Dressing and therapy system for exudate management

Abstract

A dressing for negative pressure wound therapy (NPWT) of a wound is provided. The dressing includes a dressing. The dressing includes a manifold adapted to be positioned adjacent to the wound for receiving negative pressure. The dressing further includes a base foam disposed on the manifold. The dressing further includes an accumulation chamber defined in the base foam and configured to be disposed in fluid communication with an outlet of a negative pressure source. The dressing further includes a top foam disposed on the base foam. The dressing further includes a pre-canister defined in the top foam and configured to be disposed in fluid communication with the manifold and the accumulation chamber. The pre-canister is configured to receive pressurized air from the accumulation chamber when the negative pressure source is in an off state, thereby purging the pre-canister by allowing exudate flow from the pre-canister to a final canister.

Description

[0001] PA100050W002

[0002] DRESSING AND THERAPY SYSTEM FOR EXUDATE MANAGEMENT

[0003] Cross-Reference to Related Applications

[0004] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 707,901, filed on October 16, 2024, which is incorporated herein by reference in its entirety.

[0005] Technical Field

[0006] The present disclosure relates generally to exudate management in negative pressure wound therapy. More particularly, the present disclosure relates to a dressing and a therapy system for negative pressure wound therapy and exudate management in negative pressure wound therapy.

[0007] Background

[0008] Negative pressure wound therapy (NPWT) systems are embodied as sealed wound-care systems particularly indicated for chronic persistent wounds and / or complicated wounds. Specifically, for promoting wound healing, a pressure that is reduced relative to the surroundings (commonly referred to as “negative pressure”) is applied to the wound. The negative pressure causes mechanical contraction of the wound and removal of exudates, such as, slough, necrotic tissue, microbial load (e.g., bacteria and biofdms) from the wound, thus promoting formation of granulation tissues and accelerating wound healing.

[0009] The reduced pressure in proximity to the wound site may be applied via an NPWT system including a dressing. Conventional NPWT systems store exudate in rigid canisters connected to a pump (negative pressure source) or within super absorbents in the dressing. Large size pump mounted rigid canisters may negatively affect patient comfort and therapy compliance. Super absorbent dressings may swell up when exudate is absorbed which may further occlude the negative pressure flow path. This may result in loss of negative pressure therapy at the wound as well as holding fluid onto the patient’s skin. Super absorbent dressings must rely solely on evaporation to reduce housed exudate volume. Due to such issues, healing outcome may be affected with unreliable negative pressure applied to the wound.

[0010] Summary

[0011] In a first aspect, the present disclosure provides a dressing for negative pressure wound therapy of a wound on a skin. The dressing includes a manifold adapted to be positioned adjacent to the wound for receiving negative pressure. The manifold is in fluid communication with a negative pressure source to provide negative pressure to the wound. The negative pressure source includes an inlet and an outlet. The negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet. The dressing further includes a base foam disposed on the manifold. The dressing further includes an accumulation chamber defined in the base foam and configured to be disposed in fluid communication with the outlet. The accumulation chamber is configured to capture air at positive pressure from the outlet when the negative pressure source is in an on state. The dressing further includes a top foam disposed on the base foam. The dressing further includes a pre-canister defined in the top foam and configured to be disposed in fluid communication with the manifold and the accumulation chamber. The pre-canister is disposed in direct fluid communication with the inlet. The pre-canister is configured to collect exudate from the wound upon application of negative pressure to the wound. The pre-canister is configured to receive pressurized air from the accumulation chamber when the negative pressure source is in an off state, thereby purging the pre-canister by allowing exudate flow from the pre-canister to a final canister. The dressing further includes an intermediate film disposed between the top foam and the base foam. The intermediate fdm is configured to allow exudate flow between the manifold and the pre-canister when the negative pressure source is in the on state. The intermediate film is further configured to allow air flow between the accumulation chamber and the pre-canister when the negative pressure source is in the off state. The intermediate film is further configured to allow purging the pre-canister when the negative pressure source is in the off state.

[0012] In a second aspect, the present disclosure provides a therapy system for negative pressure wound therapy of a wound on a skin. The therapy system includes the dressing of the first aspect. The therapy system further includes a negative pressure source disposed in fluid communication with the manifold to provide negative pressure to the wound. The negative pressure source includes an inlet and an outlet. The negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet.

[0013] In a third aspect, the present disclosure provides a dressing for negative pressure wound therapy of a wound on a skin. The dressing includes a first manifold adapted to be positioned adjacent to the wound for receiving negative pressure. The first manifold is in fluid communication with a negative pressure source to provide negative pressure to the wound. The negative pressure source includes an inlet and an outlet. The negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet. The dressing further includes a second manifold disposed on the first manifold for receiving positive pressure from the outlet. The second manifold is in fluid communication with the negative pressure source. The dressing further includes a canister disposed proximal to the second manifold and distal to the first manifold. The canister includes a bottom surface and a top surface opposite to the bottom surface. The canister is in fluid communication with the second manifold. Upon application of negative pressure to the wound, the exudate is drawn from the wound through the first manifold; and the exudate drawn from the first manifold is pushed towards the canister through the second manifold. The exudate is pushed by the positive pressure received by the second manifold.

[0014] Brief Description of the Drawings

[0015] Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

[0016] FIG. 1 A is a schematic top view of a therapy system and a dressing thereof, wherein a negative pressure source is in an on state, according to an embodiment of the present disclosure;

[0017] FIG. IB is a schematic top view of the therapy system and the dressing of FIG. 1 A, wherein the negative pressure source is in an off state, according to an embodiment of the present disclosure;

[0018] FIG. 2A is a schematic side view of the dressing of FIG. 1A illustrating a first valve, wherein the negative pressure source is in the on state, according to an embodiment of the present disclosure;

[0019] FIG. 2B is a schematic side view of the dressing of FIG. 2A, wherein the negative pressure source is in the off state, according to an embodiment of the present disclosure;

[0020] FIG. 3A is a schematic side view of the dressing of FIG. 1A illustrating a second valve, wherein the negative pressure source is in the on state, according to an embodiment of the present disclosure;

[0021] FIG. 3B is a schematic side view of the dressing of FIG. 3A, wherein the negative pressure source is in the off state, according to an embodiment of the present disclosure;

[0022] FIG. 4A is a schematic side view of the dressing of FIG. 1A illustrating a third valve, wherein the negative pressure source is in the on state, according to an embodiment of the present disclosure;

[0023] FIG. 4B is a schematic side view of the dressing of FIG. 4A, wherein the negative pressure source is in the off state, according to an embodiment of the present disclosure;

[0024] FIG. 5 is a schematic top view of a therapy system and a dressing thereof, according to another embodiment of the present disclosure;

[0025] FIG. 6A is a schematic top view of a dressing, according to another embodiment of the present disclosure;

[0026] FIG. 6B is a schematic side view of the dressing of FIG. 6 A, with some components not shown, according to an embodiment of the present disclosure;

[0027] FIG. 7A is a schematic top view of a dressing, according to another embodiment of the present disclosure; and

[0028] FIG. 7B is a schematic side view of the dressing of FIG. 7A, according to an embodiment of the present disclosure.

[0029] Detailed Description

[0030] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0031] In the following disclosure, the following definitions are adopted.

[0032] As recited herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0033] The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0034] The term “about”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0035] Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

[0036] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be constmed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0037] As used herein, when a first material is termed as “same” or “similar” as a second material, at least 90 weight % of the first and second materials are identical and any variation between the first and second materials comprises less than about 10 weight % of each of the first and second materials.

[0038] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.

[0039] Unless specified or limited otherwise, the terms “attached,” “connected,” “coupled”, and variations thereof, are used broadly and encompass both direct physical connections, or indirect physical connections between two or more components that are connected together by one or more additional components. For example, a first component may be coupled to a second component by being directly connected together or by being connected by a third component. In some examples, coupling, connection, and attachment may also include mechanical, thermal, electrical, or chemical coupling (such as a chemical bond) in some contexts.

[0040] As used herein, the terms “layer,” “sheet,” and “dressing,” or variations thereof, are used to describe an article having a thickness that is small relative to its length and width.

[0041] As used herein, the term “negative pressure” broadly refers to a pressure lower than a local ambient pressure, such as an ambient pressure, in a local environment outside the sealed treatment environment provided by a dressing. In many cases, the local ambient pressure can also be the atmospheric pressure at which a wound site is located. Alternatively, the pressure can be less than the hydrostatic pressure associated with the tissue at the wound site. Unless otherwise specified, the pressure values described herein are gauge pressures. Similarly, a reference to an increase in negative pressure typically refers to a decrease in absolute pressure, while a decrease in negative pressure typically refers to an increase in absolute pressure.

[0042] As used herein, the term “wounds” may include, for example, chronic, acute, traumatic, subacute, closed surgical wounds or dehiscence wounds, partially thick bums, ulcers (such as, diabetic, compressive, or venous insufficiency ulcers), flaps, and grafts. The wound may also include an open abdomen area of a patient.

[0043] As used herein, the term “wound site” may include a tissue site, such as, bone tissue, adipose tissue, muscle tissue, nerve tissue, skin tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. The term “wound site” may also refer to an area of a tissue that is not necessarily a wound or a defect but may be desired to add or promote additional tissue growth. For example, negative pressure therapy can be used in a particular tissue area to grow additional tissue that can be harvested or transplanted to another tissue site. The wound site may also include an area wherein a surgical incision has been previously performed.

[0044] As used herein, when the term "fluid impermeable" is used to describe a layer or laminate, it means that a fluid, such as water or body fluid, will not substantially pass through the layer or laminate under the conditions of use.

[0045] The present disclosure provides a dressing for negative pressure wound therapy (NPWT) of a wound on a skin. The dressing includes a manifold adapted to be positioned adjacent to the wound for receiving negative pressure. The manifold is in fluid communication with a negative pressure source to provide negative pressure to the wound. The negative pressure source includes an inlet and an outlet. The negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet. The dressing further includes a base foam disposed on the manifold. The dressing further includes an accumulation chamber defined in the base foam and configured to be disposed in fluid communication with the outlet. The accumulation chamber is configured to capture air at positive pressure from the outlet when the negative pressure source is in an on state. The dressing further includes a top foam disposed on the base foam. The dressing further includes a pre-canister defined in the top foam and configured to be disposed in fluid communication with the manifold and the accumulation chamber. The pre-canister is disposed in direct fluid communication with the inlet. The pre-canister is configured to collect exudate from the wound upon application of negative pressure to the wound. The pre-canister is configured to receive pressurized air from the accumulation chamber when the negative pressure source is in an off state, thereby purging the pre-canister by allowing exudate flow from the pre-canister to a final canister. The dressing further includes an intermediate film disposed between the top foam and the base foam. The intermediate film is configured to allow exudate flow between the manifold and the pre-canister when the negative pressure source is in the on state. The intermediate film is further configured to allow air flow between the accumulation chamber and the pre-canister when the negative pressure source is in the off state. The intermediate film is further configured to allow purging the pre-canister when the negative pressure source is in the off state. The present disclosure further provides a therapy system for negative pressure wound therapy of a wound on a skin. The therapy system includes the dressing and a negative pressure source disposed in fluid communication with the manifold to provide negative pressure to the wound. The negative pressure source includes an inlet and an outlet. The negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet.

[0046] As the dressing and the therapy system of the present disclosure do not use any large sized rigid canister (connected to negative pressure source) for storing the exudate, there is improved patient comfort and therapy compliance as compared to conventional NPWT systems where large sized rigid canisters are used for storing the exudate which could impact patient comfort and therapy compliance. Therefore, by including the accumulation chamber and the pre-canister in the dressing, the exudate can be stored on the dressing and the pre-canister can be purged easily while applying continuous negative pressure to the wound. Further, the exudate can be managed without swollen super absorbent occluding the flow path. This eliminates the problem of loss of negative pressure therapy at the wound and the fluid does not hold onto the patient’s skin. Hence, the dressing and the therapy system of the present disclosure may provide improved comfort as well as improved healing for the patient.

[0047] In some embodiments, the therapy system may be designed to allow for drainage of stored exudate. Moreover, the negative pressure source may be kept to a minimal size, thereby increasing patient comfort. For example, the negative pressure source may be a micro pump mounted on the dressing or remote from the dressing.

[0048] Referring now to Figures, FIG. 1 A is a schematic top view of a therapy system 50 and a dressing 100 thereof for negative pressure wound therapy (NPWT) of a wound 52 on a skin 54 (shown in FIG. 2A), according to an embodiment of the present disclosure. The therapy system 50 is used for treating the wound 52 that may extend through the skin 54 (epidermis or dermis). Further, the wound 52 may be a bodily tissue of any human, animal, or other organism, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligaments, or any other tissue. Treatment of the wound 52 may include removal of fluids, e.g., exudate or ascites.

[0049] The therapy system 50 includes the dressing 100 and a negative pressure source 56 to supply negative pressure to the dressing 100 and the wound 52. The negative pressure source 56 may be a reservoir of air at a negative pressure or may be a manual or electrically powered device. In some embodiments, the negative pressure source 56 is a vacuum pump, a suction pump, or a wall suction port available at many healthcare facilities. In the illustrated embodiment of FIG. 1A, the negative pressure source 56 is remote from the dressing 100.

[0050] “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 56 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).

[0051] In FIG. 1A, the negative pressure source 56 is in an on state SI and the negative pressure is being applied to the dressing 100. FIG. IB is a schematic top view of the therapy system 50 and the dressing 100 of FIG. 1A, wherein the negative pressure source 56 is in an off state S2, according to an embodiment of the present disclosure. FIG. 2A is a schematic side view of the dressing 100 of FIG. 1A, wherein the negative pressure source 56 is in the on state SI, according to an embodiment of the present disclosure. The negative pressure source 56 is not shown in FIG. 2A for illustrative purposes.

[0052] Referring to FIGS. 1 A to 2A, the negative pressure source 56 includes an inlet 58 and an outlet 60. The negative pressure source 56 is configured to generate negative pressure at the inlet 58 and positive pressure at the outlet 60. The dressing 100 includes a manifold 102 (shown in FIG. 2A) adapted to be positioned adjacent to the wound 52 for receiving negative pressure. The manifold 102 is in fluid communication with the negative pressure source 56 to provide negative pressure to the wound 52. In other words, the negative pressure source 56 is disposed in fluid communication with the manifold 102 to provide negative pressure to the wound 52 for NPWT of the wound 52. Specifically, the manifold 102 is configured to be fluidly communicated with the negative pressure source 56 through a conduit 62 and a fluid connector (not shown). The conduit 62 is connected to a socket 64 provided in the dressing 100.

[0053] The manifold 102 may be adapted to be positioned proximate to or adjacent to the wound 52, such as, for example, by cutting or otherwise shaping the manifold 102 in any suitable manner to fit the wound 52. The manifold 102 may be adapted to be positioned in fluid communication with the wound 52 to distribute reduced pressure to the wound 52. In some embodiments, the manifold 102 may be positioned in direct contact with the wound 52. The manifold 102 may be formed from any manifold material or flexible bolster material that provides a vacuum space, or treatment space, such as, for example, a porous and permeable foam or foam-like material, a member formed with pathways, a graft, or a gauze. As a more specific, non-limiting example, the manifold 102 may be a reticulated, open-cell polyurethane or poly ether foam that allows good permeability of fluids while under a reduced pressure. One such foam material is the VAC® GranuFoam® material available from Kinetic Concepts, Inc. (KCI) of San Antonio, Tex. Any material or combination of materials may be used as a manifold material for the manifold 102 provided that the manifold material is operable to distribute or collect fluid. For example, herein the term manifold may refer to a substance or structure that is provided to assist in delivering fluids to or removing fluids from a tissue site through a plurality of pores, pathways, or flow channels. The plurality of pores, pathways, or flow channels may be interconnected to improve distribution of fluids provided to and removed from an area around the manifold. Examples of manifolds may include, without limitation, devices that have structural elements arranged to form flow channels, cellular foam, such as open-cell foam, porous tissue collections, and liquids, gels, and foams that include or cure to include flow channels.

[0054] A material with a higher or lower density than GranuFoam® material may be desirable for the manifold 102 depending on the application. Among the many possible materials, the following may be used: GranuFoam® material, Foamex® technical foam (www.foamex.com), a molded bed of nails structures, a patterned grid material such as those manufactured by Sercol Industrial Fabrics, 3D textiles such as those manufactured by Baltex of Derby, U.K., a gauze, a flexible channel-containing member, a graft, etc. In some instances, ionic silver may be added to the manifold 102 by, for example, a micro bonding process. Other substances, such as anti-microbial agents, may be added to the manifold 102 as well.

[0055] In some embodiments, the manifold 102 may comprise a porous, hydrophobic material. The hydrophobic characteristics of the manifold 102 may prevent the manifold 102 from directly absorbing fluid, such as exudate, from the wound 52, but allow the fluid to pass through. The dressing 100 may be adapted to provide negative pressure from the negative pressure source 56 to the manifold 102, and to store fluid (exudate) extracted from the wound 52 through the manifold 102.

[0056] The dressing 100 further includes a base foam 104 disposed on the manifold 102. In some embodiments, the dressing 100 further includes abase film 106 disposed between the manifold 102 and the base foam 104. The base film 106 includes an adhesive to adhesively bond the dressing 100 to the skin 54. The base film 106 may be an adhesive layer to bond the dressing 100 to the skin 54. The base film 106 may be a soft, pliable material suitable for providing a fluid seal with the wound 52. For example, the base film 106 may comprise a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gels, a foamed gel, a soft closed cell foam such as polyurethanes and polyolefins coated with an adhesive.

[0057] The dressing 100 further includes a top foam 108 disposed on the base foam 104. The dressing 100 further includes an intermediate film 110 disposed between the top foam 108 and the base foam 104. The dressing 100 further includes a top film 112 disposed adjacent to the top foam 108, such that the top foam 108 is sandwiched between the top film 112 and the intermediate film 110. The top film 112 is a drape adapted to provide a fluid seal over the wound 52. The top film 112 includes an adhesive to adhesively bond with the top foam 108.

[0058] In some example embodiments, the top film 112 may be a polymer drape, such as a polyurethane fdm, 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 top film 112 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 fdms, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the top film 112 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g / m2 / 24 hours and a thickness of about 30 microns.

[0059] The dressing 100 further includes an accumulation chamber 114 defined in the base foam 104 and configured to be disposed in fluid communication with the outlet 60. As illustrated in FIG. 1 A, the accumulation chamber 114 is configured to capture air at positive pressure from the outlet 60 when the negative pressure source 56 is in the on state SI. In some embodiments, the dressing 100 further includes a check valve V4 positioned in the base foam 104 and between the outlet 60 and the accumulation chamber 114 to prevent backflow of air from the accumulation chamber 114 to the outlet 60. In some embodiments, the check valve V4 is a flapper type valve. As illustrated in FIG. 1A, the check valve V4 allows air flow AF from the outlet 60 to the accumulation chamber 114.

[0060] The dressing 100 further includes a pre-canister 116 defined in the top foam 108 and configured to be disposed in fluid communication with the manifold 102 and the accumulation chamber 114. The pre-canister 116 is further disposed in direct fluid communication with the inlet 58 and configured to collect exudate from the wound 52 upon application of negative pressure to the wound 52. As illustrated in FIGS. 1A and 2A, when the negative pressure source 56 is in the on state SI to apply negative pressure to the wound 52, the pre-canister 116 collects exudate from the wound 52 via the manifold 102. Exudate flow EF is illustrated in FIG. 1A. The intermediate film 110 is configured to allow exudate flow EF between the manifold 102 and the pre-canister 116 when the negative pressure source 56 is in the on state SI.

[0061] With continued reference to FIGS. 1A to 2A, the dressing 100 further includes a first valve VI configured to fluidly communicate the manifold 102 and the pre-canister 116. The first valve VI is defined at least by the intermediate film 110. In some embodiments, the first valve VI is defined in the top foam 108 and the intermediate film 110. FIG. 2A is the schematic side view of the dressing 100 illustrating the first valve V 1 , wherein the negative pressure source 56 is in the on state S 1. FIG. 2B is the schematic side view of the dressing 100 illustrating the first valve VI, wherein the negative pressure source 56 is in the off state S2. The first valve VI is a one-way valve. The negative pressure source 56 is not shown in FIGS. 2A and 2B for illustrative purposes. As illustrated in FIGS. 1A and 2A, when the negative pressure source 56 is in the on state SI, the first valve VI is open, thereby allowing exudate flow EF from the manifold 102 to the pre-canister 116. In other words, during a phase of cycle where negative pressure is being delivered by the negative pressure source 56, the first valve VI may remain in an open position, thereby allowing fluid communication between the manifold 102 and the pre-canister 116. As illustrated in FIGS. IB and 2B, when the negative pressure source 56 is in the off state S2, the first valve VI is closed, thereby preventing exudate flow EF from the manifold 102 to the pre-canister 116. In other words, during a phase of cycle where negative pressure is not being delivered by the negative pressure source 56, the first valve VI may remain in a closed position, thereby minimizing or preventing fluid communication between the manifold 102 and the pre-canister 116.

[0062] The first valve VI includes a first disc portion 118 defined in the intermediate film 110 and adjacent to an opening 120 in the intermediate film 110. The opening 120 is in fluid communication with the pre-canister 116. The first disc portion 118 is movable between a rest position Pl (shown in FIG. 2B) and a lifted position P2 (shown in FIG. 2A). The first disc portion 118 prevents fluid communication between the manifold 102 and the opening 120 in the rest position Pl. The first disc portion 118 allows fluid communication between the manifold 102 and the opening 120 in the lifted position P2.

[0063] The first valve VI further includes a first compressible member 122 placed on the opening 120 and the first disc portion 118, such that the first compressible member 122 is movable between an expanded position P3 (shown in FIG. 2B) and a compressed position P4 (shown in FIG. 2A). The first compressible member 122 is biased towards the expanded position P3. The first disc portion 118 is in the rest position Pl when the first compressible member 122 is in the expanded position P3. The first disc portion 118 is in the lifted position P2 when the first compressible member 122 is in the compressed position P4. In some embodiments, the first compressible member 122 is placed in the top foam 108. In some embodiments, the first compressible member 122 is bonded to the first disc portion 118. In some embodiments, the first compressible member 122 is an open cell foam. In some embodiments, the first compressible member 122 includes a polyurethane foam.

[0064] As illustrated in FIGS. IB and 2B, when the negative pressure source 56 is in the off state S2, the first compressible member 122 is in the expanded position P3 and the first disc portion 118 is in the rest position Pl, thereby preventing exudate flow EF from the manifold 102 to the opening 120 and further to the pre-canister 116.

[0065] As illustrated in FIGS. 1A and 2A, when the negative pressure source 56 is in the on state SI, the first disc portion 118 moves from the rest position Pl to the lifted position P2, and the first compressible member 122 moves from the expanded position P3 to the compressed position P4, thereby allowing exudate flow EF from the manifold 102 to the opening 120 and further to the pre-canister 116.

[0066] The pre-canister 116 is configured to receive pressurized air from the accumulation chamber 114 when the negative pressure source 56 is in the off state S2. The intermediate film 110 is configured to allow air flow AF between the accumulation chamber 114 and the pre-canister 116 when the negative pressure source 56 is in the off state S2.

[0067] Referring again to FIGS. 1A and IB, the dressing 100 further includes a second valve V2 configured to fluidly communicate the accumulation chamber 114 and the pre-canister 116. The second valve V2 is defined at least by the intermediate film 110. In some embodiments, the second valve V2 is defined in the base foam 104 and the intermediate film 110. FIG. 3 A is a schematic side view of the dressing 100 illustrating the second valve V2, wherein the negative pressure source 56 is in the on state SI. FIG. 3B is the schematic side view of the dressing 100 illustrating the second valve V2, wherein the negative pressure source 56 is in the off state S2. The second valve V2 is a one-way valve. The negative pressure source 56 is not shown in FIGS. 3 A and 3B for illustrative purposes.

[0068] As illustrated in FIGS. 1A and 3A, when the negative pressure source 56 is in the on state SI, the second valve V2 is closed, thereby preventing air flow AF from the accumulation chamber 114 to the pre-canister 116. In other words, during a phase of cycle where negative pressure is being delivered by the negative pressure source 56, the second valve V2 may remain in a closed position, thereby preventing air communication between the accumulation chamber 114 and the pre-canister 116. As illustrated in FIGS. IB and 3B, when the negative pressure source 56 is in the off state S2, the second valve VI is open, thereby allowing air flow AF from the accumulation chamber 114 to the pre-canister 116 and further purging the pre-canister 116. In other words, during a phase of cycle where negative pressure is not being delivered by the negative pressure source 56, the second valve V2 may remain in an open position, thereby allowing air communication between the accumulation chamber 114 and the pre-canister 116.

[0069] The second valve V2 includes a second disc portion 124 defined in the intermediate film 110 and movable between a rest position P5 (shown in FIG. 3A) and a lifted position P6 (shown in FIG. 3B). The second disc portion 124 prevents fluid communication between the accumulation chamber 114 and the pre-canister 116 in the rest position P5. The second disc portion 124 allows fluid communication between the accumulation chamber 114 and the pre-canister 116 in the lifted position P6.

[0070] The second valve V2 further includes a second compressible member 126 placed on the second disc portion 124, such that the second compressible member 126 is movable between an expanded position P7 (shown in FIG. 3A) and a compressed position P8 (shown in FIG. 3B). The second compressible member 126 is biased towards the expanded position P7. The second disc portion 124 is in the rest position P5 when the second compressible member 126 is in the expanded position P7. The second disc portion 124 is in the lifted position P6 when the second compressible member 126 is in the compressed position P8. In some embodiments, the second compressible member 126 is placed in the base foam 104. In some embodiments, the second compressible member 126 is bonded to the second disc portion 124. In some embodiments, the second compressible member 126 is an open cell foam. In some embodiments, the second compressible member 126 includes a polyurethane foam. As illustrated in FIGS. 1A and 3A, when the negative pressure source 56 is in the on state SI, the second compressible member 126 is in the expanded position P7 and the second disc portion 124 is in the rest position P5, thereby preventing air flow AF from the accumulation chamber 114 to the precanister 116.

[0071] As illustrated in FIGS. IB and 3B, when the negative pressure source 56 is in the off state S2, the second disc portion 124 moves from the rest position P5 to the lifted position P6, and the second compressible member 126 moves from the expanded position P7 to the compressed position P8, thereby opening an air passage 128 to allow air flow AF from the accumulation chamber 114 to the pre-canister 116. When the second compressible member 126 moves from the expanded position P7 to the compressed position P8, the air passage 128 is formed between the intermediate film 110 and the top foam 108.

[0072] Referring again to FIGS. 1A and IB, the dressing 100 further includes a third valve V3 configured to fluidly communicate the pre-canister 116 and a final canister 130 (shown in FIG. 4A). The third valve V3 is defined at least by the intermediate film 110. In some embodiments, the third valve V3 is defined in the base foam 104 and the intermediate film 110. FIG. 4 A is a schematic side view of the dressing 100 illustrating the third valve V3, wherein the negative pressure source 56 is in the on state SI. FIG. 4B is the schematic side view of the dressing 100 illustrating the third valve V3, wherein the negative pressure source 56 is in the off state S2. The third valve V3 is a one-way valve. The negative pressure source 56 is not shown in FIGS. 3A and 3B for illustrative purposes. In some embodiments, the final canister 130 is remote from the dressing 100. In some embodiments, the final canister 130 is integrated in the dressing 100.

[0073] As illustrated in FIGS. IB and 4B, when the negative pressure source 56 is in the off state S2, the third valve V3 is open, thereby allowing purging the pre-canister 116 and further allowing exudate flow EF from the pre-canister 116 to the final canister 130. In other words, during a phase of cycle where negative pressure is not being delivered by the negative pressure source 56, the third valve V3 may remain in an open position, thereby allowing fluid communication between the pre-canister 116 and the final canister 130. As illustrated in FIGS. 1 A and 4A, when the negative pressure source 56 is in the on state SI, the third valve V3 is closed, thereby preventing purging the pre-canister 116 and further preventing exudate flow EF from the pre-canister 116 to the final canister 130. In other words, during a phase of cycle where negative pressure is being delivered by the negative pressure source 56, the third valve V3 may remain in a closed position, thereby minimizing or preventing fluid communication between the pre-canister 116 and the final canister 130.

[0074] Therefore, referring to FIGS. 3A to 4B, the pre-canister 116 is configured to receive pressurized air from the accumulation chamber 114 when the negative pressure source 56 is in the off state S2, thereby purging the pre-canister 116 by allowing exudate flow EF from the pre-canister 116 to the final canister 130. As the third valve v3 is defined at least by the intermediate film 110, the intermediate film 110 is configured to allow purging the pre-canister 116 when the negative pressure source 56 is in the off state S2.

[0075] The third valve V3 includes a third disc portion 132 defined in the intermediate film 110 and movable between a rest position P9 (shown in FIG. 4A) and a lifted position PIO (shown in FIG. 4B). The third disc portion 132 prevents fluid communication between the pre-canister 116 and the final canister 130 in the rest position P9. The third disc portion 132 allows fluid communication between the pre-canister 116 and the final canister 130 in the lifted position PIO.

[0076] The third valve V3 further includes a third compressible member 134 placed on the third disc portion 132, such that the third compressible member 134 is movable between an expanded position Pl 1 (shown in FIG. 4A) and a compressed position P12 (shown in FIG. 4B). The third compressible member 134 is biased towards the expanded position Pl l. The third disc portion 132 is in the rest position P9 when the third compressible member 134 is in the expanded position Pl l. The third disc portion 132 is in the lifted position PIO when the third compressible member 134 is in the compressed position P12. In some embodiments, the third compressible member 134 is placed in the base foam 104. In some embodiments, the third compressible member 134 is bonded to the third disc portion 132. In some embodiments, the third compressible member 134 is an open cell foam. In some embodiments, the third compressible member 134 includes a polyurethane foam.

[0077] As illustrated in FIGS. 1A and 4A, when the negative pressure source 56 is in the on state SI, the third compressible member 134 is in the expanded position Pl l and the third disc portion 132 is in the rest position P9, thereby preventing purging the pre-canister 116 and further preventing exudate flow EF from the pre-canister 116 to the final canister 130.

[0078] As illustrated in FIGS. IB and 4B, when the negative pressure source 56 is in the off state S2, the third disc portion 132 moves from the rest position P9 to the lifted position P10, and the third compressible member 134 moves from the expanded position Pl l to the compressed position P12, opening a fluid passage 136 to allow purging the pre-canister 116 and further allow exudate flow EF from the pre-canister 116 to the final canister 130. When the third compressible member 134 moves from the expanded position Pl l to the compressed position P12, the fluid passage 136 is formed between the intermediate film 110 and the top foam 108.

[0079] Referring to FIGS. 1A to 4B, as the dressing 100 and the therapy system 50 do not use any large sized rigid canister (connected to the negative pressure source 56) for storing the exudate, there is improved patient comfort and therapy compliance as compared to conventional NPWT systems where large sized rigid canisters are used for storing the exudate which could impact patient comfort and therapy compliance. Therefore, by including the accumulation chamber 114 and the pre-canister 116 in the dressing 100, the exudate can be stored on the dressing 100 and the pre-canister 116 can be purged easily while applying continuous negative pressure to the wound 52. Further, the exudate can be managed without swollen super absorbent occluding the flow path. This eliminates the problem of loss of negative pressure therapy at the wound 52 and the fluid (exudate) does not hold onto the patient’s skin. Hence, the dressing 100 and the therapy system 50 may provide improved comfort as well as improved healing for the patient.

[0080] The inclusion of the first valve VI, the second valve V2, and the third valve V3 provides a desirable flow timing of air flow AF and exudate flow EF between various components within the dressing 100. In other words, these valves (i.e., the first valve VI, the second valve V2, and the third valve V3) may control timing of air flow AF between the accumulation chamber 114 and the precanister 116, exudate flow EF between the manifold 102 and the pre-canister 116, and exudate flow EF between the pre-canister 116 and the final canister 130. In some embodiments, the therapy system 50 may be designed to allow for drainage of stored exudate.

[0081] FIG. 5 is a schematic top view of a therapy system 50’ and a dressing 100’ thereof, according to another embodiment of the present disclosure. The dressing 100’ is substantially similar to the dressing 100 of FIGS. 1A and IB, with common components being referred to by the same numerals. However, in the therapy system 50’ and the dressing 100’, the negative pressure source 56 is integrated in the dressing 100’ (instead of being remote from the dressing 100). In some embodiments, the negative pressure source 56 is a micro pump mounted on the dressing 100’. Functional advantages of the dressing 100’ may be the same as those of the dressing 100.

[0082] FIG. 6 A is a schematic top view of a dressing 150, according to another embodiment of the present disclosure. FIG. 6B is a schematic side view of the dressing 150, with some components not shown. The dressing 150 is used for negative pressure wound therapy of the wound 52 on the skin 54 (also shown in FIG. 2A). The dressing 150 includes a first manifold 152 adapted to be positioned adjacent to the wound 52 for receiving negative pressure. The first manifold 152 has the same characteristics as that of the manifold 102 shown in FIG. 2A. The first manifold 152 is in fluid communication with the negative pressure source 56 (also shown in FIGS. 1A and IB) to provide negative pressure to the wound 52. Specifically, the first manifold 152 is configured to be fluidly communicated with the negative pressure source 56 through a conduit 62. As also illustrated in FIGS. 1 A and IB, the negative pressure source 56 includes the inlet 58 and the outlet 60. The negative pressure source 56 is not shown in FIG. 6B for illustrative purposes. The negative pressure source 56 is remote from the dressing 150.

[0083] The dressing 150 further includes a base layer 154 to adhesively bond the dressing 150 to the skin 54. The base layer 154 may include an adhesive to adhesively bond the dressing 150 to the skin 54. The dressing 150 further includes a second manifold 156 disposed on the first manifoldl52 for receiving positive pressure from the outlet 60. The second manifold 156 is in fluid communication with the negative pressure source 56. The second manifold 156 is configured to capture air at positive pressure from the outlet 60 when the negative pressure source 56 is applying negative pressure to the wound 52.

[0084] The dressing 150 further includes a canister 158 disposed proximal to the second manifold 156 and distal to the first manifold 152. The second manifold 156 is disposed between the first manifold 152 and the canister 158. The canister 158 is in fluid communication with the second manifold 156. The canister 158 includes a bottom surface 160 and a top surface 162 opposite to the bottom surface 160. In some embodiments, the canister 158 is adhesively bonded to the second manifold 156. In some embodiments, the dressing 150 further includes a releasable adhesive layer 164 to adhesively bond the canister 158 to the second manifold 156. In some embodiments, the canister 158 is made up of a transparent material.

[0085] Upon application of negative pressure to the wound 52, the exudate is drawn from the wound 52 through the first manifold 152. Further, the exudate drawn from the first manifold 152 is pushed towards the canister 158 through the second manifold 156. The exudate is pushed by the positive pressure received by the second manifold 156 from the outlet 60.

[0086] In some embodiments, the bottom surface 160 of the canister 158 includes one or more canister inlets 166 to allow exudate flow from the second manifold 156 to the canister 158. In some embodiments, the top surface 162 of the canister 158 includes a vent membrane 168 to allow air to escape from the canister 158 as positive pressure flows through the canister 158. In some embodiments, the canister 158 contains a super absorbent material to contain the exudate. In some embodiments, the canister 158 is made up of a transparent material. In some embodiments, the canister 158 includes volume indicators to assist in measuring or verifying volume of exudate inside the canister 158. In some embodiments, the canister 158 is made up of flexible plastic sheets which are sealed around their periphery. In some embodiments, the flexible plastic sheets include polyvinyl chloride, polyurethane, or similar flexible plastic sheet material.

[0087] As the dressing 150’ does not use any large sized rigid canister or a hard canister (connected to the negative pressure source 56) for storing the exudate, there is improved patient comfort and therapy compliance as compared to conventional NPWT systems where large sized rigid canisters are used for storing the exudate which could impact patient comfort and therapy compliance. Therefore, by including the second manifold 156 and a soft canister (i.e., the canister 158) in the dressing 150, the exudate can be stored on the dressing 150 and can be managed without swollen super absorbent occluding the flow path. This eliminates the problem of loss of negative pressure therapy at the wound 52 and the fluid (exudate) does not hold onto the patient’s skin. Hence, the dressing 150 may provide improved comfort as well as improved healing for the patient.

[0088] FIG. 7 A is a schematic top view of a dressing 150’, according to another embodiment of the present disclosure. FIG. 7B is a schematic side view of the dressing 150’, with some components not shown. The dressing 150’ is substantially similar to the dressing 150 of FIGS. 6A and 6B, with common components being referred to by the same numerals. However, in the embodiments illustrated in FIGS. 7A and 7B, the negative pressure source 56 is integrated in the dressing 150’ (instead of being remote from the dressing 150’). The dressing 150’ further includes a mounting pad 170 for mounting the negative pressure source 56 on the dressing 150’. The negative pressure source 56 includes a reservoir 172 for receiving the exudate from the first manifold 152 and supplying the same exudate to the second manifold 156. In some embodiments, the negative pressure source 56 is a micro pump or a peristaltic pump.

[0089] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0090] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

CLAIMS1. A dressing for negative pressure wound therapy of a wound on a skin, the dressing comprising: a manifold adapted to be positioned adjacent to the wound for receiving negative pressure, wherein the manifold is in fluid communication with a negative pressure source to provide negative pressure to the wound, the negative pressure source comprising an inlet and an outlet, the negative pressure source configured to generate negative pressure at the inlet and positive pressure at the outlet; a base foam disposed on the manifold; an accumulation chamber defined in the base foam and configured to be disposed in fluid communication with the outlet, wherein the accumulation chamber is configured to capture air at positive pressure from the outlet when the negative pressure source is in an on state; a top foam disposed on the base foam; a pre-canister defined in the top foam and configured to be disposed in fluid communication with the manifold and the accumulation chamber, the pre-canister disposed in direct fluid communication with the inlet, the pre-canister configured to collect exudate from the wound upon application of negative pressure to the wound, the pre-canister configured to receive pressurized air from the accumulation chamber when the negative pressure source is in an off state, thereby purging the pre-canister by allowing exudate flow from the pre-canister to a final canister; and an intermediate film disposed between the top foam and the base foam, wherein the intermediate film is configured to: allow exudate flow between the manifold and the pre-canister when the negative pressure source is in the on state; allow air flow between the accumulation chamber and the pre-canister when the negative pressure source is in the off state; and allow purging the pre-canister when the negative pressure source is in the off state.

2. The dressing of claim 1, further comprising a first valve configured to fluidly communicate the manifold and the pre-canister, such that: when the negative pressure source is in the on state, the first valve is open, thereby allowing exudate flow from the manifold to the pre-canister; and when the negative pressure source is in the off state, the first valve is closed, thereby preventing exudate flow from the manifold to the pre-canister.

3. The dressing of claim 2, wherein the first valve comprises: a first disc portion defined in the intermediate film and adjacent to an opening in the intermediate film, the opening in fluid communication with the pre-canister, wherein the firstdisc portion is movable between a rest position and a lifted position, wherein the first disc portion prevents fluid communication between the manifold and the opening in the rest position, wherein the first disc portion allows fluid communication between the manifold and the opening in the lifted position; and a first compressible member placed on the opening and the first disc portion, such that the first compressible member is movable between an expanded position and a compressed position, wherein the first compressible member is biased towards the expanded position, wherein the first disc portion is in the rest position when the first compressible member is in the expanded position, wherein the first disc portion is in the lifted position when the first compressible member is in the compressed position; wherein, when the negative pressure source is in the off state, the first compressible member is in the expanded position and the first disc portion is in the rest position, thereby preventing exudate flow from the manifold to the opening and further to the pre-canister; wherein, when the negative pressure source is in the on state, the first disc portion moves from the rest position to the lifted position and the first compressible member moves from the expanded position to the compressed position, thereby allowing exudate flow from the manifold to the opening and further to the pre-canister.

4. The dressing of claim 3, wherein the first compressible member is an open cell foam.

5. The dressing of claim 3, wherein the first compressible member comprises a polyurethane foam.

6. The dressing of claim 3, wherein the first compressible member is bonded to the first disc portion.

7. The dressing of claim 3, wherein the first compressible member is placed in the top foam.

8. The dressing of claim 2, wherein the first valve is defined in the top foam and the intermediate film.

9. The dressing of claim 1, further comprising a second valve configured to fluidly communicate the accumulation chamber and the pre-canister, such that: when the negative pressure source is in the on state, the second valve is closed, thereby preventing air flow from the accumulation chamber to the pre-canister; and when the negative pressure source is in the off state, the second valve is open, thereby allowing air flow from the accumulation chamber to the pre-canister and further purging the pre-canister.

10. The dressing of claim 9, wherein the second valve comprises: a second disc portion defined in the intermediate film and movable between a rest position and a lifted position, wherein the second disc portion prevents fluid communication between the accumulation chamber and the pre-canister in the rest position, wherein the seconddisc portion allows fluid communication between the accumulation chamber and the precanister in the lifted position; and a second compressible member placed on the second disc portion, such that the second compressible member is movable between an expanded position and a compressed position, wherein the second compressible member is biased towards the expanded position, wherein the second disc portion is in the rest position when the second compressible member is in the expanded position, wherein the second disc portion is in the lifted position when the second compressible member is in the compressed position; wherein, when the negative pressure source is in the on state, the second compressible member is in the expanded position and the second disc portion is in the rest position, thereby preventing air flow from the accumulation chamber to the pre-canister; wherein, when the negative pressure source is in the off state, the second disc portion moves from the rest position to the lifted position and the second compressible member moves from the expanded position to the compressed position, thereby opening an air passage to allow air flow from the accumulation chamber to the pre-canister.

11. The dressing of claim 10, wherein the second compressible member is an open cell foam.

12. The dressing of claim 10, wherein the second compressible member comprises a polyurethane foam.

13. The dressing of claim 10, wherein the second compressible member is bonded to the second disc portion.

14. The dressing of claim 10, wherein the second compressible member is placed in the base foam.

15. The dressing of claim 9, wherein the second valve is defined in the base foam and the intermediate film.

16. The dressing of claim 1, further comprising a check valve positioned in the base foam and between the outlet and the accumulation chamber to prevent backflow of air from the accumulation chamber to the outlet.

17. The dressing of claim 16, wherein the check valve is a flapper type valve.

18. The dressing of claim 1, further comprising a third valve configured to fluidly communicate the pre-canister and the final canister, such that: when the negative pressure source is in the on state, the third valve is closed, thereby preventing purging the pre-canister and further preventing exudate flow from the pre-canister to the final canister; and when the negative pressure source is in the off state, the third valve is open, thereby allowing purging the pre-canister and further allowing exudate flow from the pre-canister to the final canister.

19. The dressing of claim 18, wherein the third valve comprises:a third disc portion defined in the intermediate film and movable between a rest position and a lifted position, wherein the third disc portion prevents fluid communication between the pre-canister and the final canister in the rest position, wherein the third disc portion allows fluid communication between the pre-canister and the final canister in the lifted position; and a third compressible member placed on the third disc portion, such that the third compressible member is movable between an expanded position and a compressed position, wherein the third compressible member is biased towards the expanded position, wherein the third disc portion is in the rest position when the third compressible member is in the expanded position, wherein the third disc portion is in the lifted position when the third compressible member is in the compressed position; wherein, when the negative pressure source is in the on state, the third compressible member is in the expanded position and the third disc portion is in the rest position, thereby preventing purging the pre-canister and further preventing exudate flow from the pre-canister to the final canister; wherein, when the negative pressure source is in the off state, the third disc portion moves from the rest position to the lifted position and the third compressible member moves from the expanded position to the compressed position, thereby opening a fluid passage to allow purging the pre-canister and further allow exudate flow from the pre-canister to the final canister.

20. The dressing of claim 19, wherein the third compressible member is an open cell foam.

21. The dressing of claim 19, wherein the third compressible member comprises a polyurethane foam.

22. The dressing of claim 19, wherein the third compressible member is bonded to the third disc portion.

23. The dressing of claim 19, wherein the third compressible member is placed in the base foam.

24. The dressing of claim 18, wherein the third valve is defined in the base foam and the intermediate film.

25. The dressing of claim 1, wherein the final canister is integrated in the dressing.

26. The dressing of claim 1, wherein the final canister is remote from the dressing.

27. The dressing of claim 1, further comprising a top film disposed adjacent to the top foam, such that the top foam is sandwiched between the top film and the intermediate film.

28. The dressing of claim 27, wherein the top film is a drape adapted to provide a fluid seal over the wound.

29. The dressing of claim 27, wherein the top film comprises an adhesive to adhesively bond with the top foam.

30. The dressing of claim 1, further comprising a base film disposed between the manifold and the base foam.

31. The dressing of claim 1, wherein the base film comprises an adhesive to adhesively bond the dressing to the skin.

32. The dressing of claim 1, wherein the negative pressure source is integrated in the dressing.

33. The dressing of claim 32, wherein the negative pressure source is a micro pump.

34. A therapy system for negative pressure wound therapy of a wound on a skin, the therapy system comprising: the dressing of claim 1; and a negative pressure source disposed in fluid communication with the manifold to provide negative pressure to the wound, the negative pressure source comprising an inlet and an outlet, wherein the negative pressure source is configured to generate negative pressure at the inlet and positive pressure at the outlet.

35. The dressing of claim 34, wherein the negative pressure source is a vacuum pump, a suction pump, or a wall suction port.

36. A dressing for negative pressure wound therapy of a wound on a skin, the dressing comprising: a first manifold adapted to be positioned adjacent to the wound for receiving negative pressure, wherein the first manifold is in fluid communication with a negative pressure source to provide negative pressure to the wound, the negative pressure source comprising an inlet and an outlet, the negative pressure source configured to generate negative pressure at the inlet and positive pressure at the outlet; a second manifold disposed on the first manifold for receiving positive pressure from the outlet, wherein the second manifold is in fluid communication with the negative pressure source; and a canister disposed proximal to the second manifold and distal to the first manifold, the canister comprising a bottom surface and a top surface opposite to the bottom surface, wherein the canister is in fluid communication with the second manifold; wherein upon application of negative pressure to the wound: the exudate is drawn from the wound through the first manifold; and the exudate drawn from the first manifold is pushed towards the canister through the second manifold, wherein the exudate is pushed by the positive pressure received by the second manifold.

37. The dressing of claim 36, wherein the top surface of the canister comprises a vent membrane to allow air to escape from the canister as positive pressure flows through the canister.

38. The dressing of claim 36, wherein the bottom surface of the canister comprises one or more canister inlets to allow exudate flow from the second manifold to the canister.

39. The dressing of claim 36, wherein the canister is made up of a transparent material.

40. The dressing of claim 39, wherein the canister comprises volume indicators to assist in measuring or verifying volume of exudate inside the canister.

41. The dressing of claim 36, wherein the canister is made up of flexible plastic sheets which are sealed around their periphery.

42. The dressing of claim 41, wherein the flexible plastic sheets comprise polyvinyl chloride, polyurethane, or similar flexible plastic sheet material.

43. The dressing of claim 36, further comprising a releasable adhesive layer to adhesively bond the canister to the second manifold.

44. The dressing of claim 36, wherein the canister is adhesively bonded to the second manifold.

45. The dressing of claim 36, wherein the canister contains a super absorbent material to contain the exudate.

46. The dressing of claim 36, further comprising a base layer to adhesively bond the dressing to the skin.

47. The dressing of claim 36, wherein the negative pressure source is a vacuum pump, a suction pump, or a wall suction port.

48. The dressing of claim 36, wherein the negative pressure source is a micro pump or a peristaltic pump.

49. The dressing of claim 36, wherein the negative pressure source is integrated in the dressing.

50. The dressing of claim 49, further comprising a mounting pad for mounting the negative pressure source on the dressing.

51. The dressing of claim 49, wherein the negative pressure source comprises a reservoir for receiving the exudate from the first manifold and supplying the same exudate to the second manifold.

52. The dressing of claim 36, wherein the negative pressure source is remote from the dressing.

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