking layer  176 . Similarly, the second wicking layer  180  may have a grain structure (not shown) adapted to wick fluid along a surface of the second wicking layer  180 . For example, the first wicking layer  176  and the second wicking layer  180  may wick or otherwise transport fluid in a lateral direction along the surfaces of the first wicking layer  176  and the second wicking layer  180 , respectively. The surfaces of the first wicking layer  176  and the second wicking layer  180  may be normal relative to the thickness of each of the first wicking layer  176  and the second wicking layer  180 . The wicking of fluid along the first wicking layer  176  and the second wicking layer  180  may enhance the distribution of the fluid over a surface area of the absorbent layer  184  that may increase absorbent efficiency and resist fluid blockages. Fluid blockages may be caused by, for example, fluid pooling in a particular location in the absorbent layer  184  rather than being distributed more uniformly across the absorbent layer  184 . The laminate combination of the first wicking layer  176 , the second wicking layer  180 , and the absorbent layer  184  may be adapted as described above to maintain an open structure, resistant to blockage, capable of maintaining fluid communication with, for example, the tissue site  104 . 
     Referring to the embodiments of the fluid management assembly  144  depicted in  FIGS. 1, 2, 5, and 6 , a peripheral portion  186  of the first wicking layer  176  may be coupled to a peripheral portion  187  of the second wicking layer  180  to define a wicking layer enclosure  188  between the first wicking layer  176  and the second wicking layer  180 . In some exemplary embodiments, the wicking layer enclosure  188  may surround or otherwise encapsulate the absorbent layer  184  between the first wicking layer  176  and the second wicking layer  180 . 
     Referring specifically to  FIGS. 5 and 6 , the fluid management assembly  144  may include, without limitation, any number of wicking layers and absorbent layers as desired for treating a particular tissue site. For example, the absorbent layer  184  may be a plurality of absorbent layers  184  positioned in fluid communication between the first wicking layer  176  and the second wicking layer  180  as described above. Further, as depicted in  FIG. 6 , at least one intermediate wicking layer  189  may be disposed in fluid communication between the plurality of absorbent layers  184 . Similar to the absorbent layer  184  described above, the plurality of absorbent layers  184  and the at least one intermediate wicking layer  189  may be positioned within the wicking layer enclosure  188 . In some embodiments, the absorbent layer  184  may be disposed between the sealing member  140  and the interface manifold  120 , and the first wicking layer  176  and the second wicking layer  180  may be omitted. 
     In the embodiments of  FIGS. 5 and 6 , sides  184   a  of the absorbent layers  184  may remain in fluid communication with one another for enhancing efficiency. Similarly, in the embodiment of  FIG. 6 , sides  189   a  of the at least one intermediate wicking layer  189  may remain in fluid communication with one another and with the sides  184   a  of the absorbent layers  184 . Further, including additional absorbent layers  184  may increase the absorbent mass of the fluid management assembly  144  and generally provide greater fluid capacity. However, for a given absorbent mass, multiple light coat-weight absorbent layers  184  may be utilized rather than a single heavy coat-weight absorbent layer  184  to provide a greater absorbent surface area for further enhancing the absorbent efficiency. 
     In some embodiments, the absorbent layer  184  may be a hydrophilic material adapted to absorb fluid from, for example, the tissue site  104 . Materials suitable for the absorbent layer  184  may include Luquafleece® material, Texsus FP2326, BASF 402C, Technical Absorbents 2317 available from Technical Absorbents (www.techabsorbents.com), sodium polyacrylate super absorbers, cellulosics (carboxy methyl cellulose and salts such as sodium CMC), or alginates. Materials suitable for the first wicking layer  176  and the second wicking layer  180  may include any material having a grain structure capable of wicking fluid as described herein, such as, for example, Libeltex TDL2 80 gsm. 
     The fluid management assembly  144  may be a pre-laminated structure manufactured at a single location or individual layers of material stacked upon one another as described above. Individual layers of the fluid management assembly  144  may be bonded or otherwise secured to one another without adversely affecting fluid management by, for example, utilizing a solvent or non-solvent adhesive, or by thermal welding. Further, the fluid management assembly  144  may be coupled to the border  161  of the base layer  132  in any suitable manner, such as, for example, by a weld or an adhesive. The border  161  being free of the apertures  160  as described above may provide a flexible barrier between the fluid management assembly  144  and the tissue site  104  for enhancing comfort. 
     In some embodiments, the enclosure  172  defined by the base layer  132  and the sealing member  140  may include an anti-microbial layer  190 . The addition of the anti-microbial layer  190  may reduce the probability of excessive bacterial growth within the dressing  124  to permit the dressing  124  to remain in place for an extended period. The anti-microbial layer  190  may be, for example, an additional layer included as a part of the fluid management assembly  144  as depicted in  FIGS. 1 and 2 , or a coating of an anti-microbial agent disposed in any suitable location within the dressing  124 . The anti-microbial layer  190  may be comprised of elemental silver or similar compound, for example. In some embodiments, the anti-microbial agent may be formulated in any suitable manner into other components of the dressing  124 . 
     Referring to  FIGS. 1, 2, and 7 , the conduit interface  148  may be positioned proximate to the sealing member  140  and in fluid communication with the dressing  124  through the aperture  170  in the sealing member  140  to provide reduced pressure from the reduced-pressure source  128  to the dressing  124 . Specifically, the conduit interface  148  may be positioned in fluid communication with the enclosure  172  of the dressing  124 . The conduit interface  148  may also be positioned in fluid communication with the optional interface manifold  120 . As shown, an optional liquid trap  192  may be positioned in fluid communication between the dressing  124  and the reduced-pressure source  128 . The liquid trap  192  may be any suitable containment device having a sealed internal volume capable of retaining liquid, such as condensate or other liquids, as described below. 
     The conduit interface  148  may comprise a medical-grade, soft polymer or other pliable material. As non-limiting examples, the conduit interface  148  may be formed from polyurethane, polyethylene, polyvinyl chloride (PVC), fluorosilicone, or ethylene-propylene, etc. In some illustrative, non-limiting embodiments, conduit interface  148  may be molded from DEHP-free PVC. The conduit interface  148  may be formed in any suitable manner such as by molding, casting, machining, or extruding. Further, the conduit interface  148  may be formed as an integral unit or as individual components and may be coupled to the dressing  124  by, for example, adhesive or welding. 
     In some embodiments, the conduit interface  148  may be formed of an absorbent material having absorbent and evaporative properties. The absorbent material may be vapor permeable and liquid impermeable, thereby being configured to permit vapor to be absorbed into and evaporated from the material through permeation while inhibiting permeation of liquids. The absorbent material may be, for example, a hydrophilic polymer such as a hydrophilic polyurethane. Although the term hydrophilic polymer may be used in the illustrative embodiments that follow, any absorbent material having the properties described herein may be suitable for use in the system  102 . Further, the absorbent material or hydrophilic polymer may be suitable for use in various components of the system  102  as described herein. 
     The use of such a hydrophilic polymer for the conduit interface  148  may permit liquids in the conduit interface  148  to evaporate, or otherwise dissipate, during operation. For example, the hydrophilic polymer may allow the liquid to permeate or pass through the conduit interface  148  as vapor, in a gaseous phase, and evaporate into the atmosphere external to the conduit interface  148 . Such liquids may be, for example, condensate or other liquids. Condensate may form, for example, as a result of a decrease in temperature within the conduit interface  148 , or other components of the system  102 , relative to the temperature at the tissue site  104 . Removal or dissipation of liquids from the conduit interface  148  may increase visual appeal and prevent odor. Further, such removal of liquids may also increase efficiency and reliability by reducing blockages and other interference with the components of the system  102 . 
     Similar to the conduit interface  148 , the liquid trap  192 , and other components of the system  102  described herein, may also be formed of an absorbent material or a hydrophilic polymer. The absorptive and evaporative properties of the hydrophilic polymer may also facilitate removal and dissipation of liquids residing in the liquid trap  192 , and other components of the system  102 , by evaporation. Such evaporation may leave behind a substantially solid or gel-like waste. The substantially solid or gel-like waste may be cheaper to dispose than liquids, providing a cost savings for operation of the system  102 . The hydrophilic polymer may be used for other components in the system  102  where the management of liquids is beneficial. 
     In some embodiments, the absorbent material or hydrophilic polymer may have an absorbent capacity in a saturated state that is substantially equivalent to the mass of the hydrophilic polymer in an unsaturated state. The hydrophilic polymer may be fully saturated with vapor in the saturated state and substantially free of vapor in the unsaturated state. In both the saturated state and the unsaturated state, the hydrophilic polymer may retain substantially the same physical, mechanical, and structural properties. For example, the hydrophilic polymer may have a hardness in the unsaturated state that is substantially the same as a hardness of the hydrophilic polymer in the saturated state. The hydrophilic polymer and the components of the system  102  incorporating the hydrophilic polymer may also have a size that is substantially the same in both the unsaturated state and the saturated state. Further, the hydrophilic polymer may remain dry, cool to the touch, and pneumatically sealed in the saturated state and the unsaturated state. The hydrophilic polymer may also remain substantially the same color in the saturated state and the unsaturated state. In this manner, this hydrophilic polymer may retain sufficient strength and other physical properties to remain suitable for use in the system  102 . An example of such a hydrophilic polymer is offered under the trade name Techophilic HP-93A-100, available from The Lubrizol Corporation of Wickliffe, Ohio, United States. Techophilic HP-93A-100 is an absorbent hydrophilic thermoplastic polyurethane capable of absorbing 100% of the unsaturated mass of the polyurethane in water and having a durometer or Shore Hardness of about 83 Shore A. 
     The conduit interface  148  may carry an odor filter  194  adapted to substantially preclude the passage of odors from the tissue site  104  out of the sealed space  174 . Further, the conduit interface  148  may carry a primary hydrophobic filter  195  adapted to substantially preclude the passage of liquids out of the sealed space  174 . The odor filter  194  and the primary hydrophobic filter  195  may be disposed in the conduit interface  148  or other suitable location such that fluid communication between the reduced-pressure source  128 , or optional therapy unit  130 , and the dressing  124  is provided through the odor filter  194  and the primary hydrophobic filter  195 . In some embodiments, the odor filter  194  and the primary hydrophobic filter  195  may be secured within the conduit interface  148  in any suitable manner, such as by adhesive or welding. In other embodiments, the odor filter  194  and the primary hydrophobic filter  195  may be positioned in any exit location in the dressing  124  that is in fluid communication with the atmosphere, the reduced-pressure source  128 , or the optional therapy unit  130 . The odor filter  194  may also be positioned in any suitable location in the system  102  that is in fluid communication with the tissue site  104 . 
     The odor filter  194  may be comprised of a carbon material in the form of a layer or particulate. For example, the odor filter  194  may comprise a woven carbon cloth filter such as those manufactured by Chemviron Carbon, Ltd. of Lancashire, United Kingdom (www.chemvironcarbon.com). The primary hydrophobic filter  195  may be comprised of a material that is liquid impermeable and vapor permeable. For example, the primary hydrophobic filter  195  may comprise a material manufactured under the designation MMT-314 by W.L. Gore &amp; Associates, Inc. of Newark, Del., United States, or similar materials. The primary hydrophobic filter  195  may be provided in the form of a membrane or layer. 
     Continuing with  FIGS. 1, 2, and 7 , the reduced-pressure source  128  provides reduced pressure to the dressing  124  and the sealed space  174 . The reduced-pressure source  128  may be any suitable device for providing reduced pressure, such as, for example, a vacuum pump, wall suction, hand pump, or other source. As shown in  FIG. 1 , the reduced-pressure source  128  may be a component of the therapy unit  130 . The therapy unit  130  may include control circuitry and sensors, such as a pressure sensor, that may be configured to monitor reduced pressure at the tissue site  104 . The therapy unit  130  may also be configured to control the amount of reduced pressure from the reduced-pressure source  128  being applied to the tissue site  104  according to a user input and a reduced-pressure feedback signal received from the tissue site  104 . 
     As used herein, “reduced pressure” generally refers to a pressure less than the ambient pressure at a tissue site being subjected to treatment. Typically, this reduced pressure will be less than the atmospheric pressure. The reduced pressure may also be less than a hydrostatic pressure at a tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. While the amount and nature of reduced pressure applied to a tissue site will typically vary according to the application, the reduced pressure will typically be between −5 mm Hg and −500 mm Hg, and more typically in a therapeutic range between −100 mm Hg and −200 mm Hg. 
     The reduced pressure delivered may be constant or varied (patterned or random), and may be delivered continuously or intermittently. Although the terms “vacuum” and “negative pressure” may be used to describe the pressure applied to the tissue site, the actual pressure applied to the tissue site may be more than the pressure normally associated with a complete vacuum. Consistent with the use herein, an increase in reduced pressure or vacuum pressure typically refers to a relative reduction in absolute pressure. An increase in reduced pressure corresponds to a reduction in pressure (more negative relative to ambient pressure) and a decrease in reduced pressure corresponds to an increase in pressure (less negative relative to ambient pressure). 
     As shown in  FIG. 7 , a conduit  196  having an internal lumen  197  may be coupled in fluid communication between the reduced-pressure source  128  and the dressing  124 . The internal lumen  197  may have an internal diameter between about 0.5 millimeters to about 3.0 millimeters. More specifically, the internal diameter of the internal lumen  197  may be between about 1 millimeter to about 2 millimeters. The conduit interface  148  may be coupled in fluid communication with the dressing  124  and adapted to connect between the conduit  196  and the dressing  124  for providing fluid communication with the reduced-pressure source  128 . The conduit interface  148  may be fluidly coupled to the conduit  196  in any suitable manner, such as, for example, by an adhesive, solvent or non-solvent bonding, welding, or interference fit. The aperture  170  in the sealing member  140  may provide fluid communication between the dressing  124  and the conduit interface  148 . Specifically, the conduit interface  148  may be in fluid communication with the enclosure  172  or the sealed space  174  through the aperture  170  in the sealing member  140 . In some embodiments, the conduit  196  may be inserted into the dressing  124  through the aperture  170  in the sealing member  140  to provide fluid communication with the reduced-pressure source  128  without use of the conduit interface  148 . The reduced-pressure source  128  may also be directly coupled in fluid communication with the dressing  124  or the sealing member  140  without use of the conduit  196 . The conduit  196  may be, for example, a flexible polymer tube. A distal end of the conduit  196  may include a coupling  198  for attachment to the reduced-pressure source  128 . 
     The conduit  196  may have a secondary hydrophobic filter  199  disposed in the internal lumen  197  such that fluid communication between the reduced-pressure source  128  and the dressing  124  is provided through the secondary hydrophobic filter  199 . The secondary hydrophobic filter  199  may be, for example, a porous, sintered polymer cylinder sized to fit the dimensions of the internal lumen  197  to substantially preclude liquid from bypassing the cylinder. The secondary hydrophobic filter  199  may also be treated with an absorbent material adapted to swell when brought into contact with liquid to block the flow of the liquid. The secondary hydrophobic filter  199  may be positioned at any location within the internal lumen  197 . However, positioning the secondary hydrophobic filter  199  within the internal lumen  197  closer toward the reduced-pressure source  128 , rather than the dressing  124 , may allow a user to detect the presence of liquid in the internal lumen  197 . 
     In some embodiments, the conduit  196  and the coupling  198  may be formed of an absorbent material or a hydrophilic polymer as described above for the conduit interface  148 . In this manner, the conduit  196  and the coupling  198  may permit liquids in the conduit  196  and the coupling  198  to evaporate, or otherwise dissipate, as described above for the conduit interface  148 . The conduit  196  and the coupling  198  may be, for example, molded from the hydrophilic polymer separately, as individual components, or together as an integral component. Further, a wall of the conduit  196  defining the internal lumen  197  may be extruded from the hydrophilic polymer. The conduit  196  may be less than about 1 meter in length, but may have any length to suit a particular application. More specifically, a length of about 1 foot or 304.8 millimeters may provide enough absorbent and evaporative surface area to suit many applications, and may provide a cost savings compared to longer lengths. If an application requires additional length for the conduit  196 , the absorbent hydrophilic polymer may be coupled in fluid communication with a length of conduit formed of a non-absorbent hydrophobic polymer to provide additional cost savings. 
     Referring now to  FIG. 8 ,  FIG. 8  depicts the dressing  124  including a fluid management assembly  244  suitable for use with the dressing  124  and the system  102 . The fluid management assembly  244  may include a first wicking layer  276 , a second wicking layer  280 , and an absorbent layer  284  comprised of substantially the same materials and properties as those described above in connection with the fluid management assembly  144 . Thus, the first wicking layer  276 , the second wicking layer  280 , and the absorbent layer  284  are analogous to the first wicking layer  176 , the second wicking layer  180 , and the absorbent layer  184 , respectively. 
     In the fluid management assembly  244 , the second wicking layer  280  may have a peripheral portion  287 . The second wicking layer  280  and the peripheral portion  287  of the second wicking layer  280  may be positioned in contact with the sealing member  140 . The absorbent layer  284  may have a peripheral portion  285  extending beyond the peripheral portion  287  of the second wicking layer  280 . The absorbent layer  284  may be positioned adjacent to or proximate to the second wicking layer  280  such that the peripheral portion  285  of the absorbent layer  284  is in contact with the sealing member  140  surrounding the peripheral portion  287  of the second wicking layer  280 . Similarly, the first wicking layer  276  may have a peripheral portion  286  extending beyond the peripheral portion  285  of the absorbent layer  284 . The first wicking layer  276  may be positioned adjacent to or proximate to the absorbent layer  284  such that the peripheral portion  286  of the first wicking layer  276  is in contact with the sealing member  140  surrounding the peripheral portion  285  of the absorbent layer  284 . Further, the first wicking layer  276  may be positioned adjacent to or proximate to the base layer  132 . Thus, at least the peripheral portion  287 , the peripheral portion  285 , and the peripheral portion  286  in contact with the sealing member  140  may be coupled to the sealing member  140 , such as, for example, by an adhesive coating disposed on a surface of the sealing member  140  facing the base layer  132 . The adhesive coating may be analogous to the adhesive  136  being applied across the surface of the sealing member  140  facing the base layer  132 . The second wicking layer  280 , the absorbent layer  284 , and the first wicking layer  276  may respectively have increasing surface areas to enhance contact with the adhesive coating described above. In other embodiments, the fluid management assembly  244  may include any number of absorbent layers and wicking layers for treating a particular tissue site. 
     In operation of the system  102  according to some illustrative embodiments, the interface manifold  120  may be disposed against or proximate to the tissue site  104 . The dressing  124  may then be applied over the interface manifold  120  and the tissue site  104  to form the sealed space  174 . Specifically, the base layer  132  may be applied covering the interface manifold  120  and the tissue surrounding the tissue site  104 . The materials described above for the base layer  132  have a tackiness that may hold the dressing  124  initially in position. The tackiness may be such that if an adjustment is desired, the dressing  124  may be removed and reapplied. Once the dressing  124  is in the desired position, a force may be applied, such as by hand pressing, on a side of the sealing member  140  opposite the tissue site  104 . The force applied to the sealing member  140  may cause at least some portion of the adhesive  136  to penetrate or extend through the plurality of apertures  160  and into contact with tissue surrounding the tissue site  104 , such as the epidermis  106 , to releaseably adhere the dressing  124  about the tissue site  104 . In this manner, the configuration of the dressing  124  described above may provide an effective and reliable seal against challenging anatomical surfaces, such as an elbow or heal, at and around the tissue site  104 . Further, the dressing  124  permits re-application or re-positioning to, for example, correct air leaks caused by creases and other discontinuities in the dressing  124  and the tissue site  104 . The ability to rectify leaks may increase the reliability of the therapy and reduce power consumption. 
     As the dressing  124  comes into contact with fluid from the tissue site  104 , the fluid moves through the apertures  160  toward the fluid management assembly  144 ,  244 . The fluid management assembly  144 ,  244  wicks or otherwise moves the fluid through the interface manifold  120  and away from the tissue site  104 . As described above, the interface manifold  120  may be adapted to communicate fluid from the tissue site  104  rather than store the fluid. Thus, the fluid management assembly  144 ,  244  may be more absorbent than the interface manifold  120 . The fluid management assembly  144 ,  244  being more absorbent than the interface manifold  120  provides an absorbent gradient through the dressing  124  that attracts fluid from the tissue site  104  or the interface manifold  120  to the fluid management assembly  144 ,  244 . Thus, in some embodiments, the fluid management assembly  144 ,  244  may be adapted to wick, pull, draw, or otherwise attract fluid from the tissue site  104  through the interface manifold  120 . In the fluid management assembly  144 ,  244 , the fluid initially comes into contact with the first wicking layer  176 ,  276 . The first wicking layer  176 ,  276  may distribute the fluid laterally along the surface of the first wicking layer  176 ,  276  as described above for absorption and storage within the absorbent layer  184 ,  284 . Similarly, fluid coming into contact with the second wicking layer  180 ,  280  may be distributed laterally along the surface of the second wicking layer  180 ,  280  for absorption within the absorbent layer  184 ,  284 . 
     Referring to  FIGS. 9A-9E , in other embodiments, the conduit  196  may be a multi-lumen conduit  302 . For example,  FIG. 9A  depicts an illustrative embodiment of a multi-lumen conduit  302   a . The multi-lumen conduit  302   a  may have an external surface  306 , a primary lumen  310 , a wall  314 , and at least one secondary lumen  318 . The wall  314  may carry the primary lumen  310  and the at least one secondary lumen  318 . The primary lumen  310  may be substantially isolated from fluid communication with the at least one secondary lumen  318  along the length of the multi-lumen conduit  302   a . Although shown in  FIG. 9A  as having a substantially circular cross-section, the external surface  306  of the multi-lumen conduit  302   a  may have any shape to suit a particular application. The wall  314  of the multi-lumen conduit  302   a  may have a thickness between the primary lumen  310  and the external surface  306 . As depicted in  FIG. 9A , the at least one secondary lumen  318  may be four secondary lumens  318  carried by the wall  314  substantially parallel to the primary lumen  310  and about a perimeter of the primary lumen  310 . The secondary lumens  318  may be separate from one another and substantially isolated from fluid communication with one another along the length of the multi-lumen conduit  302   a . Further, the secondary lumens  318  may be separate from the primary lumen  310  and substantially isolated from fluid communication with the primary lumen  310 . The secondary lumens  318  may also be positioned concentric relative to the primary lumen  310  and substantially equidistant about the perimeter of the primary lumen  310 . Although  FIG. 9A  depicts four secondary lumens  318 , any number of secondary lumens  318  may be provided and positioned in any suitable manner for a particular application. 
     Similar to the internal lumen  197  of the conduit  196 , the primary lumen  310  may be coupled in fluid communication between the reduced-pressure source  128  and the dressing  124  as described above. In some embodiments, the primary lumen  310  may be coupled in fluid communication between the conduit interface  148  and the reduced-pressure source  128 . Further, analogous to the internal lumen  197 , reduced pressure may be provided through the primary lumen  310  from the reduced-pressure source  128  to the dressing  124 . In some embodiments, the primary lumen  310  may be configured to extract fluid such as exudate from the tissue site  104 . The secondary lumens  318  may be coupled in fluid communication between the therapy unit  130  and the dressing  124 . In some embodiments, the at least one secondary lumen  318  may be coupled in fluid communication between the conduit interface  148  and the therapy unit  130 . Further, the secondary lumens  318  may be in fluid communication with the primary lumen  310  at the dressing  124  and configured to provide a reduced-pressure feedback signal from the dressing  124  to the therapy unit  130 . For example, the secondary lumens  318  may be in fluid communication with the primary lumen  310  at the conduit interface  148  or other component of the dressing  124 . 
     The multi-lumen conduit  302   a  may be comprised of an absorbent material or hydrophilic polymer, such as, for example, the absorbent material or the hydrophilic polymer described above in connection with the conduit interface  148 , the conduit  196 , and the coupling  198 . The absorbent material or the hydrophilic polymer may be vapor permeable and liquid impermeable. In some embodiments, at least a portion of the wall  314  and the external surface  306  of the multi-lumen conduit  302   a  may be comprised of the absorbent material or the hydrophilic polymer. In this manner, the multi-lumen conduit  302   a  may permit liquids, such as condensate, in the multi-lumen conduit  302   a  to evaporate, or otherwise dissipate, as described above. For example, the absorbent material or the hydrophilic polymer may allow the liquid to pass through the multi-lumen conduit  302   a  as vapor, in a gaseous phase, and evaporate into the atmosphere external to the multi-lumen conduit  302   a . Liquids such as exudate from the tissue site  104  may also be evaporated or dissipated through the multi-lumen conduit  302   a  in the same manner. This feature may be advantageous when the optional therapy unit  130  is used for monitoring and controlling reduced pressure at the tissue site  104 . For example, liquid present in the secondary lumens  318  may interfere with a reduced-pressure feedback signal being transmitted to the therapy unit  130  through the secondary lumens  318 . The use of the hydrophilic polymer for the multi-lumen conduit  302   a  may permit removal of such liquid for enhancing the visual appeal, reliability, and efficiency of the system  102 . After evaporation of liquid in the multi-lumen conduit  302   a , other blockages from, for example, desiccated exudate, solids, or gel-like substances that were carried by the evaporated liquid may be visible for further remediation. Further, the use of the hydrophilic polymer as described herein may reduce the occurrence of skin damage caused by moisture buildup between components of the system  102 , such as the multi-lumen conduit  302   a , and the skin of a patient. 
     Depicted in  FIG. 9B  is another illustrative embodiment of a multi-lumen conduit  302   b . Similar to the multi-lumen conduit  302   a , the multi-lumen conduit  302   b  may have the external surface  306 , the primary lumen  310 , the wall  314 , and the at least one secondary lumen  318  as described above. However, the wall  314  of the multi-lumen conduit  302   b  may include a first wall material  314   a  and a second wall material  314   b . The first wall material  314   a  and the second wall material  314   b  may be comprised of different materials to form the wall  314 . For example, the first wall material  314   a  may comprise a substantially non-absorbent hydrophobic polymer, or other material, that is vapor impermeable and liquid impermeable. The first wall material  314   a  may completely surround the primary lumen  310 , defining the primary lumen  310  as shown in  FIG. 9B . In some embodiments (not shown), the first wall material  314   a  may be positioned around the primary lumen  310  without completely surrounding or defining the primary lumen  310 . The second wall material  314   b  may comprise the same absorbent material or hydrophilic polymer described above for the multi-lumen conduit  302   a  as being vapor permeable and liquid impermeable. As shown in  FIG. 9B , the second wall material  314   b  may be positioned in fluid contact with the at least one secondary lumen  318 . The second wall material  314   b  may also define the at least one secondary lumen  318  and at least a portion of the external surface  306  of the multi-lumen conduit  302   b . In some embodiments (not shown), the second wall material  314   b  may substantially surround the at least one secondary lumen  318  without completely defining the secondary lumen  318 . 
     Continuing with  FIG. 9B , the first wall material  314   a  may be substantially concentric about the primary lumen  310 , and the second wall material  314   b  may be substantially concentric about and contiguous with the first wall material  314   a . The first wall material  314   a  and the second wall material  314   b  may be molded, co-extruded, or otherwise combined with one another in any suitable manner to form the wall  314 . The wall  314 , including the first wall material  314   a  and the second wall material  314   b , may provide a cost savings while retaining the absorbent and evaporative properties of the hydrophilic polymer for remediating liquid in the multi-lumen conduit  302   b  and the at least one secondary lumen  318 . Further, the use of the first wall material  314   a  as described herein may provide sufficient strength and other physical properties for the multi-lumen conduit  302   b  to remain serviceable under reduced pressure in the system  102  without regard to the physical properties of second wall material  314   b . For example, the use of a non-absorbent hydrophobic polymer for the first wall material  314   a  may permit the use of absorbent hydrophilic polymers for the second wall material  314   b  that may not otherwise have sufficient strength for use under reduced pressure in the system  102 . 
     The first wall material  314   a  may be combined with the second wall material  314   b  to form the wall  314  in various configurations for remediating liquid in the multi-lumen conduit  302  and the at least one secondary lumen  318 . For example, referring to  FIG. 9C , depicted is an illustrative embodiment of a multi-lumen conduit  302   c . Similar to the multi-lumen conduits  302   a  and  302   b , the multi-lumen conduit  302   c  may have the external surface  306 , the primary lumen  310 , the wall  314 , and the at least one secondary lumen  318 . As shown in  FIG. 9C , the wall  314  of the multi-lumen conduit  302   c  may include the first wall material  314   a  positioned around the primary lumen  310  and the second wall material  314   b  disposed in separate portions around each of the secondary lumens  318 . In this configuration, for example, the external surface  306  may comprise both the first wall material  314   a  and the second wall material  314   b . Also as shown in  FIG. 9C , the first wall material  314   a  may completely surround the primary lumen  310 . The second wall material  314   b  may be disposed as portions separate from one another and separate from the primary lumen in a radial configuration about the perimeter of the primary lumen  310 . However, in some embodiments, the second wall material  314   b  may be in fluid contact with the primary lumen  310  and may form a portion of the external surface  306 . The amount of the second wall material  314   b  surrounding the secondary lumens  318  may be increased or decreased to suit a particular application depending, for example, on the amount of liquid anticipated to be present and the desired mechanical properties of the multi-lumen conduit  302   c.    
     Continuing with  FIG. 9C , the first wall material  314   a  may have a receptor  320  configured to receive the second wall material  314   b . The second wall material  314   b  surrounding the secondary lumens  318  may have a shape corresponding to the receptor  320  in the first wall material  314   a . For example, each portion of the second wall material  314   b  may have a taper  321   a  configured to engage a corresponding taper  321   b  of the receptor  320 . The taper  321   b  may be oriented opposite the taper  321   a . As shown in  FIG. 9C , the taper  321   b  of the receptor  320  may taper from the external surface  306  to a smaller dimension toward the primary lumen  310 . The taper  321   a  may have a taper opposite the direction of the taper  321   b  described above such that the taper  321   b  is configured to receive and engage the taper  321   a.    
     In some embodiments (not shown), the taper  321   a  of the second wall material  314   b  may taper from the external surface  306  to a larger dimension toward the primary lumen  310 . The taper  321   b  of the receptor  320  may have a taper opposite the direction of the taper  321   a  described above such that the taper  321   b  is configured to receive and engage the taper  321   a . In this configuration, with the taper  321   a  of the second wall material  314   b  having a larger dimension toward the primary lumen  310 , the opposite taper  321   b  of the receptor  320  may substantially preclude the second wall material  314   b  from being pulled away from the receptor  320  in the first wall material  314   a . The above embodiments for the tapers  321   a  and  321   b  are non-limiting. Other shapes and configurations are suitable for engaging the first wall material  314   a  with the second wall material  314   b , such as, for example, interlocking tabs or other mechanical elements. 
     The multi-lumen conduit  302  may include other materials and configurations for managing liquid in the multi-lumen conduit  302  as described herein. For example, referring to  FIG. 9D , depicted is an illustrative embodiment of a multi-lumen conduit  302   d . Similar to the multi-lumen conduits  302   a ,  302   b , and  302   c , the multi-lumen conduit  302   d  may have the external surface  306 , the primary lumen  310 , the wall  314 , and the at least one secondary lumen  318 . The multi-lumen conduit  302   d  may additionally include an external absorbent layer  322 . The external absorbent layer  322  may be positioned around the wall  314  of the multi-lumen conduit  302   d . The external absorbent layer  322  may be positioned, for example, along the entire length of the multi-lumen conduit  302   d  or a portion of the length of the multi-lumen conduit  302   d . More specifically, the external absorbent layer  322  may be positioned on a portion of the length of the multi-lumen conduit  302   d  proximate to the dressing  124 . 
     Continuing with  FIG. 9D , the wall  314  of the multi-lumen conduit  302   d  may comprise an absorbent material or a hydrophilic polymer, such as the absorbent material or the hydrophilic polymer described above for the multi-lumen conduit  302   a  as being vapor permeable and liquid impermeable. Although not shown in  FIG. 9D , the wall  314  of the multi-lumen conduit  302   d  may include the first wall material  314   a  and the second wall material  314   b  as described above for  FIGS. 9B and 9C . The external absorbent layer  322  may be comprised, for example, of the same absorbent material or hydrophilic polymer of the wall  314 . In some embodiments, the external absorbent layer  322  may be comprised of a second absorbent material or a second hydrophilic polymer that is vapor permeable and liquid impermeable. The second absorbent material may have a greater absorbent capacity than the absorbent material or hydrophilic polymer comprising the wall  314  or the second wall material  314   b . For example, the second absorbent material of the external absorbent layer  322  may be capable of absorbing more than 100% of the unsaturated mass of the second absorbent material in water. In this manner, the external absorbent layer  322  may be configured to provide an absorptive gradient increasing in absorbent capacity away from the primary lumen  310  and toward the external surface  306 . The absorptive gradient may pull, wick, draw, or otherwise attract vapor toward the external surface  306  for evaporation. In some embodiments, the thickness of the wall  314  may be reduced to enhance the passage or permeation of vapor through the wall  314  and to the external atmosphere. In embodiments (not shown) including the first wall material  314   a  and the second wall material  314   b , the external absorbent layer  322  may be positioned at least around the second wall material  314   b  and in fluid contact with the second wall material  314   b.    
     Continuing with  FIG. 9D , the external surface  306  of the multi-lumen conduit  302   d  may have any shape to suit a particular application. For example, the external surface  306  may have a plurality of protrusions  326  and depressions  330  configured to increase the external surface area of the external surface  306 . The increased surface area provided by the protrusions  326  and depressions  330  may enhance the ability of the multi-lumen conduit  302   d  to evaporate liquids. 
     Referring to  FIG. 9E , depicted is an illustrative embodiment of a multi-lumen conduit  302   e  having an oblong cross section. Similar to the multi-lumen conduits  302   a ,  302   b ,  302   c , and  302   d , the multi-lumen conduit  302   e  may have the external surface  306 , the primary lumen  310 , the wall  314 , and the at least one secondary lumen  318 . However,  FIG. 9E  depicts the at least one secondary lumen  318  of the multi-lumen conduit  302   e  as a single secondary lumen  318  that may be carried by the wall  314  beside the primary lumen  310 . Such a configuration may provide a substantially flat, low profile shape that may enhance user comfort and may increase the flexibility of the multi-lumen conduit  302   e . For example, in this configuration, the multi-lumen conduit  302   e  may be routed through tight spaces with reduced risk of kinking or blockages of fluid communication. Although not depicted, additional lumens may be added in this substantially flat configuration, laterally disposed from the primary lumen  310  and the secondary lumen  318 , as necessary to suit a particular application. 
     The above features described in connection with the multi-lumen conduits  302   a ,  302   b ,  302   c ,  302   d , and  302   e  may be used in combination with one another to suit a particular application. For example, the external absorbent layer  322  described in the multi-lumen conduit  302   d  may be used in combination with any of the multi-lumen conduits  302   a ,  302   b ,  302   c , and  302   e . Further, any of the multi-lumen conduits  302   a ,  302   b ,  302   c ,  302   d , and  302   e  may be used with padding (not shown) disposed around the external surface  306 , proximate to the dressing  124 , for example, to enhance user comfort. 
     Although this specification discloses advantages in the context of certain illustrative, non-limiting embodiments, various changes, substitutions, permutations, and alterations may be made without departing from the scope of the appended claims. Further, any feature described in connection with any one embodiment may also be applicable to any other embodiment.