WO2021084446A1

WO2021084446A1 - High-volume flexible fluid storage pouch

Info

Publication number: WO2021084446A1
Application number: PCT/IB2020/060111
Authority: WO
Inventors: Matthew Francis Ii Cavanaugh; Justin Rice; Kevin Higley; Bradley JONIETZ; Roy Dory
Original assignee: Kci Licensing, Inc.
Priority date: 2019-11-01
Filing date: 2020-10-28
Publication date: 2021-05-06

Abstract

A soft-sided or flexible storage pouch may be used with a negative-pressure therapy system to receive and store fluids and exudate from a tissue site. The flexible storage pouch may include an envelope formed from one or more polymer films. The pouch may comprise a storage compartment configured to receive and store liquid fluid or exudate from a tissue site, and a manifold compartment configured to manifold gaseous fluid from the storage compartment to a negative-pressure source. In some embodiments, the manifold compartment may at least partially surround the storage compartment. One or more filters may be disposed in various locations between the storage compartment and the manifold compartment. The filters may be configured to allow the flow of gas from the storage compartment to the manifold in any orientation of the pouch, but may reduce or prevent the flow of liquid from the storage compartment to the manifold.

Description

HIGH- VOLUME FLEXIBLE FLUID STORAGE POUCH

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/929,494, filed on November 1, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to fluid storage containers for use with tissue treatment systems.

BACKGROUND

[0003] Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negative- pressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0004] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound or a cavity can be washed out with a liquid solution for therapeutic purposes. These practices are commonly referred to as "irrigation" and "lavage" respectively. "Instillation" is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative- pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

[0005] While the clinical benefits of negative-pressure therapy and/or instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. BRIEF SUMMARY

[0006] New and useful systems, apparatuses, and methods for treating tissue in a negative- pressure therapy environment are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0007] For example, in some embodiments, a soft-sided or flexible storage pouch may be used with a negative-pressure therapy system to receive and store fluids and exudate from a tissue site. The flexible storage pouch may include an envelope formed from one or more polymer fdms. The pouch may include a storage compartment and a manifold compartment. The storage compartment may be configured to receive and store liquid fluid or exudate from a tissue site. The manifold compartment may be configured to manifold gaseous fluid from the storage compartment to a negative-pressure source. In some embodiments, the manifold compartment may at least partially surround the storage compartment. One or more filters may be disposed in various locations between the storage compartment and the manifold compartment. The one or more filters may be configured to allow the flow of gas fluid from the storage compartment to the manifold in any orientation of the pouch, but may reduce or prevent the flow of liquid fluid from the storage compartment to the manifold.

[0008] In some embodiments, the pouch may further include a filler disposed in the storage compartment. The filler may be configured to reduce or prevent collapse of the storage compartment under the application of negative-pressure. In some embodiments, the filler may be configured to manifold fluid and/or negative pressure through the storage compartment. The filler may be a felted open-cell foam in some examples. In some embodiments, the filler may include an absorbent material.

[0009] In some embodiments, the pouch may further include a filler disposed in the manifold compartment. The filler may be configured to reduce or prevent collapse of the manifold compartment under the application of negative-pressure. In some embodiments, the filler may be configured to manifold fluid and/or negative pressure through the manifold compartment. The filler may be a felted open-cell foam in some examples.

[0010] In some embodiments, a flexible fluid storage pouch may include a first layer and a second layer forming a first compartment and a second compartment. The second compartment may be at least partially surrounded by the first compartment. The pouch may further include an inlet and an outlet in the first layer. The inlet may be fluidly coupled to the second compartment, and the outlet may be fluidly coupled to the first compartment. The pouch may further include a filler disposed in the first compartment, wherein the filler may be between the second layer and the outlet.

[0011] In some embodiments, a flexible fluid storage pouch may include a first layer and a second layer. The second layer may have a peripheral portion coupled to the first layer. The pouch may include a first compartment defined by the second layer and a first portion of the first layer, and a second compartment defined by the second layer and a second portion of the first layer. The second compartment may be at least partially surrounded by the first compartment. The pouch may include an inlet in the first layer, wherein the inlet may be fluidly coupled to the second compartment, and an outlet in the first layer, wherein the outlet may be fluidly coupled to the first compartment. The pouch may include a filler disposed in the first compartment between the second layer and the outlet.

[0012] In some embodiments, a fluid storage pouch may include a flexible envelope defining an interior space and a filter layer disposed in the interior space and coupled to the flexible envelope. The pouch may include a first compartment and a second compartment. The first compartment may be defined by a first portion of the flexible envelope and the filter layer. The second compartment may be defined by a second portion of the flexible envelope and the filter layer. The second compartment may be partially surrounded by the first compartment. The pouch may include an inlet and an outlet in the flexible envelope. The inlet may be fluidly coupled to the second compartment and the outlet may be fluidly coupled to the first compartment. A filler may be disposed in the first compartment, wherein the filler may be disposed between the filter layer and the outlet.

[0013] In some embodiments, a method of manufacturing a flexible fluid storage pouch may include forming a stack. The stack may include a first layer, including a first aperture and a second aperture, a second layer, and a filler between the first layer and the second layer. The method may further include coupling the second layer to the first layer to form a first seal and a first compartment containing the filler. The second aperture may be fluidly coupled to the first compartment. The method may further include folding the stack along a fold line into a U-shaped stack, wherein the second layer is on the inside of the U-shaped stack. The method may further include coupling the stack to itself to form a second seal and a second compartment, wherein the first aperture is fluidly coupled to the second compartment.

[0014] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0016] Figure 2 is a schematic view, illustrating additional details of an example embodiment of the therapy system of Figure 1 ;

[0017] Figure 3 is an exploded isometric view of an example embodiment of a pouch that can be associated with some embodiments of the therapy system of Figure 1 ;

[0018] Figure 4 is a plan view of the pouch of Figure 3;

[0019] Figure 5 is an exploded cross-sectional view of the pouch of Figure 4 taken along line

5-5;

[0020] Figure 6 is a perspective view of the assembled pouch of Figure 3;

[0021] Figure 7 is a cross-sectional view of the pouch of Figure 6 taken along line 7-7; [0022] Figure 8 is a cross-sectional view of another example embodiment of a pouch that can be associated with some embodiments of the therapy system of Figure 1 ;

[0023] Figure 9 is a cross-sectional view of another example embodiment of a pouch that can be associated with some embodiments of the therapy system of Figure 1 ;

[0024] Figure 10 is a cross-sectional view of another example embodiment of a pouch that can be associated with some embodiments of the therapy system of Figure 1 ; and

[0025] Figure 11 is a cross-sectional view of another example embodiment of a pouch that can be associated with some embodiments of the therapy system of Figure 1.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0026] The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but it may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0027] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

[0028] Figure 1 is a simplified functional block diagram of an example embodiment of a therapy system 100 that can provide negative -pressure therapy with instillation of topical treatment solutions to a tissue site in accordance with this specification.

[0029] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

[0030] The therapy system 100 may include a source or supply of negative pressure, such as a negative-pressure source 105, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 110, and a fluid container, such as a pouch 115, are examples of distribution components that may be associated with some examples of the therapy system 100. As illustrated in the example of Figure 1, the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments.

[0031] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface may facilitate coupling a fluid conductor to the dressing 110. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0032] The therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0033] The therapy system 100 may also include a source of instillation solution. For example, a solution source 145 may be fluidly coupled to the dressing 110, as illustrated in the example embodiment of Figure 1. The solution source 145 may be fluidly coupled to a positive-pressure source, such as a positive-pressure source 150, a negative-pressure source such as the negative-pressure source 105, or both in some embodiments. A regulator, such as an instillation regulator 155, may also be fluidly coupled to the solution source 145 and the dressing 110 to ensure proper dosage of instillation solution (e.g. saline) to a tissue site. For example, the instillation regulator 155 may comprise a piston that can be pneumatically actuated by the negative-pressure source 105 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval. Additionally or alternatively, the controller 130 may be coupled to the negative-pressure source 105, the positive-pressure source 150, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 155 may also be fluidly coupled to the negative-pressure source 105 through the dressing 110, as illustrated in the example of Figure 1.

[0034] Some components of the therapy system 100 may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy. For example, in some embodiments, the negative-pressure source 105 may be combined with the controller 130, the solution source 145, and other components into a therapy unit.

[0035] In general, components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 105 may be directly coupled to the pouch 115 and may be indirectly coupled to the dressing 110 through the pouch 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. For example, the negative -pressure source 105 may be electrically coupled to the controller 130 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0036] A negative-pressure supply, such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro pump, for example. “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. References to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0037] The pouch 115 is representative of a container, canister, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site.

[0038] A controller, such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negative- pressure source 105. In some embodiments, for example, the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example. The controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

[0039] Sensors, such as the first sensor 135 and the second sensor 140, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the therapy system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 135 may be a piezo-resistive strain gauge. The second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 130. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0040] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. The tissue interface 120 may take many forms, and may have many sizes, shapes, or thicknesses, depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.

[0041] In some embodiments, the tissue interface 120 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.

[0042] In some illustrative embodiments, a manifold may comprise a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

[0043] In some embodiments, the tissue interface 120 may comprise or consist essentially of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and foam having an average pore size in a range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the tissue interface 120 may be at least 10 pounds per square inch. The tissue interface 120 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the tissue interface may be foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the tissue interface 120 may be reticulated polyurethane foam such as found in GRANUFOAM™ Dressing or V.A.C. VERAFLO™ Dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0044] The thickness of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the thickness of the tissue interface may be decreased to reduce tension on peripheral tissue. The thickness of the tissue interface 120 can also affect the conformability of the tissue interface 120. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0045] The tissue interface 120 may be either hydrophobic or hydrophilic. In an example in which the tissue interface 120 may be hydrophilic, the tissue interface 120 may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 120 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open-cell foam such as V.A.C. WHITEFOAM™ Dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0046] In some embodiments, the tissue interface 120 may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include, without limitation, polycarbonates, polyfumarates, and capralactones. The tissue interface 120 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 120 to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

[0047] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 125 may comprise or consist of, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties.

[0048] In some example embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 125 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co-polyester; and polyether block polymide copolymers. Such materials are commercially available as, for example, Tegaderm® drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane films, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m²/24 hours and a thickness of about 30 microns.

[0049] An attachment device may be used to attach the cover 125 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure -sensitive adhesive configured to bond the cover 125 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[0050] The solution source 145 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0051] In operation, the tissue interface 120 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound. The cover 125 may be placed over the tissue interface 120 and sealed to an attachment surface near a tissue site. For example, the cover 125 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment.

[0052] The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example.

[0053] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies something relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.

[0054] Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in the pouch 115.

[0055] In some embodiments, the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the therapy system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, controller 130 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 130 can operate the negative -pressure source 105 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0056] In some embodiments, the controller 130 may have a continuous pressure mode, in which the negative-pressure source 105 is operated to provide a constant target negative pressure for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode. For example, the controller 130 can operate the negative- pressure source 105 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation. The cycle can be repeated by activating the negative-pressure source 105, which can form a square wave pattern between the target pressure and atmospheric pressure.

[0057] In some example embodiments, the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous. For example, the negative-pressure source 105 and the dressing 110 may have an initial rise time. The initial rise time may vary depending on the type of dressing and therapy equipment being used. For example, some therapy systems may increase negative pressure at a rate of about 20-30 mmHg/second, and other therapy systems may increase negative pressure at a rate of about 5-10 mmHg/second. If the therapy system 100 is operating in an intermittent mode, the repeating rise time may be a value substantially equal to the initial rise time.

[0058] In some example dynamic pressure control modes, the target pressure can vary with time. For example, the target pressure may vary in the form of a triangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise rate of negative pressure set at a rate of 25 mmHg/min. and a descent rate set at 25 mmHg/min. In other embodiments of the therapy system 100, the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a rise rate of about 30 mmHg/min. and a descent rate set at about 30 mmHg/min.

[0059] In some embodiments, the controller 130 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure. The variable target pressure may also be processed and controlled by the controller 130, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform. In some embodiments, the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.

[0060] In some embodiments, the controller 130 may receive and process data, such as data related to instillation solution provided to the tissue interface 120. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes. The controller 130 may also control the operation of one or more components of the therapy system 100 to instill solution. For example, the controller 130 may manage fluid distributed from the solution source 145 to the tissue interface 120. In some embodiments, fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 105 to reduce the pressure at the tissue site, drawing solution into the tissue interface 120. In some embodiments, solution may be instilled to a tissue site by applying a positive pressure from the positive-pressure source 150 to move solution from the solution source 145 to the tissue interface 120. Additionally or alternatively, the solution source 145 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 120.

[0061] The controller 130 may also control the fluid dynamics of instillation by providing a continuous flow of solution or an intermittent flow of solution. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution. The application of negative pressure may be implemented to provide a continuous pressure mode of operation to achieve a continuous flow rate of instillation solution through the tissue interface 120, or it may be implemented to provide a dynamic pressure mode of operation to vary the flow rate of instillation solution through the tissue interface 120. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation to allow instillation solution to dwell at the tissue interface 120. In an intermittent mode, a specific fill volume and dwell time may be provided depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative-pressure treatment may be applied. The controller 130 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle.

[0062] Figure 2 is a schematic view, illustrating details of an example embodiment of the therapy system 100. The therapy system 100 is shown applied to a human patient 200, but the therapy system 100 may be used on other types of subjects. In some embodiments, the dressing 110 may be fluidly coupled to the pouch 115 with a first fluid conductor 205, and the pouch 115 may be fluidly coupled to the negative-pressure source 105 with a second fluid conductor 210. The negative-pressure source 105 may provide negative pressure through the second fluid conductor 210, the pouch 115, and the first fluid conductor 205 to the dressing 110 to remove fluids from a tissue site. Fluids may be delivered to the pouch 115 for storage and later removal. In other embodiments, the fluids may be from an ostomy bag or another source rather than dressing 110.

[0063] In some embodiments, the pouch 115 may include one or more straps 215 configured to mount the pouch 115 to a patient. Similarly, the negative -pressure source 105 may also include one or more straps 220, allowing the negative-pressure source 105 to be mounted to the patient 200. The straps 215 and the straps 220 may be elastomeric members, belt-like members, or the like. In addition, the straps 215 and the straps 220 may be adjustable, permanently secured, or releasably coupled to the pouch 115 and the negative-pressure source 105, respectively. In some embodiments, the straps 215 and the straps 220 may allow positioning of the pouch 115 and the negative-pressure source 105 at different locations on the patient 200 so that the weight of the therapy system 100 may be distributed at more than one location of the patient 200. For example, the pouch 115 may be strapped to a portion of the patient 200, such as a leg 225, using the straps 215 or other attachment devices. Similarly, the negative-pressure source 105 may be mounted to another portion of the patient 200, such as a waist 230, using the straps 220. The pouch 115 may be oriented as shown in Figure 2, or the pouch 115 may be oriented in other positions to improve fit to, and comfort of, the patient 200. In some embodiments, the negative-pressure source 105 and the pouch 115 may also be mounted at locations other than the patient 200, for example, on a bed, pole, or the like. In some embodiments, the pouch 115 may be proximate to the negative-pressure source 105. For example, in some embodiments, the negative- pressure source 105 and the pouch 115 may be placed in a fabric enclosure having a pocket for the negative-pressure source 105 and a pocket for the pouch 115. In some embodiments, the pouch 115 may be strapped to the negative-pressure source 105, or connected to the negative-pressure source 105 using one or more connectors.

[0064] Figure 3 is an exploded isometric view of an example of the pouch 115 that can be associated with some embodiments of the therapy system 100. As shown in Figure 3, the pouch 115 may comprise a first layer 300, a second layer 305, a first filler 310, and a second filler 315. The first filler 310 is configured to be sandwiched between the first layer 300 and the second layer 305. The second filler 315 may be proximate to the second layer 305 opposite the first filler 310. The first layer 300 may form an outer layer of the pouch 115 and the second layer 305 may form a filter layer within the pouch 115.

[0065] In some embodiments, the first layer 300 may be formed from or include a polymer film. In some embodiments, the first layer 300 may comprise a thermoplastic film or sheet. The first layer 300 may comprise, for example, one or more of the following materials: thermoplastic polyurethane (TPU); polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co polyester; and polyether block polymide copolymers.

[0066] In some embodiments, the first layer 300 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties. In some example embodiments, the first layer 300 may be a polymer sheet, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. If the first layer 300 has a high MVTR, some of the fluids captured by the pouch 115 may evaporate and exit the pouch 115 through the first layer 300 as water vapor. This may increase the storage capacity of the pouch 115.

[0067] As further shown in Figure 3, the first layer 300 may include a first aperture, such as an inlet 320. The inlet 320 may form a first port. A first negative-pressure interface, such as an inlet interface 325, may be placed over the inlet 320 to provide a fluid path between the first fluid conductor 205 and the second filler 315. The first layer 300 may also include a second aperture, such as an outlet 330. The outlet 330 may form a second port. A second negative-pressure interface, such as an outlet interface 335, may be placed over the outlet 330 to provide a fluid path between the second fluid conductor 210 and the first filler 310.

[0068] In some embodiments, the second layer 305 may be formed from or include a polymeric film. In some embodiments, the second layer 305 may comprise a thermoplastic film or sheet. The second layer 305 may comprise, for example, one or more of the following materials: thermoplastic polyurethane (TPU); polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co polyester; and polyether block polymide copolymers.

[0069] As shown in the example of Figure 3, in some embodiments, the second layer 305 may include one or more apertures 340. In some embodiments, the second layer 305 may have one or more comer regions 345 with an aperture 340 positioned proximate to each comer region 345. In some embodiments, the pouch 115 may comprise one or more filters 350, wherein a filter 350 may be disposed at each aperture 340. The filters 350 may be hydrophobic filters so that fluid communication into the outlet interface 335 and the second fluid conductor 210 may be limited to communication of negative-pressure, reducing or preventing liquid from flowing into the outlet interface 335 and the second fluid conductor 210. In some embodiments, the second layer 305 may have two or more filters 350. In some embodiments, the second layer 305 may have four or more filters 350. In some embodiments, the second layer 305 may have six or more filters 350.

[0070] As shown in Figure 3, the first filler 310 may generally comprise a manifold, which can provide a means for collecting or distributing fluid from the inlet 320 to the outlet 330 of the pouch 115 under pressure. For example, the first filler 310 may be adapted to receive negative pressure from a source and distribute negative pressure across the first filler 310, which may have the effect of collecting fluid from a tissue site and drawing the fluid toward the source. In some embodiments, the first filler 310 may be configured reduce or minimize pressure loss through the first filler 310. The first filler 310 may also be configured to resist collapse, compression, or contraction under the application of negative pressure. The first filler 310 may be sufficiently rigid to resist or prevent collapse, compression, or contraction under the application of negative pressure. The first filler 310 may be non- collapsible or may only allow limited collapse under negative pressure.

[0071] In some illustrative embodiments, the pathways of the first filler 310 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the first filler 310 may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that comprise or can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the first filler 310 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the first filler 310 may be molded to provide surface projections that define interconnected fluid pathways.

[0072] In some embodiments, the first filler 310 may be formed by a felting process. Any porous foam suitable for felting may be used, including the example foams mentioned herein, such as GRANUFOAM™ Dressing. In some embodiments, the first filler 310 may be reticulated polyurethane foam such as found in V.A.C. VERAFLO™ Dressing, available from Kinetic Concepts, Inc. of San Antonio, Texas. Felting comprises a thermoforming process that permanently compresses a foam to increase the density of the foam while maintaining interconnected pathways. Felting may be performed by any known methods, which may include applying heat and pressure to a porous material or foam material. Some methods may include compressing a foam blank between one or more heated platens or dies (not shown) for a specified period of time and at a specified temperature. The direction of compression may be along the thickness of the foam blank.

[0073] The period of time of compression may range from 10 minutes up to 24 hours, though the time period may be more or less depending on the specific type of porous material used. Further, in some examples, the temperature may range between 120°C to 260°C. Generally, the lower the temperature of the platen, the longer a porous material must be held in compression. After the specified time period has elapsed, the pressure and heat will form a felted structure or surface on or through the porous material or a portion of the porous material.

[0074] The felting process may alter certain properties of the original material, including pore shape and/or size, elasticity, density, and density distribution. For example, struts that define pores in the foam may be deformed during the felting process, resulting in flattened pore shapes. The deformed struts can also decrease the elasticity of the foam. The density of the foam is generally increased by felting. In some embodiments, contact with hot-press platens in the felting process can also result in a density gradient in which the density is greater at the surface and the pores size is smaller at the surface. In some embodiments, the felted structure may be comparatively smoother than any unfinished or non- felted surface or portion of the porous material. Further, the pores in the felted structure may be smaller than the pores throughout any unfinished or non-felted surface or portion of the porous material. In some examples, the felted structure may be applied to all surfaces or portions of the porous material. Further, in some examples, the felted structure may extend into or through an entire thickness of the porous material such that the all of the porous material is felted.

[0075] A felted foam may be characterized by a firmness factor, which is indicative of the compression of the foam. The firmness factor of a felted foam can be specified as the ratio of original thickness to final thickness. A compressed or felted foam may have a firmness factor greater than 1. The degree of compression may affect the physical properties of the felted foam. For example, felted foam has an increased effective density compared to a foam of the same material that is not felted. The felting process can also affect fluid-to-foam interactions. For example, as the density increases, compressibility or collapse may decrease. Therefore, foams which have different compressibility or collapse may have different firmness factors. In some example embodiments, a firmness factor can range from about 2 to about 10, preferably about 3 to about 7. For example, the firmness factor of the first filler 310 felted foam may be about 5 in some embodiments. There is a general linear relationship between firmness level, density, pore size (or pores per inch) and compressibility. The physical properties of a felted foam in relation to the physical properties of a pre-felted or unfelted foam from which the felted foam is formed may be determined by one or more of the following equations:

Average Pores per Inch_FeUed = Average Pores Per Inch_Un^_eited x Firmness Factor

(Eq. 4);

25% Compression Load Deflection_Feited =

25% Compression Load Deflection_Unf_eited x Firmness Factor (Eq. 5); and

65% Compression Load Deflection_Feited =

65% Compression Load Deflection_Unf_eited x Firmness Factor (Eq. 6).

For example, foam that is felted to a firmness factor of 3 will show a three-fold density increase and compress to about a third of its original thickness. Foam that is felted to a firmness factor of 3 may show a three-fold decrease in pore size, a three-fold decrease in free volume, a three fold increase in average pores per inch, a three-fold increase in 25% compression load deflection, and a three-fold increase in 65% compression load deflection.

[0076] In some embodiments, a suitable foam blank (e.g. of pre-felted foam) for formation of the first filler 310 may have about 40 to about 50 pores per inch on average, a density of about 1.3 to about 1.6 lb/ft³, a free volume of about 90% or more, an average pore size in a range of about 400 to about 600 microns, a 25% compression load deflection of at least 0.35 pounds per square inch, and/or a 65% compression load deflection of at least 0.43 pounds per square inch. For example, the foam blank may be GRANUFOAM™ Dressing. In some embodiments, a suitable foam blank for formation of the manifold 310 may have about 40 to about 50 pores per inch on average, a density of about 1.7 to about 2.1 lb/ft³, an average pore size in a range of about 400 to about 600 microns, a 25% compression load deflection of at least 0.35 pounds per square inch, and/or a 65% compression load deflection of at least 0.6 pounds per square inch. For example, the foam blank may be foam such as found in V.A.C. VERAFLO™ dressings. In some embodiments, the foam blank may have a thickness greater than 10 millimeters, for example 10-35 millimeters, 10-25 millimeters, 10-20 millimeters, or 15-20 millimeters. In some embodiments, the foam blank may be felted to provide denser foam for the first filler 310. For example, the foam blank may be felted to a firmness factor of 2-10. In some embodiments, the foam blank may be felted to a firmness factor of 3-7. Some embodiments may felt the foam blank to a firmness factor of 5. The first filler 310 may have a thickness in a range of about 1 millimeter to about 5 millimeters. In some embodiments, the thickness of the first filler 310 may be about 2.5 millimeters.

[0077] In some embodiments, the first filler 310 may comprise an open-cell foam having a free volume of about 13% to about 30%, a density of about 3.9 to about 11.2 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.29 to about 3.01 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 maybe about 3.9 to about 4.8 lb/ft³. In some embodiments, the free volume of the foam may be about 30%. In some embodiments, the average pore size of the first filler 310 may be about 133 to about 200 microns. In some embodiments, the first filler 310 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.29 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 may be about 6.5 to about 8.0 lb/ft³. In some embodiments, the free volume of the foam may be about 18%. In some embodiments, the average pore size of the first filler 310 may be about 80 to about 120 microns. In some embodiments, the first filler 310 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 2.15 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 may be about 9.1 to about 11.2 lb/ft³. In some embodiments, the free volume of the foam may be about 13%. In some embodiments, the average pore size of the first filler 310 may be about 57 to about 86 microns. In some embodiments, the first filler 310 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 3.01 pounds per square inch.

[0078] In some embodiments, the first filler 310 may comprise an open-cell foam having a density of about 5.1 to about 14.7 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.8 to about 4.2 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 may be about 5.1 to about 6.3 lb/fl³. In some embodiments, the average pore size of the first filler 310 may be about 133 to about 200 microns. In some embodiments, the first filler 310 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.8 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 may be about 8.5 to about 10.5 lb/ft³. In some embodiments, the average pore size ofthe first filler 310 may be about 80 to about 120 microns. In some embodiments, the first filler 310 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 3.0 pounds per square inch. In some embodiments, the density of the foam of the first filler 310 may be about 11.9 to about 14.7 lb/ft³. In some embodiments, the average pore size of the first filler 310 may be about 57 to about 86 microns. In some embodiments, the first filler 310 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the first filler 310 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 4.2 pounds per square inch.

[0079] In some embodiments, the second filler 315 may generally comprise a manifold, which can provide a means for collecting or distributing fluid from the inlet 320 to the outlet 330 of the pouch 115 under pressure. For example, the second filler 315 may be adapted to receive negative pressure from a source and distribute negative pressure across the second filler 315, which may have the effect of collecting fluid from a tissue site and drawing the fluid toward the source. In some embodiments, the second filler 315 may be configured reduce or minimize pressure loss through the second filler 315. The second filler 315 may also be configured to resist collapse, compression, or contraction under the application of negative pressure. The second filler 315 may be sufficiently rigid to resist or prevent collapse, compression, or contraction under the application of negative pressure. The second fdler 315 may be non-collapsible or may only allow limited collapse under negative pressure.

[0080] In some illustrative embodiments, the pathways of the second filler 315 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the second filler 315 may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that comprise or can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the second fdler 315 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the second fdler 315 may be molded to provide surface projections that define interconnected fluid pathways.

[0081] In some embodiments, the second fdler 315 may be formed by a felting process. Any porous foam suitable for felting may be used, including GRANUFOAM™ Dressing or reticulated polyurethane foam such as found in V.A.C. VERAFLO™ Dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas. In some example embodiments, the second fdler 315 may have a firmness factor can range from about 2 to about 10, preferably about 3 to about 7. For example, the firmness factor of the second fdler 315 felted foam may be about 5 in some embodiments. In some embodiments, the firmness factor of the second fdler 315 felted foam may be about 7.

[0082] In some embodiments, a suitable foam blank (e.g. of pre-felted foam) for formation of the second fdler 315 may have about 40 to about 50 pores per inch on average, a density of about 1.3 to about 1.6 lb/ft³, a free volume of about 90% or more, an average pore size in a range of about 400 to about 600 microns, a 25% compression load deflection of at least 0.35 pounds per square inch, and/or a 65% compression load deflection of at least 0.43 pounds per square inch. In some embodiments, the foam blank may have a thickness greater than 10 millimeters, for example 10-35 millimeters, 10-25 millimeters, 10-20 millimeters, or 15-20 millimeters. In some embodiments, the foam blank may be felted to provide denser foam for the second fdler 315. For example, the foam blank may be felted to a firmness factor of 2-10. In some embodiments, the foam blank may be felted to a firmness factor of 3-7. Some embodiments may felt the foam blank to a firmness factor of 5. The second fdler 315 may have a thickness in a range of about 5 millimeter to about 100 millimeters. In some embodiments, the second fdler 315 may have a thickness in a range of about 10 millimeter to about 50 millimeters. In some embodiments, the second fdler 315 may have a thickness of about 16 millimeters.

[0083] In some embodiments, the second fdler 315 may comprise an open-cell foam having a free volume of about 13% to about 30%, a density of about 3.9 to about 11.2 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the second fdler 315 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.29 to about 3.01 pounds per square inch. In some embodiments, the density of the foam of the second filler 315 may be about 3.9 to about 4.8 lb/ft³. In some embodiments, the free volume of the foam may be about 30%. In some embodiments, the average pore size of the second filler 315 may be about 133 to about 200 microns. In some embodiments, the second filler 315 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the second filler 315 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.29 pounds per square inch. In some embodiments, the density of the foam of the second filler 315 may be about 6.5 to about 8.0 lb/ft³. In some embodiments, the free volume of the foam may be about 18%. In some embodiments, the average pore size of the second filler 315 may be about 80 to about 120 microns. In some embodiments, the second filler 315 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the second filler 315 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 2.15 pounds per square inch. In some embodiments, the density of the foam of the second filler 315 may be about 9.1 to about 11.2 lb/ft³. In some embodiments, the free volume of the foam may be about 13%. In some embodiments, the average pore size of the second filler 315 may be about 57 to about 86 microns. In some embodiments, the second filler 315 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the second filler 315 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 3.01 pounds per square inch.

[0084] In some embodiments, the second filler 315 may comprise an open-cell foam having a density of about 5.1 to about 14.7 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the second filler 315 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.8 to about 4.2 pounds per square inch. In some embodiments, the density of the foam of the second filler 315 may be about 5.1 to about 6.3 lb/ft³. In some embodiments, the average pore size of the second filler 315 may be about 133 to about 200 microns. In some embodiments, the second filler 315 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the second filler 315 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.8 pounds per square inch. In some embodiments, the density of the foam of the second filler 315 may be about 8.5 to about 10.5 lb/ft³. In some embodiments, the average pore size ofthe second filler 315 may be about 80 to about 120 microns. In some embodiments, the second filler 315 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the second fdler 315 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 3.0 pounds per square inch. In some embodiments, the density of the foam of the second fdler 315 may be about 11.9 to about 14.7 lb/ft³. In some embodiments, the average pore size of the second fdler 315 may be about 57 to about 86 microns. In some embodiments, the second fdler 315 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the second fdler 315 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 4.2 pounds per square inch.

[0085] In some embodiments, the second fdler 315 may comprise a closed-cell foam. For example, the second fdler 315 may comprise or consist essentially of silicone, polyurethane (PU), or ethylene vinyl acetate (EVA). For example, the second fdler 315 may be a closed-cell foam having an average pore size in a range of about 0.2 millimeters (200 microns) to about 1 millimeter (1000 microns). In some embodiments, the second fdler 315 may be a closed-cell foam having a porosity in a range of about 200 pores per inch to about 30 pores per inch.

[0086] As further shown in Figure 3, in some embodiments, the second fdler 315 may have one or more passages, which can be distributed uniformly or randomly across the second fdler 315. As illustrated in the example of Figure 3, the passages may comprise or consist essentially of perforations 355 in the second fdler 315. The perforations 355 may be formed by removing material from the second fdler 315. For example, the perforations 355 may be formed by cutting through the second fdler 315. In some embodiments, the passages may comprise fenestrations, slits, slots, apertures, or holes.

[0087] Figure 4 is a plan view of a portion of an example of the pouch 115 that can be associated with some embodiments of the therapy system 100. As shown in Figure 4, in some embodiments, the first layer 300 may have a first length 400 and a first width 401 and the second layer 305 may have a second length 402 and a second width 403, wherein the second length 402 and the second width 403 may be less than the first length 400 and the first width 401, respectively. In some embodiments, the first layer 300 may have a first surface area A; and the second layer 305 may have a second surface area A , wherein the first surface area A may be greater than the second surface area 4 .

[0088] As further shown in Figure 4, The first layer 300, second layer 305, and first fdler 310 may be assembled into a stack 404 which can be folded around the second fdler 315 to form the pouch 115. The stack 404 may be configured to be folded into a U-shape along a fold line 405. On opposite sides of the fold line 405 may be a first side 406 and a second side 410. The first layer 300 may have a first portion 415 on the first side 406 of the fold line 405 and a second portion 420 on the second side 410 of the fold line 405. The second layer 305 may have a first portion 425 on the first side 406 of the fold line 405 and a second portion 430 on the second side 410 of the fold line 405.

[0089] A peripheral portion of the second layer 305 may be coupled to the first layer 300. The first layer 300 and the second layer 305 may be adhered together in some embodiments. Suitable bonds between the first layer 300 and the second layer 305 may include pressure-sensitive adhesive (reactive and non-reactive types); hot melt adhesive (spray applied or deployed as a film, woven, or non-woven); hot press lamination; or flame lamination. In some embodiments, the first layer 300 and the second layer 305 may be welded together. For example, the peripheral portion of the first layer 300 may be welded together using heat, radio frequency (RF) welding, or other methods to generate heat such as ultrasonic welding. RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene. In some embodiments, a weld 435 may extend around the peripheral portion of the second layer 305 where it is coupled to the first layer 300. The weld 435 may form a first seal.

[0090] In some embodiments, the inlet 320 may be located in the first portion 415 of the first layer 300 on the first side 406 of the fold line 405. The inlet 320 may be outside the weld 435. The outlet 330 may be located in the second portion 420 of the first layer 300 on the second side 410 of the fold line 405. The outlet 330 may be inside the weld 435.

[0091] In some embodiments, a first filter 350 of the one or more filters 350 may be located in the first portion 415 of the second layer 305 and a second filter 350 of the one or more filters 350 may be located in the second portion 420 of the second layer 305. In some embodiments, at least one filter 350 may be located on the second layer 305 on the first side 406 of the fold line 405 and at least one filter 350 may be located on the second layer 305 on the second side 410 of the fold line 405. As illustrated in Figure 4, in some embodiments, the filters 350 may be disposed over the first filler 310. In some embodiments, the filters 350 may be disposed proximate to a peripheral portion 440 of the first filler 310.

[0092] Figure 5 is an exploded cross-sectional view of the pouch of Figure 4 taken along line 5-5. As shown in Figure 5, the weld 435, the second layer 305, and a portion of the first layer 300 cooperate to form a first compartment 500. The first filler 310 may be disposed in the first compartment 500 between the first layer 300 and the second layer 305. The outlet 330 may be fluidly coupled with the first compartment 500. The apertures 340 may be fluidly coupled with the first compartment 500.

[0093] As further shown in Figure 5, in some embodiments, during manufacture of the pouch 115, the stack 404 may be folded upward (as shown by arrows 505) along the fold line 405 into a U- shape or taco-shape to bring a peripheral portion of the first portion 415 of the first layer 300 proximate to a peripheral portion of the second portion 420 of the first layer 300. The second layer 305 may be on the inside of the U-shaped stack 404. The U-shaped stack 404 may be folded around at least three sides of the second filler 315.

[0094] Figure 6 is a perspective view of the assembled pouch 115 of Figure 3. As shown in Figure 6, the peripheral portions of the first portion 415 and the second portion 420 of the first layer 300 may be coupled together. The first layer 300 may be adhered to itself in some embodiments. Suitable bonds between the peripheral portions of the first layer 300 may include pressure-sensitive adhesive (reactive and non-reactive types); hot melt adhesive (spray applied or deployed as a film, woven, or non-woven); hot press lamination; or flame lamination. In some embodiments, the peripheral portions of the first layer 300 may be welded together. For example, the first layer 300 may be and the second layer 305 may be welded together using heat, radio frequency (RF) welding, or other methods to generate heat such as ultrasonic welding. RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene. A weld 600 may extend around the peripheral portion of the first layer 300, forming a second seal.

[0095] Figure 7 is a cross-sectional view of the pouch of Figure 6 taken along line 7-7. As shown in Figure 7, the pouch 115 may have a first side 700 and a second side 705 opposite the first side 700. The pouch 115 may comprise a flexible envelope 710 having an interior space 715. As shown in the example of Figure 7, the peripheral portions of the first layer 300 may be coupled together to form the envelope 710. The weld 600, a portion of the first layer 300, and the second layer 305 may cooperate to form a second compartment 720. In some embodiments, the first compartment 500 may have a U- shape with the second compartment 720 at least partially disposed between the first compartment 500. The second compartment 720 may be at least partially surrounded by the first compartment 500. The second filler 315 may be disposed in the second compartment 720. In some embodiments, the second layer 305 may be considered to divide the interior space 715 of the envelope 710 into the first compartment 500 and the second compartment 720. The second compartment 720 may be configured to receive and store fluid from a tissue site. The size of the second compartment 720 may define the storage volume of the pouch 115. In some embodiments, the pouch 115 may have a high ratio of open volume to solid volume within the second compartment 720. The second filler 315 may provide a high open volume while also providing structure which may resist collapse under the application of negative pressure.

[0096] As shown in Figure 7, the inlet 320 may be proximate to the first side 700 of the pouch 115 and the outlet 330 may be proximate to the second side 705 of the pouch 115. The inlet 320 may be fluidly coupled with the second compartment 720 and the outlet 330 may be fluidly coupled with the first compartment 500. One or more filters 350 may be proximate the first side 700 of the pouch 115 and one or more filters 350 may be proximate the second side 705 of the pouch 115. At least a portion of the second compartment 720 may be between the one or more filters 350 proximate the first side 700 and the one or more filters 350 proximate the second side 705.

[0097] In use, the pouch 115 may be fluidly coupled to the dressing 110 at a tissue site and the negative-pressure source 105. Negative pressure may be applied to the dressing 110 by the negative- pressure source 105 through the pouch 115. Fluid may flow through the pouch 115 along flow path 725. Fluid may be removed from the tissue site and may flow through the first fluid conductor 205, the inlet interface 325, and the inlet 320 of the pouch 115 and into the second compartment 720. Liquid fluid from the tissue site may be deposited and stored in the second compartment 720, which may be considered a fluid storage compartment. The second filler 315 in the second compartment 720 may prevent collapse of the second compartment 720 under negative pressure and may aid in maximizing the volume of liquid fluid that can be stored in the second compartment 720. For example, the second fdler 315 may hold open the second compartment 720 so that at least 80% to 90% of the volume of the second compartment 720 can be filled with liquid fluid. The second compartment 720 may be able to store a high volume of fluid.

[0098] As negative pressure is applied to the dressing 110, fluid is drawn toward and through the one or more filters 350 of the second layer 305. The one or more filters 350 reduce or prevent liquid fluid from flowing into the first compartment 500 from the second compartment 720, and subsequently into the outlet interface 335 and the second fluid conductor 210. The one or more filters 350 may ensure that gaseous or substantially gaseous fluid is drawn into the first compartment 500 and the negative- pressure source 105. In some embodiments, negative pressure may only flow through the filters 350 when the filters 350 are not blocked by liquid. Disposing one or more filters 350 proximate the first side 700 of the pouch 115 and one or more filters 350 proximate the second side 705 of the pouch 115 may allow negative pressure and fluid to flow through the pouch 115 as the pouch 115 fills with liquid fluid and/or if the pouch 115 is used any orientation. As the second compartment 720 fills with exudate, gravity will pull the exudate to the lowest point in the second compartment 720. The filters 450 may be placed to allow at least one filter 450 to be at a high point within the second compartment 720, allowing air to continue to be pulled through the one or more filters 450 and through the first filler 310. For example, if one or more of the filters 350 on the first side 700 of the pouch 115 becomes blocked by liquid stored in the second compartment 720 prior to the pouch 115 being filled, one or more of the filters 350 on the second side 705 of the pouch 115 may still not be blocked by liquid and may allow the flow of negative pressure through the pouch 115. As shown in the orientation of Figure 7, one or more of the filters 350 on the first side 700 of the pouch 115 may be offset horizontally from one or more of the filters 350 on the second side 705 of the pouch 115. In some embodiments, the filters 350 on opposite sides of the pouch 115 may not be coaxially located. Placing the one or more filters 350 in different positions may allow the pouch 115 to be positioned in any orientation without inhibiting the ability of the pouch 115 to substantially fill. The one or more filters 350 may be positioned in the pouch 115 such that in any orientation of the pouch 115 during use, the one or more filters 350 may allow continued supply of reduced pressure to the second compartment 720 until the second compartment 720 may be substantially filled by exudate.

[0099] Additionally, the first filler 310 may serve to fluidly couple each of the filters 350 and may provide a contiguous path from the dressing 110 to the negative-pressure source 105. As the first filler 310 may manifold fluid from the filters 350 to the outlet 330, the first compartment 500 may be considered a manifold compartment. The negative-pressure source 105 may continue to pull or transport fluid through the therapy system 100 until the therapy system 100 achieves equilibrium (awaiting exudate to be produced by the tissue site before fluid flow resumes) and/or the second compartment 720 fills to the point that all filters 350 are become occluded by exudate and the flow of fluid through the filters 350 stops.

[00100] Figure 8 is a cross-sectional view of another example embodiment of the pouch 115 that can be associated with some embodiments of the therapy system 100. As shown in Figure 8, in some embodiments, the second layer 305 may comprise a filter material configured to prevent the flow of liquid fluids from the second filler 315 to the first filler 310. For example, some or all of the surface area A 2 of the second layer 305 may be a filter material, such as a hydrophobic filter. In some embodiments, the second layer 305 may comprise a single filter 450 having a filter surface area in a range of about 75% to about 100% of the surface area A 2 of the second layer 305. The pressure drop across the second layer 305 may be reduced as the filter surface area is increased. As shown in Figure 8, the second layer 305 may have a U-shape. Embodiments of the pouch 115 in which the second layer 305 comprises a filter material may be able to be used in any orientation. Increasing the surface area of the filter, either by increasing the surface area of the one or more filters 350 or by forming the second layer 305 from a filter material, may increase the possibility that a portion of the filter is not occluded or blocked by liquid in the second compartment 720. This may aid in maximizing the amount of liquid fluid that can be held in the pouch 115 before the pressure drops outside of a desired range and the pouch 115 needs removal and/or replacement.

[00101] As shown in Figure 8, in some embodiments, the second filler 315 may comprise a fluid distributor, such as a serpentine manifold 800, and one or more fluid storage layers, such as one or more absorbent layers 805, between the manifold 800.

[00102] The manifold 800 generally comprises one or more manifolds or manifold layers, which can provide a means for collecting or distributing fluid from the inlet 320 to the outlet 330 of the pouch 115 under pressure. For example, the manifold 800 may be adapted to receive negative pressure from a source and distribute negative pressure along the length of the manifold 800, which may have the effect of collecting fluid from a tissue site and drawing the fluid toward the source. In some embodiments, the manifold 800 may comprise one or more layers 810 and one or more connectors 815, wherein the layers 810 and the connectors 815 are fluidly coupled. In some embodiments, the layers 810 of the manifold 800 may be parallel to one another. In some embodiments, the connectors 815 may be curved.

[00103] In some illustrative embodiments, the pathways of the manifold 800 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the manifold 800 may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that comprise or can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. In some embodiments, the manifold 800 may be hydrophilic. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the manifold 800 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the manifold 800 may be molded to provide surface projections that define interconnected fluid pathways.

[00104] In some embodiments, the manifold 800 may be formed by a felting process. Any porous foam suitable for felting may be used, including GRANUFOAM™ Dressing or reticulated polyurethane foam such as found in V.A.C. VERAFLO™ Dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas. In some example embodiments, the manifold 800 may have a firmness factor can range from about 2 to about 10, preferably about 3 to about 7. For example, the firmness factor of the manifold 800 felted foam may be about 5 in some embodiments.

[00105] In some embodiments, a suitable foam blank (e.g. of pre-felted foam) for formation of the manifold 800 may have about 40 to about 50 pores per inch on average, a density of about 1.3 to about 1.6 lb/ft³, a free volume of about 90% or more, an average pore size in a range of about 400 to about 600 microns, a 25% compression load deflection of at least 0.35 pounds per square inch, and/or a 65% compression load deflection of at least 0.43 pounds per square inch. For example, the foam blank may be GRANUFOAM™ Dressing. In some embodiments, a suitable foam blank for formation of the manifold 800 may have about 40 to about 50 pores per inch on average, a density of about 1.7 to about 2.1 lb/ft³, an average pore size in a range of about 400 to about 600 microns, a 25% compression load deflection of at least 0.35 pounds per square inch, and/or a 65% compression load deflection of at least 0.6 pounds per square inch. For example, the foam blank may be foam such as found in V.A.C. VERAFLO™ Dressings. In some embodiments, the foam blank may have a thickness greater than 10 millimeters, for example 10-35 millimeters, 10-25 millimeters, 10-20 millimeters, or 15-20 millimeters. In some embodiments, the foam blank may be felted to provide denser foam for the manifold 800. For example, the foam blank may be felted to a firmness factor of 2-10. In some embodiments, the foam blank may be felted to a firmness factor of 3-7. Some embodiments may felt the foam blank to a firmness factor of 5. The layers 810 and the connectors 815 of the manifold 800 may each have a thickness in a range of about 1 millimeter to about 5 millimeters. In some embodiments, the thickness of each of the layers 810 and the connectors 815 may be about 2.5 millimeters.

[00106] In some embodiments, the manifold 800 may comprise an open-cell foam having a free volume in a range of about 13%to about 30%, a density of about 3.9 to about 11.2 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.29 to about 3.01 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 3.9 to about 4.8 lb/ft³. In some embodiments, the free volume of the foam may be about 30%. In some embodiments, the average pore size of the manifold 800 may be about 133 to about 200 microns. In some embodiments, the manifold 800 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.29 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 6.5 to about 8.0 lb/ft³. In some embodiments, the free volume of the foam may be about 18%. In some embodiments, the average pore size of the manifold 800 may be about 80 to about 120 microns. In some embodiments, the manifold 800 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the second fdler 315 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 2.15 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 9.1 to about 11.2 lb/ft³. In some embodiments, the free volume of the foam may be about 13%. In some embodiments, the average pore size of the manifold 800 may be about 57 to about 86 microns. In some embodiments, the manifold 800 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 3.01 pounds per square inch.

[00107] In some embodiments, the manifold 800 may comprise an open-cell foam having a density of about 5.1 to about 14.7 lb/ft³, about 120 to about 350 pores per inch on average (e.g., as measured in the direction of compression), and/or average pore size of about 57 to about 200 microns (e.g., as measured in the direction of compression), which may be particularly advantageous under negative pressure. For example, the denser foam may better maintain fluid flow when under negative pressure. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of about 1.05 to about 2.45 pounds per square inch and a 65% compression load deflection of about 1.8 to about 4.2 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 5.1 to about 6.3 lb/ft³. In some embodiments, the average pore size of the manifold 800 may be about 133 to about 200 microns. In some embodiments, the manifold 800 may have about 120 to about 150 pores per inch on average. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of at least 1.05 pounds per square inch and a 65% compression load deflection of at least 1.8 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 8.5 to about 10.5 lb/ft³. In some embodiments, the average pore size of the manifold 800 may be about 80 to about 120 microns. In some embodiments, the manifold 800 may have about 200 to about 250 pores per inch on average. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of at least 1.75 pounds per square inch and a 65% compression load deflection of at least 3.0 pounds per square inch. In some embodiments, the density of the foam of the manifold 800 may be about 11.9 to about 14.7 lb/ft³. In some embodiments, the average pore size of the manifold 800 may be about 57 to about 86 microns. In some embodiments, the manifold 800 may have about 280 to about 350 pores per inch on average. In some embodiments, the foam of the manifold 800 may have a 25% compression load deflection of at least 2.45 pounds per square inch and a 65% compression load deflection of at least 4.2 pounds per square inch.

[00108] In some embodiments, the foam forming the manifold 800 may be cut perpendicular to the felting direction to provide pore structures that run parallel to the fluid path created by the manifold 800. Felting may compress the pores in the direction of felting. For example, the pores in the foam forming the manifold 800 may have a first average cross-sectional area perpendicular to the direction of felting and a second average cross-sectional area parallel to the direction of felting, wherein the first average cross-sectional area is less than the second average cross-sectional area. The pores in the foam may be smaller perpendicular to the direction of felting, than parallel to the direction of felting. In some embodiments, the foam forming the manifold 800 may be oriented so that the first average cross-sectional area is perpendicular to the length of the manifold 800 and the second cross-sectional area is parallel to the length of the manifold 800. The larger second average cross-sectional area of the pores may face an absorbent layer 805. The air in the fluid flowing through the manifold 800 may flow through the smaller first average cross-sectional area without a significant pressure drop, while the liquid in the fluid flowing through the manifold 800 may fall through the larger second average cross- sectional area and into the absorbent layers 805. Orienting the length of the manifold 800 perpendicular to the felting direction may assist with reducing pressure drop across the manifold 800, may increase the manifolding of fluid through the manifold 800, and may increase the amount of liquid fluid absorbed by the absorbent layers 805.

[00109] While the various physical properties of the manifold 800 are described as achieved via a felting process, in some embodiments, the physical properties of the manifold 800 may be achieved by other methods.

[00110] The absorbent layers 805 may be disposed between the layers 810 of the manifold 800. The absorbent layers 805 store, or immobilize, the liquid from a tissue site. The absorbent layers 805 may be any substance capable of storing a liquid, such as exudate. For example, the absorbent layers 805 may form a chemical bond with exudate from the tissue site. Non-limiting examples of the absorbent layers 805 include super absorbent fiber/particulates, hydrofibre, sodium carboxymethyl cellulose, and/or alginates. In some exemplary embodiments, the absorbent layers 805 may be formed of a superabsorbent polymer (SAP). Generally, relative to their mass, SAPs can absorb and retain large quantities of liquid, and in particular water. SAPs may be used to hold and stabilize or solidify wound fluids. The SAPs used to form the absorbent layers 805 may be of the type often referred to as “hydrogels,” “super-absorbents,” or “hydrocolloids.” When disposed within the pouch 115, the SAPs may be formed into fibers or spheres to manifold reduced pressure until the SAPs become saturated. Spaces or voids between the fibers or spheres may allow a reduced pressure that is applied to the pouch 115 to be transferred within and through the absorbent layers 805. In some embodiments, fibers of the absorbent layers 805 may be either woven or non-woven. In some embodiments, the absorbent layers 805 may comprise a substrate in which the SAPs may be dispersed as pellets throughout and/or embedded as a sheet-like layer within the substrate.

[00111] The SAPs may be formed in several ways, for example, by gel polymerization, solution polymerization, or suspension polymerization. Gel polymerization may involve blending of acrylic acid, water, cross-linking agents, and ultraviolet (UV) initiator chemicals. The blended mixture may be placed into a reactor where the mixture is exposed to UV light to cause crosslinking reactions that form the SAP. The mixture may be dried and shredded before subsequent packaging and/or distribution. Solution polymerization may involve a water based monomer solution that produces a mass of reactant polymerized gel. The monomer solution may undergo an exothermic reaction that drives the crosslinking of the monomers. Following the crosslinking process, the reactant polymer gel may be chopped, dried, and ground to its final granule size. Suspension polymerization may involve a water- based reactant suspended in a hydrocarbon-based solvent. However, the suspension polymerization process must be tightly controlled and is not often used.

[00112] SAPs absorb liquids by bonding with water molecules through hydrogen bonding. Hydrogen bonding involves the interaction of a polar hydrogen atom with an electronegative atom. As a result, SAPs absorb water based on the ability of the hydrogen atoms in each water molecule to bond with the hydrophilic polymers of the SAP having electronegative ionic components. High absorbing SAPs are formed from ionic crosslinked hydrophilic polymers such as acrylics and acrylamides in the form of salts or free acids. Because the SAPs are ionic, they are affected by the soluble ionic components within the solution being absorbed and will, for example, absorb less saline than pure water. The lower absorption rate of saline is caused by the sodium and chloride ions blocking some of the water absorbing sites on the SAPs. If the fluid being absorbed by the SAP is a solution containing dissolved mineral ions, fewer hydrogen atoms of the water molecules in the solution may be free to bond with the SAP. Thus, the ability of an SAP to absorb and retain a fluid may be dependent upon the ionic concentration of the fluid being absorbed. For example, an SAP may absorb and retain de-ionized water up to 500 times the weight of the dry SAP. In volumetric terms, an SAP may absorb fluid volumes as high as 30 to 60 times the dry volume of the SAP. Other fluids having a higher ionic concentration may be absorbed at lower quantities. For example, an SAP may only absorb and retain a solution that is 0.9% salt (NaCl) up to 50 times the weight of the dry SAP. Since wound fluids contain salts, such as sodium, potassium, and calcium, the absorption capacity of the SAP may be reduced if compared to the absorption capacity of deionized water.

[00113] In some embodiments, the absorbent layers 805 may comprise a KERRAMAX CARE™ Super-Absorbent Dressing material available from Kinetic Concepts, Inc. of San Antonio, Texas. For example, the absorbent layers 805 may comprise a superabsorbent laminate comprised of 304 g.s.m. FAVOR-PAC™ 230 superabsorbent powder glued by PAFRA™ 8667 adhesive between two layers of 50 g.s.m. LIDRO™ non-woven material. In some embodiments, the absorbent layers 805 may comprise an absorbent available from Gelok International. In addition, the pouch 115 may include any number of absorbent layers 805. For example, the amount of absorbent layers 805 may be varied to increase or decrease the liquid storage capacity of the pouch 115. The presence of the absorbent layers 805 may also help to minimize fluid loss or reflux.

[00114] As further shown in Figure 8, in some embodiments, the pouch 115 may comprise one or more wicking layers 820. In some embodiments, a wicking layer 820 may be disposed between an absorbent layer 805 and a layer 810 of the manifold 800. In some embodiments, two wicking layers 820 may be disposed on either side of an absorbent layer 805. The absorbent layers 805 and the wicking layers 820 may be in a stacked relationship between layers 810 of the manifold 800. In some embodiments, the wicking layers 820 may be coupled to the absorbent layers 805. The wicking layers 820 may aid in removal of liquid fluid from the manifold 800, where the liquid fluid may be absorbed by the absorbent layers 805. The wicking layers 820 may comprise a wicking material having flow channels that support the flow of fluids through the width of the wicking layer 820. In some embodiments, the wicking layers 820 may comprise a non-woven material.

[00115] Figure 9 is a cross-sectional view of another example embodiment of the pouch 115 that can be associated with some embodiments of the therapy system 100. As shown in Figure 9, in some embodiments, the second filler 315 may comprise the manifold 800 at least partially surrounding a core 900. As shown in the example, the manifold 800 may comprise two layers 810 and a single connector 815 fluidly coupled to the layers 810. The core 900 may be disposed between the two layers 810 of the manifold 800. In some embodiments, the manifold 800 may form a pouch that encapsulates the core 900, wherein the manifold 800 may be a reticulated hydrophilic open-cell foam. In some embodiments, the core 900 may be formed from a non-collapsing or non-compressible material. For example, in some embodiments, the core 900 may be a closed-cell foam having a plurality of apertures. In some embodiments, the core 900 may also comprise an absorbent, such as a super absorbent polymer (SAP). The core 900 may be sufficiently rigid to reduce or prevent the second compartment 720 from collapsing under the application of negative pressure.

[00116] As further shown in Figure 9, in some embodiments, the pouch 115 may further comprise a filter 905 fluidly coupled with and disposed between the outlet 330 and the outlet interface 335. In some embodiments, the filter 905 may comprise an activated charcoal filter configured to reduce odors exiting the pouch 115. In some embodiments, the pouch 115 may comprise a check valve 910 or one-way valve fluidly coupled with and disposed between the inlet 320 and the inlet interface 325. The check valve may be configured to prevent liquid fluid stored in the second compartment 720 from entering the inlet interface 325 and returning to the tissue site.

[00117] Figure 10 is a cross-sectional view of another example embodiment of the pouch 115 that can be associated with some embodiments of the therapy system 100. In some embodiments, the second filler 315 may comprise more than one layer of foam. For example, as shown in Figure 10, in some embodiments, the second filler 315 may comprise a layer of perforated foam sandwiched between two layers of non-perfbrated foam. In some embodiments, the second filler 315 may comprise two manifold layers. In some embodiments, the second fdler 315 may comprise more than three manifold layers.

[00118] Figure 11 is a cross-sectional view of another example embodiment of the pouch 115 that can be associated with some embodiments of the therapy system 100. In some embodiments, the second fdler 315 may comprise one or more spheres or balls 1100. In some embodiments, the balls 1100 may comprise open-cell foam. In some embodiments, the balls 1100 may comprise closed-cell foam. In some embodiments, the balls 1100 may be made of a rigid shell material and may have a hollow center with one or more holes extending through the shell. In some embodiments, the second fdler 315 may comprise balls 1100 having a structure like that of a WIFFLE™ball.

[00119] In some embodiments, the second fdler 315 may comprise one or more different fdler materials. For example, in some embodiments, the second fdler 315 may comprise a layer of closed cell perforated foam sandwiched between two layers of open-cell felted foam. In some embodiments, the second fdler 315 may comprise perforated soft polyurethane (PU) struts. In some embodiments, the second fdler 315 may be a polymer lattice structure. For example, the second fdler 315 may be formed from thermoplastic elastomers (TPE), such as styrene ethylene butylene styrene (SEBS) copolymers, or thermoplastic polyurethane (TPU). The second fdler 315 may be formed by combining sheets of TPE or TPU having a thickness between about 0.2 mm and about 2.0 mm to form a multi -ply structure. In some embodiments, the sheets of TPE or TPU may be bonded, welded, adhered, or otherwise coupled to one another. For example, in some embodiments, the sheets of TPE or TPU may be welded using radiant heat, radio-frequency welding, or laser welding. Supracor, Inc., Hexacor, Ltd., Hexcel Corp., and Econocorp, Inc. may produce suitable TPE or TPU sheets for the formation of the second fdler 315.

[00120] Other suitable materials for the second fdler 315 may include non-woven fabrics; three-dimensional (3D) polymeric structures, such as molded polymers, embossed and formed films, and fusion-bonded films, and mesh, for example. In some examples, the second fdler 315 may include one or more layers of a 3D textile. A 3D textile of polyester fibers may be particularly advantageous for some embodiments. For example, the second fdler 315 may comprise or consist essentially of a three-dimensional weave of polyester fibers. In some embodiments, the fibers may be elastic in at least two dimensions. A fabric of polyester and cotton fibers having a weight of about 650 grams per square meter and a thickness of about 1-2 millimeters may be particularly advantageous for some embodiments. Such a fabric may have a warp tensile strength of about 330-340 kilograms and a weft tensile strength of about 270-280 kilograms in some embodiments. Another particularly suitable material may be a polyester spacer fabric having a weight of about 470 grams per square meter, which may have a thickness of about 4-5 millimeters in some embodiments. Such a spacer fabric may have a compression strength of about 20-25 kilopascals (at 40% compression). Additionally or alternatively, the second fdler 315 may comprise or consist of a material having substantial linear stretch properties, such as a polyester spacer fabric having 2-way stretch and a weight of about 380 grams per square meter. A suitable spacer fabric may have a thickness of about 3-4 millimeters, and may have a warp and weft tensile strength of about 30-40 kilograms in some embodiments. The fabric may have a close- woven layer of polyester on one or more opposing faces in some examples. Suitable 3D textiles may be produced by Heathcoat Fabrics, Ltd., Baltex, and Mueller Textil Group.

[00121] In some embodiments, the flexible fluid storage pouch 115 may be manufactured according to a method comprising the following steps. The first layer 300, the second layer 305, and the first filler 310 may be provided to form the stack 404. The first layer 300 may include the inlet 320 and the outlet 330. The first filler 310 may be disposed between the first layer 300 and the second layer 305. The second layer 305 may be coupled to the first layer 300 to form a first seal and the first compartment 500 containing the first filler 310, wherein the outlet 330 may be fluidly coupled to the first compartment 510. The stack 404 may be folded along a fold line 405 into a U-shaped stack 404, wherein the second layer 305 is on the inside of the U-shaped stack 404. The stack 404 may be coupled to itself to form a second seal and the second compartment 720, wherein the inlet 320 is fluidly coupled to the second compartment 720. In some embodiments, prior to coupling the stack 404 to itself the second filler 315 may be provided, wherein after the second seal is formed, the second filler 315 may be disposed in the second compartment 720.

[00122] The systems, apparatuses, and methods described herein may provide significant advantages. For example, in some embodiments, the pouch 115 may be flexible, allowing the pouch 115 to conform to a portion of the body of the patient 200, thereby enhancing safety and comfort of the patient 200. In addition, the flexible nature of the pouch 115 may allow the pouch 115 to be stored in a small space. The pouch 115 may be relatively easy to manufacture and may be brought to market quicker due, as only simple tooling may be required to manufacture. The pouch 115 may also be easier to ship due to light weight and small size. Additionally, the pouch 115 does not require complicated device interface points, gaskets, or seals to be coupled with the negative-pressure source 105. The pouch 115 may also have a low profile which may allow a large number of pouches 115 to fit on a pallet, allowing a large number of pouches 115 to be sterilized at a time, and thereby reducing costs. Moreover, if the pouch 115 is used with animals, the flexible nature may help prevent injury, for example, if the animal bumps surfaces or rolls over.

[00123] As disclosed herein, the therapy system 100 can provide a flexible canister or pouch 115 that manifolds fluid and air to provide a low pressure drop and an increased storage capacity of exudates and other fluids from the tissue site within the pouch 115. The inclusion of the second layer 305 comprising a filter material or one or more filters 350 may allow the pouch 115 to be used in multiple orientations without pooling of exudate within the pouch 115 or premature blockage of the second layer 305 and/or filter 350, allowing the pouch 115 to fill to its maximum capacity. The pouch 115 may be able to store a higher volume capacity of liquid fluid without false full alarms. Multiple orientation use of the pouch 115 may permit use of the pouch 115 in a wider variety of locations, and persons. In addition, multiple orientation use of the pouch 115 may permit the pouch 115 to be used in a mobile environment. The pouch 115 may further hold large volumes of liquid fluid without an increased footprint when not under negative pressure.

[00124] Additionally, forming one or more of the first layer 300 and the second layer 305 of the pouch 115 from a material having a MVTR may extend the useful life of the pouch 115. Once the pouch 115 is full, it will no longer allow negative pressure to be delivered to the tissue site. However, allowing evaporation of liquids through the envelope 710 of the pouch 115 may allow for more fluid to be removed from the tissue site and stored in the second compartment 720 before filling the second compartment 720, effectively increasing the storage capacity of the pouch 115.

[00125] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles “a” or “an” do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing 110, the container 115, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components.

[00126] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.

Claims

CLAIMS What is claimed is:

1. A flexible fluid storage pouch comprising: a first layer; a second layer having a peripheral portion coupled to the first layer; a first compartment defined by the second layer and a first portion of the first layer, the first compartment having a U-shape; a second compartment defined by the second layer and a second portion of the first layer, wherein the second compartment is at least partially surrounded by the first compartment; an inlet in the first layer, the inlet fluidly coupled to the second compartment; an outlet in the first layer, the outlet fluidly coupled to the first compartment; and a filler disposed in the first compartment, the filler disposed between the second layer and the outlet.

2. The flexible fluid storage pouch of claim 1, wherein the first layer comprises a polymer film.

3. The flexible fluid storage pouch of any of claims 1-2, wherein the first layer has a first peripheral portion and a second peripheral portion and wherein the first peripheral portion is coupled to the second peripheral portion.

4. The flexible fluid storage pouch of claim 3, wherein the first layer comprises a fold between the first peripheral portion and the second peripheral portion.

5. The flexible fluid storage pouch of any of claims 1-4, wherein the second layer comprises a polymer film and one or more filters, the filters configured to prevent liquid from passing from the second compartment to the first compartment.

6. The flexible fluid storage pouch of claim 5, wherein the second layer comprises at least one comer region and a filter of the one or more filters positioned proximate to each comer region.

7. The flexible fluid storage pouch of any of claims 5-6, wherein the second layer comprises a first region, a second region, and a fold between the first region and the second region.

8. The flexible fluid storage pouch of claim 7, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is positioned in the first region and the second filter is positioned in the first region.

9. The flexible fluid storage pouch of claim 8, wherein at least a portion of the second compartment is between the first filter and the second filter.

10. The flexible fluid storage pouch of claim 5, wherein the pouch has a first side and a second side opposite the first side.

11. The flexible fluid storage pouch of claim 10, wherein the inlet is proximate to the first side of the pouch and the outlet is proximate to the second side of the pouch.

12. The flexible fluid storage pouch of any of claims 10-11, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is proximate to the first side of the pouch and the second filter is proximate to the second side of the pouch.

13. The flexible fluid storage pouch of any of claims 1-4, wherein the second layer comprises a filter material configured to prevent liquid from passing from the second compartment to the first compartment.

14. The flexible fluid storage pouch of any of claims 1-13, wherein the filler comprises a manifold material.

15. The flexible fluid storage pouch of any of claims 1-13, wherein the filler comprises open-cell foam.

16. The flexible fluid storage pouch of claim 15, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

17. The flexible fluid storage pouch of any of claims 15-16, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

18. The flexible fluid storage pouch of any of claims 15-17, wherein the open-cell foam has about 120 to about 350 pores per inch.

19. The flexible fluid storage pouch of any of claims 15-18, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

20. The flexible fluid storage pouch of any of claims 1-19, wherein the filler is a first filler, the flexible fluid storage pouch further comprising a second filler disposed in the second compartment.

21. The flexible fluid storage pouch of claim 20, wherein the second filler comprises a manifold material.

22. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises closed-cell foam.

23. The flexible fluid storage pouch of claim 22, wherein the closed-cell foam is perforated.

24. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises a non- collapsible material having a plurality of perforations.

25. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises open-cell foam.

26. The flexible fluid storage pouch of claim 25, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

27. The flexible fluid storage pouch of any of claims 25-26, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

28. The flexible fluid storage pouch of any of claims 25-27, wherein the open-cell foam has about 120 to about 350 pores per inch.

29. The flexible fluid storage pouch of any of claims 25-28, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

30. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises a polymer lattice structure.

31. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises one or more foam spheres.

32. The flexible fluid storage pouch of any of claims 20-31, wherein the second fdler comprises a gelling material.

33. The flexible fluid storage pouch of any of claims 20-32, wherein the second fdler comprises an absorptive material.

34. The flexible fluid storage pouch of claim 20, wherein the second fdler comprises a manifold material having a serpentine shape having one or more layers.

35. The flexible fluid storage pouch of claim 34, wherein the second fdler further comprises an absorbent layer between one or more of the layers.

36. The flexible fluid storage pouch of any of claims 34-35, wherein the second fdler further comprises a wicking layer between one or more of the layers.

37. The flexible fluid storage pouch of claim 34, wherein the second fdler further comprises an absorbent layer and a wicking layer in a stacked relationship between one or more of the layers.

38. The flexible fluid storage pouch of any of claims 1-37, further comprising a charcoal fdter fluidly coupled to the outlet.

39. The flexible fluid storage pouch of any of claims 1-38, further comprising a check valve fluidly coupled to the inlet to prevent liquid from exiting the second compartment through the inlet.

40. The flexible fluid storage pouch of any of claims 1-39, further comprising a first fluid conductor coupled to the inlet, the first fluid conductor configured to be fluidly coupled to a tissue site.

41. The flexible fluid storage pouch of any of claims 1-40, further comprising a second fluid conductor coupled to the outlet, the second fluid conductor configured to be fluidly coupled to a negative-pressure source.

42. A method of manufacturing a flexible fluid storage pouch, the method comprising: forming a stack comprising: a first layer, including a first aperture and a second aperture; a second layer; and a filler between the first layer and the second layer; coupling the second layer to the first layer to form a first seal and a first compartment containing the filler, wherein the second aperture is fluidly coupled to the first compartment; folding the stack along a fold line into a U-shaped stack, wherein the second layer is on the inside of the U-shaped stack; and coupling the stack to itself to form a second seal and a second compartment, wherein the first aperture is fluidly coupled to the second compartment.

43. The method of claim 42, wherein the first layer has a first surface area and the second layer has a second surface area, the first surface area larger than the second surface area.

44. The method of any of claims 42-43, wherein the first layer comprises a polymer film.

45. The method of any of claims 42-44, wherein the second layer comprises a polymer film and one or more filters, the filters configured to prevent liquid from passing from the second compartment to the first compartment.

46. The method of claim 45, wherein the second layer comprises at least one comer region and a filter of the one or more filters positioned proximate to each comer region.

47. The method of any of claims 45-46, wherein the second layer comprises a first region, a second region, and a fold between the first region and the second region.

48. The method of claim 47, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is positioned in the first region and the second filter is positioned in the first region.

49. The method of claim 48, wherein at least a portion of the second compartment is between the first filter and the second filter.

50. The method of claim 45, wherein the second compartment has a first side and a second side opposite the first side.

51. The method of claim 50, wherein the first aperture is proximate to the first side of the second compartment and the second aperture is proximate to the second side of the second compartment.

52. The method of any of claims 50-51, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is proximate to the first side of the second compartment and the second filter is proximate to the second side of the second compartment.

53. The method of any of claims 42-44, wherein the second layer comprises a filter material configured to prevent liquid from passing from the second compartment to the first compartment.

54. The method of any of claims 42-53, wherein the filler comprises a manifold material.

55. The method of any of claims 42-53, wherein the filler comprises open-cell foam.

56. The method of claim 55, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

57. The method of any of claims 55-56, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

58. The method of any of claims 55-57, wherein the open-cell foam has about 120 to about 350 pores per inch.

59. The method of any of claims 55-58, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

60. The method of any of claims 42-59, wherein the filler is a first filler, the method further comprising inserting a second filler on the inside of the U-shaped stack.

61. The method of claim 60, wherein the second fdler comprises a manifold material.

62. The method of claim 60, wherein the second fdler comprises closed-cell foam.

63. The method of claim 62, wherein the closed-cell foam is perforated.

64. The method of claim 60, wherein the second fdler comprises a non-collapsible material having a plurality of perforations.

65. The method of claim 60, wherein the second fdler comprises open-cell foam.

66. The method of claim 65, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

67. The method of any of claims 65-66, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

68. The method of any of claims 65-67, wherein the open-cell foam has about 120 to about 350 pores per inch.

69. The method of any of claims 65-68, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

70. The method of claim 60, wherein the second fdler comprises a polymer lattice structure.

71. The method of claim 60, wherein the second fdler comprises one or more foam spheres.

72. The method of any of claims 60-71, wherein the second fdler comprises a gelling material.

73. The method of any of claims 60-72, wherein the second fdler comprises an absorptive material.

74. The method of claim 60, wherein the second fdler comprises a manifold material having a serpentine shape forming one or more gaps between the manifold material.

75. The method of claim 74, wherein the second fdler further comprises an absorbent layer in one or more of the gaps.

76. The method of any of claims 74-75, wherein the second fdler further comprises a wicking layer in one or more of the gaps.

77. The method of claim 74, wherein the second fdler further comprises an absorbent layer and a wicking layer in a stacked relationship in one or more of the gaps.

78. The method of any of claims 42-77, further comprising a charcoal filter fluidly coupled to the second aperture.

79. The method of any of claims 42-78, further comprising a check valve fluidly coupled to the first aperture to prevent liquid from exiting the second compartment through the first aperture.

80. The method of any of claims 42-79, further comprising a first fluid conductor coupled to the first aperture, the first fluid conductor configured to be fluidly coupled to a tissue site.

81. The method of any of claims 42-80, further comprising a second fluid conductor coupled to the second aperture, the second fluid conductor configured to be fluidly coupled to a negative- pressure source.

82. A fluid storage pouch comprising: a flexible envelope defining an interior space; a filter layer disposed in the interior space and coupled to the flexible envelope; a first compartment defined by the a first portion of the flexible envelope and the filter layer; a second compartment defined by a second portion of the flexible envelope and the filter layer; wherein the second compartment is partially surrounded by the first compartment; an inlet in the flexible envelope, the inlet fluidly coupled to the second compartment; an outlet in the flexible envelope, the outlet fluidly coupled to the first compartment; and a filler disposed in the first compartment, the filler disposed between the filter layer and the outlet.

83. The fluid storage pouch of claim 82, wherein the flexible envelope comprises one or more polymer films.

84. The fluid storage pouch of any of claims 82-83, wherein the filter layer comprises a polymer film and one or more filters, the filters configured to prevent liquid from passing from the second compartment to the first compartment.

85. The fluid storage pouch of claim 84, wherein the filter layer comprises at least one comer region and a filter of the one or more filters positioned proximate to each comer region.

86. The fluid storage pouch of any of claims 84-85, wherein the filter layer comprises a first region, a second region, and a fold between the first region and the second region.

87. The fluid storage pouch of claim 86, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is positioned in the first region and the second filter is positioned in the first region.

88. The fluid storage pouch of claim 87, wherein at least a portion of the second compartment is between the first filter and the second filter.

89. The fluid storage pouch of claim 84, wherein the second compartment has a first side and a second side opposite the first side.

90. The fluid storage pouch of claim 89, wherein the inlet is proximate to the first side of the second compartment and the outlet is proximate to the second side of the second compartment.

91. The fluid storage pouch of any of claims 89-90, wherein the one or more filters comprise a first filter and a second filter, wherein the first filter is proximate to the first side of the second compartment and the second filter is proximate to the second side of the second compartment.

92. The fluid storage pouch of any of claims 82-83, wherein the filter layer comprises a filter material configured to prevent liquid from passing from the second compartment to the first compartment.

93. The fluid storage pouch of any of claims 82-92, wherein the filler comprises a manifold material.

94. The fluid storage pouch of any of claims 82-92, wherein the filler comprises open-cell foam.

95. The fluid storage pouch of claim 94, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

96. The fluid storage pouch of any of claims 94-95, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

97. The fluid storage pouch of any of claims 94-96, wherein the open-cell foam has about 120 to about 350 pores per inch.

98. The fluid storage pouch of any of claims 94-97, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

99. The fluid storage pouch of any of claims 82-98, wherein the filler is a first filler, the fluid storage pouch further comprising a second filler disposed in the second compartment.

100. The fluid storage pouch of claim 99, wherein the second filler comprises a manifold material.

101. The fluid storage pouch of claim 99, wherein the second filler comprises closed-cell foam.

102. The fluid storage pouch of claim 101, wherein the closed-cell foam is perforated.

103. The fluid storage pouch of claim 99, wherein the second fdler comprises a non-collapsible material having a plurality of perforations.

104. The fluid storage pouch of claim 99, wherein the second fdler comprises open-cell foam.

105. The fluid storage pouch of claim 104, wherein the open-cell foam has a density in a range of about 3.9 to about 14.7 lb/ft³.

106. The fluid storage pouch of any of claims 104-105, wherein the open-cell foam has a free volume in a range of about 13% to about 30%.

107. The fluid storage pouch of any of claims 104-106, wherein the open-cell foam has about 120 to about 350 pores per inch.

108. The fluid storage pouch of any of claims 104-107, wherein the open-cell foam has an average pore size in a range of about 57 to about 300 microns.

109. The fluid storage pouch of claim 99, wherein the second fdler comprises a polymer lattice structure.

110. The fluid storage pouch of claim 99, wherein the second fdler comprises one or more foam spheres.

111. The fluid storage pouch of any of claims 99-110, wherein the second fdler comprises a gelling material.

112. The fluid storage pouch of any of claims 99-111, wherein the second fdler comprises an absorptive material.

113. The fluid storage pouch of claim 99, wherein the second fdler comprises: a manifold material having a serpentine shape forming one or more gaps between the manifold material.

114. The fluid storage pouch of claim 113, wherein the second fdler further comprises an absorbent layer in one or more of the gaps.

115. The fluid storage pouch of any of claims 113-114, wherein the second fdler further comprises a wicking layer in one or more of the gaps.

116. The fluid storage pouch of claim 113, wherein the second fdler further comprises an absorbent layer and a wicking layer in a stacked relationship in one or more of the gaps.

117. The fluid storage pouch of any of claims 82-116, further comprising a charcoal fdter fluidly coupled to the outlet.

118. The fluid storage pouch of any of claims 82-117, further comprising a check valve fluidly coupled to the inlet to prevent liquid from exiting the second compartment through the inlet.

119. The fluid storage pouch of any of claims 82-118, further comprising a first fluid conductor coupled to the inlet, the first fluid conductor configured to be fluidly coupled to a tissue site.

120. The fluid storage pouch of any of claims 82-119, further comprising a second fluid conductor coupled to the outlet, the second fluid conductor configured to be fluidly coupled to a negative- pressure source.

121. The systems, apparatuses, and methods substantially as described herein.