Negative pressure wound therapy (NPWT) dressing

Abstract

The present disclosure generally relates to a negative pressure wound therapy (NPWT) dressing (100) comprising a backing layer (101) and an adhesive skin contact layer (102); the adhesive skin contact layer (102) is configured to releasably adhere the dressing (100) to a skin surface, the backing layer (101) comprising a coupling member (104); and the coupling member (104) comprising tubing (105) configured to connect the dressing (100) to a negative pressure source and a remote fluid collection means.

Description

Technical Field

[0001] The present disclosure generally relates to negative pressure wound therapy (NPWT) dressings. The present invention similarly relates to systems and kits comprising such dressings.

Background Art

[0002] Negative pressure wound therapy (NPWT) is a technique for promoting the healing of, for example, surgical, acute and chronic wounds by applying a sub-atmospheric pressure to the wound using a negative pressure pump. The healing of the wound is achieved by applying a negative pressure such as a vacuum through a dressing or cover applied over the wound. This draws out excess wound exudate, thus increasing blood flow to the area and promoting the formation of granulation tissue. The NPWT technique also enables the reduction of external disturbances to the wound and transports excess fluid away from the wound site.

[0003] To date, the NPWT technique has mainly been applied to patients while they are in a hospital environment. However, recent product developments have enabled patients to use this technique in a home environment.

[0004] In a hospital environment, the wound to be treated is generally an open cavity wound that is first filled with a wound filler such as gauze or foam. The wound is then sealed with an adhesive film and can be connected to a vacuum pump via a drain or port. The size of the foam, gauze and / or adhesive film can be adapted and cut according to the size, shape or type of the wound. The application procedure is generally carried out by a caregiver. The negative pressure pumps used in such systems are generally large and generally have a large capacity for treating large amounts of wound exudate. Such systems generally include fluid collection means such as a canister located remotely from the dressing. The wound exudate discharged from the wound is transferred by tubing to the canister for fluid collection.

[0005] Within a home environment, a portable NPWT device that a patient can carry around is generally preferred. Portable NPWT devices generally include an absorbent dressing configured to be connected to a negative pressure source using tubing. The pumps used in such devices are generally relatively small and have a more limited capacity.

[0006] In most portable NPWT systems, the dressing serves as the only means of collecting wound exudate. When dealing with large amounts of wound exudate, the dressing can become rapidly saturated. This can negatively affect the dressing's ability to remain on the skin; that is, the wearing time of the dressing is shortened. Generally, the dressing needs to be discarded and replaced with a new one.

[0007] For negative pressure wound therapy to operate properly and in a controlled manner, the NPWT system needs to be stable. This is particularly true in NPWT systems that include remotely located fluid collection means such as a canister. In such systems, exudate is continuously or intermittently transferred through the tubing or conduit connecting the dressing to the canister. Therefore, the negative pressure source, i.e., the vacuum pump, needs to be operated at regular intervals. For example, if the negative pressure level transmitted to the wound is not within the desired threshold, the pump needs to be operated to ensure that the correct negative pressure is transmitted. An example of a situation where the pump is required to function more powerfully is when there is an unwanted air leak within the system. An overly high operating frequency of the negative pressure source; i.e., the pump, will be associated with unwanted noise and battery consumption.

[0008] In summary, there is a need to provide improvements regarding the provision of stable and controlled negative pressure wound therapy. Specifically, there is a need to provide dressings for portable NPWT systems and devices that enable efficient removal of exudate while improving the overall control and stability of the NPWT system.

Prior Art Documents

Patent Documents

[0009] [Patent Document 1] European Patent Application Publication No. 2759310 [Patent Document 2] European Patent Application Publication No. 3023083 [Summary of the Invention] [Problems to be Solved by the Invention]

[0010] In view of the above problems, an object of the present disclosure is to provide improvements in the capabilities of a dressing material for negative pressure wound therapy (NPWT), and more particularly to provide a portable NPWT system that improves treatment stability and is highly reliable. [Means for Solving the Problems]

[0011] According to a first aspect of the present disclosure, in a negative pressure wound therapy (NPWT) dressing material including a backing layer, an adhesive skin contact layer, and an absorbent structure disposed between the backing layer and the adhesive skin contact layer; the adhesive skin contact layer is configured to adhesively attach the dressing material to the skin surface in a detachable manner, and the backing layer includes a coupling member including tubes configured to connect the dressing material to a negative pressure source and a remote fluid collection means, the negative pressure wound therapy (NPWT) dressing material, wherein the backing layer has a water vapor transmission rate (MVTR) in the range of 500 to 3500 g / m 2 / 24 h as measured by NWSP070.4R0 is provided.

[0012] The present disclosure is based on the recognition that the water vapor transmission rate of the backing layer, i.e., the rate at which the backing layer (and thus the dressing material as well) can evaporate moisture, has an effect on the stability of negative pressure wound therapy and the overall NPWT system.

[0013] It is generally known that absorbent dressings with a backing layer having a very high water vapor transmission rate (MVTR) are required for exudative wounds. In contrast to what is known in the art, the inventors have recognized that in fact, a backing layer having a low MVTR actually has an accompanying positive effect when such a dressing is applied in negative pressure wound therapy.

[0014] More specifically, the inventors have recognized that a backing layer having an MVTR in the range of 500 to 3500 g / m 2 / 24 h improves negative pressure wound therapy and system stability, has a positive effect on the negative pressure source, i.e., the pump, and the negative pressure source does not need to function as strongly during treatment. This range can still ensure that excess moisture is efficiently removed from the dressing to promote wound healing.

[0015] The NPWT dressing of the present disclosure is configured to be connected to a negative pressure source, i.e., a pump, and to fluid collection means that are located remotely from the dressing, i.e., located at a location between the dressing and the negative pressure source or integrated within the same unit as the negative pressure source. In other words, wound exudate will be transferred from the dressing through tubing to a separate fluid collection means such as a canister.

[0016] The inventors have found that a backing layer having an MVTR from 500 to 3500 g / m 2 / 24 h, preferably 600 to 2700 g / m 2 / 24 hours also provides a stable wound therapy with fewer demands on the pump and the overall system, and ensures an optimal balance between establishing an environment favorable for wound healing, i.e., ensuring that excess moisture evaporates from the dressing to prevent maceration.

[0017] In an embodiment, the tubing of the dressing includes a fluid conduit configured to remove fluid from the dressing and an air conduit configured to supply air to the fluid conduit and / or the dressing.

[0018] A small and controlled influx of air can be beneficial in more efficiently withdrawing fluid from the wound site and transporting the fluid to remotely located fluid collection means, such as a canister. The introduction of air helps to dissipate potential occlusions or liquid columns formed within the tubing.

[0019] In an embodiment, the backing layer has a tensile strength in the machine direction (MD) and / or the machine cross direction (CD) of 30 to 70 MPa, preferably 35 to 55 MPa, as measured by ISO 527-3 / 2 / 2.

[0020] The inventors have also discovered that the tensile strength of the backing layer similarly affects providing a stable and highly reliable treatment. The backing layer must have sufficient rigidity to prevent tearing or breaking of the backing layer during patient movement. For example, as the absorbent structure becomes thicker, there is a greater likelihood of rubbing against the backing layer at the edges, and thus the edges of the absorbent structure are particularly prone to breaking. If perforations or slits are formed in the backing layer, this can be accompanied by an undesirable air leak into the dressing and the system. As a result, the stability of the treatment and the system is compromised. However, the backing layer must still have sufficient flexibility to allow the dressing to adapt to the movement of the user or the flexion of a joint such as the knee.

[0021] In an embodiment, the backing layer comprises a thermoplastic elastomer, preferably a thermoplastic polyurethane.

[0022] Such layers are associated with flexibility and flexibility.

[0023] As mentioned above, the NPWT dressing of the present disclosure includes an absorbent structure disposed between a backing layer and an adhesive skin contact layer. Generally, the backing layer and the adhesive skin contact layer are configured to extend beyond the periphery of the absorbent structure to form an edge portion along the contour of the absorbent structure.

[0024] In a preferred embodiment, the adhesive skin contact layer includes a plurality of apertures in a region below the absorbent structure, but is lacking in apertures in the region forming the edge portion.

[0025] The apertures serve to improve the absorption of wound exudate into the covering material and are thus disposed in the region where absorption occurs. The region of the absorbent layer forming the edge portion of the covering material preferably lacks apertures. In this way, the adhesion to the skin is enhanced and the residual capacity of the covering material is thereby extended.

[0026] The absorbent structure is preferably configured not only to optimize the distribution of wound exudate within the covering material but also to ensure the removal of exudate towards remotely located fluid collection means. The inventors have discovered that the absorbent structure can be designed to achieve an appropriate liquid distribution balance between the covering material, which serves as a liquid "compartment" for holding and storing both liquids, and the remotely located fluid collection means.

[0027] In an embodiment, the absorbent structure contains superabsorbent particles in an amount of 10 - 20 mg / cm 2 , preferably 13 - 17 mg / cm 2 within the absorbent structure.

[0028] The inventors have discovered that this range is beneficial for the covering materials according to the present disclosure. Such an absorbent structure absorbs exudate at a "reasonable" level. If too much SAP is included, the SAP layer may swell and absorb too much and too rapidly. This can have the effect that the covering material assumes the role of the sole or at least dominant means for fluid collection. In the context of the present disclosure, the balance between the remotely located fluid collection means, such as a canister, and the covering material (which is likewise considered a fluid collection means) is preferably 50:50, for example at least 40:60 or 60:40. This liquid distribution balance is important for improving the wearing time of the covering material.

[0029] In an embodiment, the absorbent structure includes a first liquid spreading layer, a superabsorbent layer, and a second liquid spreading layer, and the superabsorbent layer is disposed between the first and second liquid spreading layers.

[0030] The first liquid spreading layer is configured to absorb and distribute liquid flowing from the wound site. The liquid spreading layer can distribute and spread the wound exudate evenly over a large surface area so that it can be absorbed by the superabsorbent layer. The second liquid spreading layer distributes the exudate evenly and allows a larger surface area for the exudate to evaporate from the backing layer.

[0031] In an embodiment, the absorbent structure is embossed.

[0032] The embossed absorbent structure improves the fluid handling properties of the covering material and contributes to a balanced and more controlled spread of wound exudate within the covering material. Further, the embossed absorbent structure allows the covering material to maintain its shape and thinness while also having flexibility. The enhanced spread and distribution of the exudate are obtained within the compressed regions of the structure.

[0033] In an embodiment, at least a portion of the backing layer and the absorbent structure includes openings that are disposed under the bonding members.

[0034] This is for ensuring fluid communication between the wound site and the tubing of the covering material, and thus also between the wound site and the fluid collection means disposed remotely.

[0035] In an embodiment, the covering material further includes a liquid spreading layer disposed between the backing layer and the absorbent structure, and the liquid spreading layer is configured to extend over at least 90% of the surface area of the absorbent structure and is lacking in openings.

[0036] The liquid spreading layer is a continuous layer that extends substantially across the entire absorbent structure. The liquid spreading layer serves several functions within the dressing of the present disclosure. First, this liquid spreading layer improves the spreading and distribution of wound exudate within the dressing, forming a larger surface area through which the exudate can evaporate from the dressing (through the backing layer). Thus, the larger surface area of the liquid spreading layer can "compensate" for the low moisture vapor transmission rate (MVTR) of the backing layer.

[0037] Furthermore, the liquid spreading layer is thought to contribute to a controlled and balanced liquid distribution between the dressing and remote fluid collection means. The ability of the dressing to function as a fluid collection means is optimized while still allowing for the removal and transport of a substantial portion of the exudate from the dressing using tubing.

[0038] Another advantage is that the liquid spreading layer improves the distribution of potential "backflow" exudate, i.e., exudate flowing in the opposite direction (from the tubing to the dressing). This can occur, for example, when the dressing is separated from the negative pressure source and / or remote fluid collection means.

[0039] The dressing can further include a permeable layer disposed between the adhesive skin contact layer and the absorbent structure, and the permeable layer includes a spacer fabric.

[0040] The permeable layer helps to facilitate the transmission of negative pressure from the negative pressure source to the wound site.

[0041] According to a second aspect, - the negative pressure wound therapy (NPWT) dressing described above, - a negative pressure source, - a remote fluid collection means fluidly connected to the negative pressure source and the dressing, A negative pressure wound therapy (NPWT) system is provided that includes.

[0042] In an embodiment, the remote fluid collection means is a canister, and the canister and the negative pressure source are arranged inside the same device; the device includes a housing, the negative pressure source is arranged inside this housing, and the canister is detachably connected to the housing.

[0043] The detachable configuration enables a user or caregiver to remove the canister, empty the collected liquid, and then reattach the canister to the housing.

[0044] In an embodiment, the NPWT system includes means for supplying air to the dressing at a flow rate of 2 to 7 ml / min during operation.

[0045] A small and controlled air inflow can be beneficial for more efficiently withdrawing fluid from the wound site and transporting the fluid to a remotely located fluid collection means such as a canister. The introduction of air helps to dissipate potential exudate blockages or liquid columns formed within the tubing.

[0046] In other words, air is supplied to the dressing using an air conduit at a relatively low and controlled rate such that it can solve problems associated with liquid columns and blockages in the tubing. In this way, air also helps to transmit the desired pressure level to the wound. If too much air is introduced, this can have a negative impact on the stability of the system, and generally, the pump operates more frequently.

[0047] According to a third aspect, there is provided a kit including a negative pressure wound therapy (NPWT) dressing as described above.

[0048] Further features of the present disclosure and the attendant advantages will become apparent upon examination of the appended claims and the following description. Those skilled in the art will recognize that, without departing from the scope of the present disclosure, different features of the present disclosure can be combined to create embodiments other than those described below.

[0049] Various aspects of the present disclosure will be readily understood from the following detailed description and the accompanying drawings, including its particular features and advantages.

Brief Description of the Drawings

[0050]

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Figure 2b

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DETAILED DESCRIPTION OF THE INVENTION

[0051] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which presently preferred embodiments of the disclosure are shown. However, the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided for completeness and to fully convey the scope of the disclosure to those skilled in the art. Throughout, the same reference numerals mean the same elements.

[0052] FIGS. 1 and 2a show a negative pressure wound therapy (NPWT) covering material 100 according to an exemplary embodiment of the present disclosure. The NPWT covering material 100 includes a backing layer 101, an adhesive skin contact layer (see 102 in the figure), and an absorbent structure 103 disposed between the backing layer 101 and the adhesive skin contact layer; the adhesive skin contact layer is configured to adhere the covering material 100 to the skin surface, and the backing layer 101 includes a coupling member 104 that includes tubes 105 configured to connect the covering material 100 to a negative pressure source and a remote fluid collection means, and the backing layer 101 has a water vapor transmission rate (MVTR) in the range of 500 to 3500 g / m 2 / 24 h as measured by NWSP070.4R0(15).

[0053] As used herein, the term "negative pressure wound therapy covering material" means a covering material for use in negative pressure wound therapy. In the context of the present disclosure, "negative pressure wound therapy" means a treatment that utilizes a negative pressure source (e.g., a vacuum pump) to remove excess fluid from a wound. The wound can be an open wound or a closed wound, i.e., a surgical incision, and thus the term also encompasses the field of use of the term "topical negative pressure (TNP) therapy," which is often used in connection with surgical incisions.

[0054] The NPWT dressing 100 of the present disclosure includes an absorbent structure that can also be referred to as a "wound pad". The NPWT dressing is generally referred to as an "edged dressing". The backing layer 101 and the adhesive skin contact layer are arranged to extend beyond the contour of the absorbent structure 103 to form an edge portion 108.

[0055] As used herein, the term "skin surface" means the skin of the wearer. The skin may include wounds to be treated such as open wounds or closed wounds.

[0056] "Moisture vapor transmission rate (MVTR)" is the rate at which the backing layer allows moisture to penetrate from the backing layer. The moisture vapor transmission rate is measured by the standard method NWSP070.4R0(15). The MVTR is measured at a temperature of 38°C.

[0057] The moisture vapor transmission rate (MVTR) of the backing layer 101, when measured by NWSP070.4R0(15), is in the range of 500 - 3500 g / m 2 / 24h, preferably 600 - 2700, for example 1400 - 2600 g / m 2 / 24h.

[0058] Surprisingly, this range has been shown to produce a positive effect when the dressing is used in wound treatment. A more stable treatment is observed with a relatively low frequency of operation of the negative pressure source, and yet the exudate fluid collected inside the dressing can be successfully evaporated from the backing layer to the surrounding environment. Overall, this results in a positive effect from the perspective of battery consumption, noise reduction, and long - term and more stable wound treatment.

[0059] The NPWT dressing 100 of the present disclosure is adapted for use in an NPWT system that includes remotely located fluid collection means. As used herein, the term "remotely located fluid collection means" means that the fluid collection means is located at a certain distance from the dressing, such as, for example, between the dressing and the negative pressure source, or is connected to the negative pressure source. The negative pressure source and the fluid collection means may also be disposed within the same NPWT device.

[0060] When the dressing 100 of the present disclosure is utilized within an NPWT system that includes remotely located fluid collection means, wound exudate is withdrawn from the wound site to the fluid collection means using tubing 105.

[0061] For continuous (or intermittent) removal of exudate through the tubing, it is required to operate the NPWT source, i.e., the vacuum pump, at regular intervals. However, if the pump is operated too frequently and at a rate "more than necessary", this will result in negative consequences such as noise and battery depletion. In the dressing 100 of the present disclosure, as demonstrated in Example 1 below, at least a 26% reduction in pump operation was observed.

[0062] The tubing 105 can include a fluid conduit 106 configured to remove fluid from the dressing and an air conduit 107 configured to supply air to the fluid conduit 106 and / or the dressing 100. Further, the tubing 105 is configured to transmit negative pressure to the dressing and the wound site.

[0063] The tubing 105 and / or the coupling member 104 can be any suitable flexible tubing made of an elastomeric and / or polymeric material. The tubing is attached to the coupling member 104. In an embodiment, the tubing 105 is rigidly attached to the coupling member 104. In an alternative embodiment, the tubing 105 is detachably attached to the coupling member 104.

[0064] The bonding member 104 generally includes an attachment portion configured to be attached to the backing layer of the covering material. The bonding member may be attached to the backing layer by adhesion. The bonding member may similarly include a fluid inlet and a fluid outlet configured to be connected to the tubular members 105, namely the air conduit 107 and the fluid conduit 106, respectively.

[0065] The bonding member may have a structure as defined in Patent Document 1 (EP Application No. 13152841.6).

[0066] In an embodiment, the distal end of the tubular member 105 is connected to a first connector portion 109. The first connector portion 109 is configured to be connected to a remote fluid collection means, such as a second connector portion coupled to a canister, and in the embodiment, to be connected to a negative pressure source (see, for example, FIG. 4 in which a second connector portion 123 coupled to a canister is illustrated).

[0067] In an embodiment, the backing layer 101 has a tensile strength in the machine direction (MD) and / or the machine cross direction (CD) of 30 to 70 MPa, preferably 35 to 55 MPa, when measured according to ISO 527-3 / 2 / 200. The tensile strength is measured with a 15 mm wide strip.

[0068] Therefore, the backing layer 101 has sufficient "strength" to withstand the forces applied to the backing layer when the patient moves and to allow for flexibility and sufficient stretchability.

[0069] The backing layer 101 generally includes a thermoplastic elastomer. The thermoplastic elastomer has the ability to stretch and contract up to a moderate elongation and return to its original shape upon removal of the stress. Examples of suitable materials including thermoplastic elastomers include polyurethane, polyamide, and polyethylene.

[0070] The backing layer may similarly be a laminate of a polyester nonwoven material and at least one polyurethane film.

[0071] Preferably, the backing layer contains thermoplastic polyurethane.

[0072] The thickness of the backing layer may be in the range of 10 to 40 μm, preferably 15 to 30 μm.

[0073] The backing layer 101 can include at least one film. For example, the backing layer can include two or more films. In an embodiment, the backing layer is a laminate formed by two or more films. A thin layer of an adhesive such as a polyacrylate adhesive can be applied to the backing layer to attach the backing layer to the adhesive skin contact layer and / or any other layer of the absorbent structure or covering material. Within the framework of the present disclosure, the backing layer 101 includes at least one film containing a thermoplastic elastomer and an adhesive (such as polyacrylate) applied thereon. The adhesive can be applied in a continuous or discontinuous pattern.

[0074] Figures 2a and 2b show an exemplary covering material of the present disclosure including multiple layers.

[0075] The backing layer 101 is the outermost layer of the covering material and is configured to face outward as seen from the skin of the wearer.

[0076] The absorbent structure 103 is disposed between the backing layer 101 and the adhesive skin contact layer 102. The backing layer 101 and the adhesive skin contact layer 102 are configured to extend beyond the periphery of the absorbent structure 103 to form an edge portion 108 along the contour of the absorbent structure 103. In other words, the covering material includes a pad portion and an edge portion 108. The pad portion includes the absorbent structure 103 and, in an embodiment, an additional covering material layer.

[0077] In a preferred embodiment, the adhesive skin contact layer 102 includes a plurality of apertures 110 within a region below the absorbent structure 103, but no apertures are provided within the region forming the edge portion 108.

[0078] The fact that no aperture is provided within the edge portion of the covering material is beneficial for improving the adhesion at the edge portion 108 of the covering material and thus improving the residual ability of the covering material.

[0079] The adhesive skin contact layer 102 is the lowermost layer of the covering material. The adhesive skin contact layer 102 is configured to adhesively attach the covering material to the skin surface in a removable manner. In other words, the adhesive skin contact layer 102 is configured to contact the skin or wound of the wearer. This layer can also be referred to as the "wound contact layer" or "skin contact layer".

[0080] The adhesive skin contact layer 102 preferably contains a silicone-based adhesive, i.e., a silicone gel. The adhesive skin contact layer containing the silicone gel is gentle to the skin and can be easily removed without causing trauma. This adhesive skin contact layer has sufficient adhesive force to the skin in such a form that the covering material stays in place, and is configured to maintain its adhesive force even when removal and reattachment are repeated.

[0081] As shown in FIG. 2a, the adhesive skin contact layer 102 can include two layers. For example, the adhesive skin contact layer 102 can include a polymer-based film 102a and a silicone gel layer 102b, and the silicone gel layer 102b is configured to contact the skin of the wearer.

[0082] The polymer-based film 102a is preferably a breathable film and can include, for example, polyethylene, polyamide, polyester, or polyurethane. Preferably, the polymer-based film contains polyurethane. The thickness of the polyurethane film can be 15 - 100 μm, for example 20 - 80 μm, preferably 20 - 60 μm.

[0083] Examples of silicone gels suitable for use within the adherent skin contact layer 102 and / or within the silicone gel layer 102b include the two-component RTV systems described herein, such as Q72218 (Dow Corning) and SilGel612 (Wacker Chemie AG), as well as NuSil silicone elastomers. In embodiments of the present invention, the adhesive can include a soft silicone gel having a softness (penetration) of 8 to 22 mm, such as 12 to 17 mm, as measured by methods based on ASTM D 937 and DIN 51580, the relevant methods being described in Patent Document 2 (European Patent Application No. 14194054.4). The thickness of the adherent skin contact layer is generally at least 20 μm. The thickness of the adherent skin contact layer can be 100 to 200 μm.

[0084] The aperture 110 of the adherent skin contact layer 102 is configured to extend through the polymer film 102a (if present) and the silicone gel layer 102b.

[0085] In embodiments, the absorbent dressing has a holding capacity of 300 to 700 mg / cm 2 , preferably 400 to 600 mg / cm 2 when measured by the test method described in Example 3.

[0086] The inventors have discovered that the holding capacity of the dressing is important to ensure that a balanced liquid distribution is achieved between the two fluid collection means (the dressing and, for example, a canister). This improves the wearing time of the dressing. If the dressing absorbs wound exudate too quickly and "too much", less exudate will be transferred to the remote fluid collection means. In this situation, the dressing serves as the dominant fluid collection means, and as a result, the time the dressing can be worn may be reduced, and the dressing may need to be changed more frequently. In contrast, if too much exudate is transferred to a remote fluid collection means, such as a canister, the canister may need to be emptied and replaced overly frequently.

[0087] The dressing of the present disclosure is configured to store 35 to 65%, for example 40 to 60%, of the wound exudate and remove 35 to 65%, for example 40 to 60%, of the wound exudate from the dressing to a fluid collection means remote from the dressing.

[0088] The distribution of the liquid between the dressing and the cannister is preferably 40:60 to 60:40. The inventors have found that such a distribution can be maintained for up to 9 days of treatment without the need to replace the dressing (see Example 2).

[0089] The absorbent structure 103 is configured to absorb the wound exudate and efficiently distribute such wound exudate. Thus, the absorbent structure 103 functions as a temporary reservoir for holding and distributing the exudate while also controlling the liquid transport to the cannister using the tubing 105.

[0090] The absorbent structure 103 may include one or more layers, where at least one of these layers is a superabsorbent layer 103a containing a superabsorbent polymer (SAP).

[0091] A "superabsorbent polymer", i.e., "SAP", is a polymer that can absorb up to 300 times its own weight in an aqueous fluid. Superabsorbent polymers are composed of water-swellable and water-insoluble polymers that have the ability to absorb large amounts of fluid upon the formation of a hydrogel. Superabsorbent polymers for use in accordance with the present disclosure can be inorganic or organic crosslinked hydrophilic polymers such as polyvinyl alcohol, polyethylene oxide, crosslinked polyacrylate, etc. Generally, superabsorbent polymers (SAP) contain sodium acrylate. The SAP material is in the form of particles, fibers, flakes or the like. Preferably, the SAP material is in the form of superabsorbent polymer (SAP) particles. The size of the superabsorbent particles can be in the range of 45 to 850 μm, preferably 150 to 600 μm.

[0092] In an embodiment, the absorbent structure is 10 - 20 mg / cm2 Preferably, it contains superabsorbent particles in an amount of 13 to 17 mg / cm 2 .

[0093] The inventors have discovered that this range is beneficial for the coating material according to the present disclosure. Such an absorbent structure absorbs exudate at a "reasonable" level. If too much SAP is included, the SAP layer may swell and absorb too much and too quickly. This can result in the coating material serving as the sole or at least dominant fluid collection means. In the context of the present disclosure, the balance between a remotely located fluid collection means, such as a canister, and the coating material (which is also considered a fluid collection means) is preferably 50:50, for example at least 40:60 or 60:40. As mentioned above, this balance is important for improving the wearing time of the coating material.

[0094] The absorbent structure 103 preferably has a basis weight of 250 to 550 g / m 2 , preferably 350 to 450 g / m 2 . In this way, liquid distribution is controlled and an appropriate balance between liquid absorption and liquid removal from the coating material is observed. Furthermore, the coating material is flexible and can better adapt to the movements of the wearer.

[0095] The absorbent structure 103 can include one or more layers, where at least one layer is a superabsorbent layer.

[0096] Preferably, the absorbent structure includes at least one superabsorbent layer 103a and at least one liquid spreading layer.

[0097] As shown in FIG. 2b, the absorbent structure 103 includes three layers 103a - c.

[0098] The lowermost layer 103b of the absorbent structure 103 is a liquid spreading layer 103b. Exudate entering the liquid spreading layer 103b from the wound site is evenly distributed before entering the other layers of the absorbent structure 103, thus creating a larger surface area towards the superabsorbent layer 103a and the other layers of the absorbent structure 103 and / or the covering material 100.

[0099] The absorbent structure 103 includes a first liquid spreading layer 103b, a superabsorbent layer 103a, and a second liquid spreading layer 103c, and the superabsorbent layer 103a is disposed between the first and second liquid spreading layers 103b, 103c.

[0100] The first and / or second liquid spreading layer can include any material having the ability to efficiently distribute exudate. For example, the first and / or second liquid spreading layer includes a nonwoven material.

[0101] In an embodiment, the first liquid spreading layer 103b is disposed below the superabsorbent layer 103a and has a greater liquid spreading ability than the second liquid spreading layer 103c. Thus, an absorbent structure with a liquid spreading gradient is achieved, which affects the ability of the absorbent structure 103 to hold and remove liquid from and within the covering material.

[0102] For example, the first liquid spreading layer 103b can include a nonwoven fabric. The nonwoven fabric can have a grammage in the range of 20 - 50 g / m 2 (gsm), for example 30 - 40 g / m 2 (gsm). The thickness of the liquid spreading layer 103b can be 0.2 - 1.2 mm, for example 0.2 - 0.6 mm. The thickness is measured under dry conditions.

[0103] The second liquid spreading layer 103c can be a thin fabric or nonwoven layer. Generally, the spreading ability of the upper layer 103c is lower than that of the lower liquid spreading layer 103b.

[0104] Layer 103c also helps prevent leakage of SAP particles from the superabsorbent layer 103a. The SAP particles in the superabsorbent layer 103a chemically bond with the exudate entering the superabsorbent layer 103a, thereby forming an aqueous gel. Layer 103c prevents the gelled particles from moving towards the backing layer 101 and towards the bonding member 104 including the tubing 105. Thus, unwanted blockage by the gel particles inside the tubing 105 is prevented. Preferably, layer 103c is a liquid spreading layer and helps create a larger indirect surface of the distributed liquid towards the backing layer 101 of the covering material 100. Layer 103c or 103b also serves as a "support layer" and serves as a carrier during the manufacturing process.

[0105] The various layers of the absorbent structure create a composite liquid absorption and retention structure, and improved liquid distribution is observed. Specifically, a controlled distribution of the exudate being retained and removed respectively was observed.

[0106] The absorbent structure 103 is preferably embossed. In other words, the surface of the absorbent structure 103 is structured and may include a plurality of depressions and protrusions (not shown). This is beneficial because the absorbent structure 103 including multiple layers can become stiff and thick with an increase in basis weight. The embossing allows the absorbent structure to be flexible while maintaining its shape and thickness. The embossed absorbent structure also ensures a controlled spread of the wound exudate inside the covering material 100. Enhanced spread and distribution of the exudate are obtained within the compressed regions of the structure.

[0107] The superabsorbent layer 103a can be an airlaid superabsorbent layer. In an embodiment, the airlaid superabsorbent layer 103a includes superabsorbent particles, cellulosic fibers, and bicomponent fibers.

[0108] For example, the airlaid superabsorbent layer can include the following: - 30 to 50 wt%, preferably 35 to 50 wt% of superabsorbent particles, - 30 to 50% by weight, preferably 40 to 50% by weight of cellulosic fibers, - 3 to 10% by weight, preferably 5 to 8% by weight of bicomponent fibers, - 3 to 8% by weight of polyethylene.

[0109] Such a superabsorbent layer enables improved liquid handling characteristics and proper liquid distribution. Furthermore, it prevents gel blockage and prevents the absorbent structure from collapsing when dealing with large amounts of fluid.

[0110] The bicomponent fibers act as a binder and in particular maintain the shape of the SAP layer in the wet state. The bicomponent fibers may be made of polyethylene and polyethylene terephthalate (PE / PET).

[0111] The thickness of the superabsorbent layer 103a can be 0.8 to 2.5 mm, for example 1.4 to 2.2 mm, for example 1.8 to 2.0 mm. The thickness is measured under dry conditions.

[0112] In an embodiment, the absorbent structure 103 includes an additional layer.

[0113] As shown in FIGS. 2a and 2b, the backing layer 101 and at least a portion of the absorbent structure 103, if present, include an opening 111 disposed under the bonding member 104. In FIG. 2b, the absorbent structure 103 includes three layers each including one opening. However, it is equally conceivable to have one opening in only one layer or two layers of the absorbent structure 103.

[0114] The opening ensures fluid communication between the wound site and the fluid collection means disposed remotely therefrom. It also enables the transmission of negative pressure to the wound site.

[0115] The bonding member 104 is on top of the opening 111 in the backing layer (as best shown in FIG. 2b).

[0116] The covering material 100 can further include a liquid spreading layer 112 disposed between the backing layer 101 and the absorbent structure 103, where the liquid spreading layer 112 is configured to extend across at least 90% of the surface area of the absorbent structure 103 and no openings are formed. When the absorbent structure 103 includes two liquid spreading layers (103b, 103c), the liquid spreading layer 112 on the absorbent structure can be referred to as a third liquid spreading layer.

[0117] Preferably, the liquid spreading layer 112 is configured to extend across the entire surface area of the absorbent structure 103. Thus, the liquid spreading layer 112 and the absorbent structure 103 have the same outer dimensions and cross-sectional area. No openings are formed in the liquid spreading layer 112.

[0118] The liquid spreading layer 112 is configured to improve the spreading of wound exudate and create a larger surface area through which moisture can evaporate through the backing layer 101.

[0119] The liquid spreading layer 112 is preferably hydrophilic and porous. In this way, the exudate can be efficiently transferred from the wound site through the liquid spreading layer 112 to the tubing 105. Since the liquid spreading layer 112 does not contain any openings, it prevents gelling particles and relatively large unwanted microparticles from entering the tubing 105 of the covering material 100.

[0120] The liquid spreading layer 112 can be a fibrous material such as a nonwoven fabric, and thus can impart appropriately balanced rigidity to the layer and the covering material as the layer and the covering material. The nonwoven liquid spreading layer 112 has the ability to distribute fluid over most of the material and transfer exudate in a controlled manner to the tubing 105 that connects the remotely located fluid collection means and the covering material.

[0121] The liquid spreading layer 112 helps move fluid away from the wound site and away from the absorbent structure 103, while ensuring that the maximum absorption capacity of the absorbent covering material is utilized.

[0122] The liquid spreading layer 112 is similarly beneficial for spreading potential exudate flowing from the fluid conduit 106 towards the dressing, i.e., exudate flowing in the "wrong" direction. Backflow of exudate can occur when the person wearing the dressing disconnects the dressing from the negative pressure source and the fluid collection means. For example, a patient may disconnect an NPWT dressing when taking a shower or changing clothes. The liquid spreading layer 112 ensures that such backflow of exudate is spread rather than flowing back towards the wound site at a single point. In this way, the wound site can be kept relatively dry.

[0123] The liquid spreading layer 112 may include a meltblown, spunbonded or spunlace nonwoven fabric. Examples of suitable polymers for use within the nonwoven liquid spreading layer 112 include polyethylene, polyester, polypropylene and other polyolefin homopolymers and copolymers. For example, a nonwoven web containing thermoplastic fibers of polypropylene and polyethylene fibers or mixtures thereof may be used. The web may have a high thermoplastic fiber content and may contain at least 50%, for example at least 70%, thermoplastic fibers. The nonwoven fabric may be, for example, a mixture of polyester and viscose in a ratio of 70:30. The basis weight of the nonwoven fabric may be in the range of 10 - 80 g / m 2 , for example 20 - 50 g / m 2 . The liquid spreading layer may similarly be a spunbond - meltblown or spunbond - meltblown - spunbond (SMS) web.

[0124] The dressing 100 may further include a permeable layer 113 disposed between the adhesive skin - contact layer 102 and the absorbent structure 103. The permeable layer 113 may include a foam, a needle - punched nonwoven fabric, a through - air - bonded nonwoven fabric or a spacer fabric. The permeable layer 113 is not limited to a particular material and any material configured to reliably transmit negative pressure to the wound area in both wet and dry states can be used. The permeable layer 113 ensures that fluid can be transported into the absorbent structure away from the wound site so that the skin can remain relatively dry.

[0125] Preferably, the permeable layer 113 includes a spacer fabric. The spacer fabric is a three-dimensional material often used in negative pressure wound therapy (NPWT) dressings.

[0126] In an embodiment, the spacer fabric layer has a thickness of 1.5 to 4 mm, for example 2 to 3 mm. The thickness is measured under dry conditions. The basis weight of the spacer fabric is 150 to 500 g / m 2 (gsm), for example 200 to 350 g / m 2 (gsm), and can be.

[0127] The spacer fabric layer 113 generally includes a top layer, a bottom layer, and an interconnecting layer of pile filaments between the top and bottom layers. The interconnecting layer of pile filaments can have a fineness of 200 to 500 denier, for example 250 to 350 denier.

[0128] The spacer fabric layer 113 has high compressive strength and is configured to withstand the pressure applied to the dressing during use. After the compressive force is applied to the dressing, the permeable layer 113 is configured to return to its original shape immediately after the force is removed.

[0129] In an embodiment, the dressing includes a plurality of adhesive stripes 114 between the permeable layer 113 and the absorbent structure 103.

[0130] The adhesive stripes 114 are configured to stop the flow of exudate towards the coupling member 104 and the tubing 105. As described above, the dressing 100 of the present disclosure preferably has a structure that allows for a proper and substantially equal balance between remotely located fluid collection means and the dressing. Preferably, about 40 to 60% of the wound exudate is addressed by the dressing, while 40 to 60% is transported to the canister.

[0131] When wound exudate is flowing from the wound site, it is first addressed by the permeable layer 113. When it exits the permeable layer 113, the adhesive stripe 114 serves to direct the exudate into the absorbent structure 103 above rather than flowing directly towards the tubing 105. Thus, having the adhesive stripe 114 can contribute to the desired distribution of wound exudate between the remotely located canister and the covering material. The area below the opening 111 preferably does not include any adhesive stripes. This is to prevent clogging and blockage of the tubing 105 and the coupling member 104.

[0132] "A plurality of stripes" means that the covering material includes at least two adhesive stripes. For example, the covering material can include 2 to 10, such as 2 to 6, adhesive stripes depending on the size of the covering material and the width of the stripes.

[0133] The adhesive stripe 114 can be arranged across the width of the covering material 100. Thus, the adhesive stripe 114 can be arranged to extend between the side edges of the permeable layer 113 and / or the absorbent structure 103. The stripes are preferably arranged at a right angle to the flow path of the exudate towards the tubing 105. Thus, the adhesive stripe 114 is arranged such that the exudate flowing into the covering material always encounters the adhesive stripe 114 when it is flowing towards the tubing 105.

[0134] The adhesive is preferably a hot melt adhesive. The width of the adhesive stripe can be in the range of 3 to 25 mm, such as 5 to 15 mm, such as 6 to 10 mm.

[0135] The distance between the adhesive stripes 114 can be 10 to 50 mm, such as 15 to 30 mm. The distance between the adhesive stripes 114 can be influenced by the size and shape of the covering material 100.

[0136] The permeable layer 113, the absorbent structure 103 and the liquid spreading layer 112 can be collectively referred to as the wound pad of the covering material.

[0137] Figure 3 conceptually shows a negative pressure wound therapy (NPWT) system according to the present disclosure.

[0138] The negative pressure wound therapy (NPWT) system 300 includes the NPWT dressing 100 according to the present disclosure. The dressing 100 is applied to the knee of the patient 115.

[0139] The NPWT system 300 includes the following: - the negative pressure wound therapy (NPWT) dressing 100 described above herein, and - a negative pressure source, and - remote fluid collection means 117 fluidly connected to the negative pressure source and the dressing 100.

[0140] The negative pressure source is a negative pressure pump adapted to establish a negative pressure when the pump is in an operating state. The negative pressure pump can be any type of pump that is biocompatible and maintains or draws in an appropriate and therapeutically effective vacuum level. Preferably, the negative pressure level to be achieved is in the range of about -2666.4 Pa (-20 mmHg) to about -39996.7 Pa (-300 mmHg). In embodiments of the present disclosure, a negative pressure range of about -10665.8 Pa (-80 mmHg) to about -23998.0 (-180), preferably about -13332.2 (-100) to -19998.4 Pa (-150 mmHg), more preferably -14665.5 (-110) to -18665.1 (-140 mmHg) Pa is used. In an embodiment, the negative pressure pump is a diaphragm type or peristaltic type pump.

[0141] The term "fluidly connected" as used herein should be construed broadly and can include any form of tubing, conduit, or pathway that provides fluid connection / communication between the remote fluid collection means 117 and the negative pressure source and the dressing 100.

[0142] The remote fluid collection means 117 can be any kind of fluid container, such as a canister. Alternatively, it may be an absorbent material present inside the NPWT dressing or the tubing of the NPWT system, or an absorbent structure disposed between the dressing or the dressing of the present disclosure and the canister. Generally, the remote fluid collection means 117 is a canister.

[0143] In FIG. 3, the negative pressure source is included inside the housing 116 of the portable negative pressure wound therapy (NPWT) device 118. The canister is preferably detachably connected to the housing 116.

[0144] In other words, the canister 117 is removably connected to the housing 116. The detachable connection may be by conventional means including friction fit, bayonet coupling, snap fit, locking claw connector, etc. The detachable configuration allows the user or caregiver to remove the canister 117, empty the collected liquid, and then reattach the canister 117 to the housing 116.

[0145] The canister 117 can be formed from, for example, molded plastic. The canister 117 is preferably at least partially transparent / translucent so that the user can view the inside of the canister 117 to assist in determining the remaining capacity of the canister 117.

[0146] For example, the internal volume of the canister 117 is 30 - 300 ml, such as 40 - 150 ml. The internal volume of the canister 117 can vary depending on the type of wound. In an embodiment, the canister 117 contains a liquid absorbent material. In a contemplated embodiment, at least 75% of the internal volume of the canister 117 is occupied by the liquid absorbent material.

[0147] The NPWT device 118 uses tubing 105 for the dressing 100It can be connected to. In the embodiment shown in FIG. 3, the NPWT system includes a connector unit 119 at a position between the dressing 100 and the NPWT device 118. The connector unit 119 can include a first connector portion (designated as 109 in FIG. 1) and a second connector portion (see 123 in FIG. 4). The connector portions 109 and 123 are preferably detachably connected so that the dressing can be disconnected from the NPWT device 118. This is beneficial in a portable NPWT system since the user may decide to disconnect the dressing from the device 118 when taking a shower by themselves or for some other reason.

[0148] In FIG. 3, the tubing 105 is a double conduit, while the second tubing 120 between the NPWT device 118 and the connector 119 is a single conduit. The NPWT system is by no means limited to such a configuration and may include a single conduit or a double conduit between the NPWT device 118 and the dressing 100. Similarly, the NPWT system is not limited to the use of the connector unit 119. The tubing 105 can be configured to extend all the way to the NPWT device 118 in an embodiment.

[0149] The NPWT system 300 preferably includes means for supplying air to the dressing at a flow rate of 2 to 7 ml / min during operation.

[0150] Preferably, the means for supplying air to the dressing is configured to supply air at a negative pressure of -10665.8 (-80) to -19998.4 (-150 mmHg), preferably -13332.2 (-100) to -17331.9 Pa (-130 mmHg) at a rate of 2 to 7 ml, preferably 3 to 5 ml.

[0151] In the NPWT system 300 shown in FIG. 3, ambient air is introduced into the system using a connector unit 119 (shown by arrow 121). For example, the first and / or second connector portions (109 and 123) include an air filter (not shown) configured to control the supply of air into the dressing 100 and / or the tubing 105. The first and / or second connector portions (109 and 123) can include, for example, an intake port with an air filter disposed therein.

[0152] The air filter preferably comprises a hydrophobic and porous material, where the pore size is in the range of 2 - 20 μm, preferably in the range of 5 - 12 μm. The pore diameter of the filter is measured in the uncompressed state.

[0153] The air filter preferably comprises polyethylene, preferably sintered polyethylene.

[0154] The sintered polyethylene filter has a repeating linear molecular structure -CH2-CH2. This structure is inert with strong molecular bonds and is characterized by improved chemical resistance, lightweight, thermoplasticity, and excellent filtration characteristics. The sintered polyethylene filter produces no toxic waste and is environmentally friendly as it can be rinsed and reused.

[0155] The air filter ensures that during operation, the supply of air is in the range of 2 - 7 ml / min at a negative pressure, for example, from -10665.8 Pa (-80 mmHg) to -19998.4 Pa (-150 mmHg), for example, from -13332.2 (-100 mmHg) to -17331.9 Pa (-130 mmHg).

[0156] It should be noted that air can be introduced into the system in an alternative manner and an air filter can be provided at an alternative location within the system. The regulation of the air supply can be controlled by the NPWT device 118 in embodiments.

[0157] In use, the dressing 100 is placed on the wound site of the user / patient, forming a sealed space. Tubes (105 and 120) are provided to fluidly couple the dressing 100 to the NPWT device 118, such as the inlet port of the NPWT device 118. At this time, the NPWT device 118 is actuated by the user / patient, for example, by pressing the start / stop button 122. Thereby, the negative pressure pump is actuated. When actuated, the negative pressure pump will start to discharge air through the sealed space formed by the canister 117, the tubes (120 and 105), and the dressing 100. Thus, a negative pressure is created inside the sealed space. If liquid is formed at the wound site, this liquid from the wound site can be "drawn in" at least partially from the wound site through the tubes (105 and 120) into the canister 117. The amount of liquid, i.e., exudate, withdrawn from the wound and collected in the canister 117 depends on the wound being treated and the type of wound dressing used. For example, more or less exudate will be drawn into the canister depending on the absorption capacity of the dressing 100. Within the framework of the present disclosure, a substantially equal balance in the liquid distribution is desired. For the purpose of ensuring that no liquid can pass from the canister 117 to the negative pressure pump, a suitable filter member (not shown) can be arranged between the canister 117 and the negative pressure pump.

[0158] The canister 117 may include an inlet port to enable connection to the tube 120. The connection between the inlet port and the tube 120 is preferably a sealed connection, thus ensuring that no leakage is formed at the inlet port during normal operation of the NPWT device 118. The tube 120 is preferably removably connected to the inlet port through conventional means including friction fitting, bayonet coupling, snap fitting, a connector with locking claws, etc. A similar sealed connection is also formed between the canister 117 and the negative pressure pump.

[0159] FIG. 4 shows a kit 400 according to an exemplary embodiment. The kit 400 includes at least one NPWT dressing 100 as described above.

[0160] The covering material includes the tubing 105. Preferably, the tubing 105 is pre - attached to the covering material, for example, using a coupling member 104 attached to the lining layer of the covering material 100. The pre - attachment of the tubing 105 enables the rapid assembly of the components of the system / kit.

[0161] The distal end of the tubing 105 is connected to a first connector portion 109. The kit can further include a negative pressure source disposed inside the housing 116. The kit can similarly include a canister 117. The canister may include a second tubing 120. The distal end of the second tubing 120 may include a second connector portion 123. The second connector portion 123 is configured to be connected to the first connector portion 109 associated with the tubing 105 of the covering material 100. The kit 400 can include additional components such as an additional battery 124 for powering the NPWT device 118 and an adhesive strip 125 for improving the adhesion between the edge portion of the covering material and the skin of the wearer.

[0162] The kit shown in FIG. 4 is adapted for home care but can be used equally advantageously in an environment such as a hospital or a care facility. The NPWT device is adapted to be carried by the user, for example, in a pocket, on a belt, a strap or the like. The covering material 100 and the other components of the kit 400 can be easily assembled by the user.

[0163] The components of the kit 400 can vary. For example, one kit may include all of the above - described components, while other kits may include only two or three components.

[0164] The kit 400 may include a plurality of NPWT covering materials as described above, optionally packaged together with a plurality of adhesive strips 125.

[0165] Accordingly, kit 400 includes the negative pressure wound treatment dressing described above and at least one additional component, where the additional component is selected from a negative pressure source, canister 117, battery 124, and / or adhesive strip 125.

[0166] The NPWT device 118 used within the kits (and within the NPWT system) of the present disclosure includes the features and components necessary to control the operation of the device. For example, the NPWT device may include a control unit electrically connected to a battery. Such a control unit may include a microprocessor, a microcontroller, a programmable digital signal processor, or another programmable device. Additionally, the NPWT device 118 can include at least one pressure sensor disposed in fluid communication with a negative pressure pump.

Example

[0167] Example 1: System Stability Comparative Test A wearing test was conducted using the dressing according to the present disclosure (Dressing A) and a reference dressing (Dressing B). Dressing A and Dressing B had a similar structure and differed only with respect to the backing layer. The dressings each included, from bottom to top, an adhesive skin contact layer including a polyurethane film and a silicone gel layer, a spacer fabric permeable layer, an absorbent structure (including a nonwoven liquid spreading layer, the above-described Airlaid SAP layer, and a tissue layer), a nonwoven liquid spreading layer, and a backing layer. Both dressings included pre-attached tubing including an air conduit and a fluid conduit. The characteristics of the backing layer are listed in Table 1 below.

[0168]

Table 1

[0169] The dressing material was applied to the subject's anterior knee with the foot bent at 120 degrees (the tubing of the dressing material points upward). Using each of the connector parts shown in Figure 1, the tubing was connected to a mobile negative pressure device. The pump used was a diaphragm pump. As disclosed in Figure 1, a canister configured to store 50 ml of liquid was connected to the pump. The connector part attached to the distal end of the tubing of the dressing material included an air filter, and ambient air was introduced into the connector and the system so that the supply of air to the dressing material (using an air conduit) would be within 2 - 7 ml / min during operation.

[0170] The pump was operated to apply a negative pressure of -16665.3 Pa (-125 mmHg) to the dressing material. The time Toff during the operation of the pump was recorded over the first 5 hours (0 - 5 hours and 3 - 5 hours respectively), which is an indication of the stability of the system and a means to ensure that no unwanted air is introduced into the system.

[0171] The test was conducted on 5 subjects, and the average Toff was recorded over the times of 0 - 5 hours and 3 - 5 hours.

[0172] The average Toff was 26 seconds for dressing material B and 35 seconds for dressing material A during the 0 - 5 hour period. This represents a 26% improvement. The improvement was even more significant during the 3 - 5 hour period, where Toff was 40% higher for the dressing material of the present disclosure. The results are shown in Figure 5 and Table 2 below. These results indicate that the properties of the backing layer affect the stability of negative pressure wound therapy. The system is stable and airtight, and the pump does not need to operate very powerfully.

[0173]

Table 2

[0174] Example 2; Liquid Distribution Comparative Test To test the liquid distribution between the covering material and the canister, a comparative test was conducted using three absorbent covering materials (Covering Material A, Covering Material C, and Covering Material D, respectively).

[0175] Covering Material A had the same structure as that described above. Covering Material C had the same layer structure as Covering Material A, but had a higher basis weight of the absorbent structure, and the amount and retention capacity of the superabsorbent particles per 1 cm 2 were different.

[0176] Covering Material D had the same overall layer structure but was different in terms of the absorbent structure. The absorbent structure of Covering Material D included an absorbent layer containing 40 wt% superabsorbent fibers (SAF) and 60 wt% polyester (polyethylene terephthalate) fibers, as well as a non-woven spreading layer. There were no superabsorbent particles in the absorbent structure of Covering Material D.

[0177] All the covering materials (A, C, and D) included a non-woven liquid spreading layer disposed on the absorbent structure. The non-woven liquid spreading layer contained 50 wt% viscose fibers and 50 wt% bicomponent fibers. For further details of the absorbent structure of the covering materials, refer to Table 3 below.

[0178]

Table 3

[0179] The retention capacity was measured as described in Example 3 below.

[0180] The pre-weighed dressing material was attached to a plexiglass plate sized larger than the dressing material area. The plexiglass plate had holes for liquid inflow. The dressing material was positioned such that the liquid inflow came within the central portion of the dressing material. Each dressing material included tubing connected to the mobile negative pressure device shown in Figure 1. The pump used was a diaphragm type pump. A canister configured to store 50 ml of liquid was used and connected to the pump disposed inside the housing disclosed in Figure 1. As described above, the dressing material and the NPWT device (including the canister and the pump) were connected by their respective connector parts. An air filter was placed inside the first connector part associated with the tubing of the dressing material. Ambient air was introduced into the connector such that the air supply to the dressing material was within the range of 2 - 7 ml / min. The pump was operated and a negative pressure of -16665.3 Pa (-125 mmHg) was applied to the dressing material.

[0181] Over 7 days at a flow rate of 300 ml (for dressings C and D) and over 9 days at a flow rate of 386 ml (for dressing A), the test liquid (horse serum) was added to the center of each dressing material. The negative pressure inside the dressing material was maintained at -16665.3 Pa (-125 mmHg) throughout the test period. After the test period, the wet weights of the dressing material and the canister were recorded. The distribution of the test liquid between each dressing material and the canister was calculated.

[0182] As can be seen in Figure 6, the liquid distribution between dressing A and the canister was 61:39, while for dressing C, the majority of the liquid was retained within the dressing material (90%), with only 10% being transferred to the canister. Dressing D had a dressing:canister liquid distribution of 34:66.

[0183] After the test periods (7 days and 9 days respectively), photographs of the dressing materials were taken. As can be seen in Figure 7a, dressing D had a relatively low liquid distribution within the dressing material structure. In other words, only a small portion of the absorption capacity of the dressing material was utilized. Instead, more exudate was transferred to the canister.

[0184] Figure 7b shows the coating material C, where most of the coating material had been used. Although not clearly visible from this figure, the coating material had a bulky and "blurred" appearance.

[0185] Figure 7c shows the coating material A after 9 days of liquid exposure. Most of the coating material was used to handle the liquid, and still, at least 40% of the exudate could be transferred to the canister. The desired liquid distribution between the fluid collection means (coating material and canister) was thus achieved.

[0186] Example 3: Retention Capacity of Coating Material Fluid retention capacity is defined as the ability of a coating material to hold liquid.

[0187] First, the theoretical maximum absorption amount was evaluated for the coating material samples. The maximum absorption capacity is the amount of liquid that the coating material can absorb when exposed to excess test liquid and without any applied load.

[0188] Coating material samples A, C, and D were punched out from the central part of the coating material to a predetermined size (5×5 cm = 25 cm 2 ) so that all the layers present in the coating material were used in the test.

[0189] The area and weight of the coating material samples (A, C, and D) in the dry state were recorded. Each coating material sample was immersed in sufficient test liquid (horse serum) in a bowl. A fine-mesh wire net was placed on top of the sample, and the adhesive skin contact layer was pushed down below the liquid surface with the fine-mesh wire net facing up. Each sample was covered with the test liquid throughout the absorption time and left to absorb for 60 minutes. When the absorption time was completed, the sample was vertically suspended at a corner of the coating material, and the liquid was allowed to flow out for 120 seconds. The samples were allowed to absorb the liquid for 60 minutes. When the absorption time was completed, they were held vertically at a corner, and the liquid was freely allowed to flow out from the specimen for 120 seconds (see the following figures). The maximum absorption capacity was recorded in units of grams of liquid for each sample.

[0190] After calculating the maximum absorption capacity, the same test (as described above) was conducted. The test liquid corresponding to 80% of the theoretical maximum absorption amount was absorbed by the sample. After an absorption time of 10 minutes, a pressure equivalent to 16665.3 Pa (125 mmHg) was applied to the sample with the wound side of the sample facing downward. The static pressure was maintained for 120 seconds. Then, the retention force was calculated as the weight of the horse serum retained in the sample after exposure to the static pressure. Thus, the retention ability is the ability of the product to retain liquid under a specified amount of pressure. The retention abilities regarding the coating materials A, C, and D are shown in Table 3 above.

[0191] Example 4: Effect of the liquid spreading layer in preventing backflow of liquid For the purpose of testing the ability of the coating material according to a preferred embodiment of the present disclosure (coating material A described above) and a reference coating material (coating material E) to address the backflow of exudate that may become a problem when the coating material is disconnected from the NPWT device, a comparative test was prepared using these coating materials. Coating material E had the same structure as coating material A, but lacked the liquid spreading layer of non-woven fabric between the backing layer and the absorbent structure. The tubing of each coating material was connected to a mobile negative pressure device using the same procedure as described in Examples 1-2.

[0192] The canister was filled with approximately 52 ml of horse serum (excess liquid). When the negative pressure of -16665.3 Pa (-125 mmHg) was stabilized, the canister was disconnected from the pump, and the excess liquid backflowed into the coating material. As can be seen in FIGS. 8a and 8b, the backflow of exudate was distributed over a larger surface area in the coating material of the present disclosure (coating material A) indicated as 100 in FIGS. 8a and 8b. In contrast, the backflow of exudate in coating material E (indicated as 801 in FIGS. 8a and 8b) did not spread significantly, and a larger proportion of the exudate was directly backflowed towards the wound site. Thus, the liquid spreading layer contributes to the uniform spreading and distribution of exudate in both directions.

[0193] The terms, definitions, and embodiments of all aspects of the present disclosure are applied with the necessary modifications added to other aspects of the present disclosure.

[0194] Although the present disclosure has been described in connection with its specific exemplary embodiments, many different modifications, corrections, etc. will become apparent to those skilled in the art.

[0195] By considering the drawings, the disclosure, and the appended claims, those skilled in the art can understand and achieve variations to the disclosed embodiments in practicing the present disclosure. Further, in the claims, the term "comprising (including ~)" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. In addition, as embodiments of the present invention, there are the following. [Aspect 1] In a negative pressure wound therapy (NPWT) dressing (100) including a backing layer (101), an adhesive skin contact layer (102), and an absorbent structure (103) disposed between the backing layer (101) and the adhesive skin contact layer (102); the adhesive skin contact layer (102) is configured to adhesively attach the dressing (100) to the skin surface in a detachable manner, and the backing layer (101) includes a coupling member (104) including a pipe (105) configured to connect the dressing (100) to a negative pressure source and a remote fluid collection means, and the backing layer (101) has a water vapor transmission rate (MVTR) in the range of 500 to 3500 g / m 2 / 24 h when measured by NWSP070.4R0(15). A negative pressure wound therapy (NPWT) dressing (100) characterized by this. [Aspect 2] The backing layer (101) has a water vapor transmission rate (MVTR) in the range of 600 to 2700 g / m 2 / 24 h. The negative pressure wound therapy (NPWT) dressing (100) according to Aspect 1. [Aspect 3] The pipe (105) includes a fluid conduit (106) configured to remove fluid from the dressing and an air conduit (107) configured to supply air to the fluid conduit (106) and / or the dressing (100). The negative pressure wound therapy (NPWT) dressing (100) according to Aspect 1 or 2. [Aspect 4] The backing layer (101) has a tensile strength in the machine direction (MD) and / or the machine cross direction (CD) of 30 to 70 MPa, preferably 35 to 55 MPa when measured by ISO527-3 / 2 / 200. The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 3. [Aspect 5] The backing layer (101) includes a thermoplastic elastomer, preferably thermoplastic polyurethane. The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 4. [Aspect 6] The backing layer (101) and the adhesive skin contact layer (102) are configured to extend beyond the peripheral portion of the absorbent structure (103) to form an edge portion (108) along the contour of the absorbent structure (103), and the adhesive skin contact layer (102) includes a plurality of apertures (110) within a region below the absorbent structure (103), but no apertures are provided within the region forming the edge portion (108). The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 5. [Aspect 7] The absorbent structure (103) contains superabsorbent particles in an amount of 10 to 20 mg / cm 2 , preferably 13 to 17 mg / cm 2 . The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 6. [Aspect 8] The absorbent structure (103) includes a first liquid spreading layer (103b), a superabsorbent layer (103a), and a second liquid spreading layer (103c), and the superabsorbent layer (103a) is disposed between the first and second liquid spreading layers (103b, 103c). The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 7. [Aspect 9] The absorbent structure (103) is embossed. The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 8. [Aspect 10] At least a part of the backing layer (101) and the absorbent structure (103) includes an opening (111), and the opening (111) is disposed under the coupling member (104). The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 9. [Aspect 11] Further includes a liquid spreading layer (112) disposed between the backing layer (101) and the absorbent structure (103); the liquid spreading layer (112) is configured to extend over at least 90% of the surface area of the absorbent structure (103) and is not provided with an opening. The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 10. [Aspect 12] Further includes a permeable layer (113) disposed between the adhesive skin contact layer (102) and the absorbent structure (103), and the permeable layer (113) includes a spacer fabric. The negative pressure wound therapy (NPWT) dressing (100) according to any one of Aspects 1 to 11. [Aspect 13] - A negative pressure wound therapy (NPWT) dressing (100) according to any one of aspects 1 to 12, - A negative pressure source, - Remote fluid collection means (117) fluidly connected to the negative pressure source and the dressing (100), A negative pressure wound therapy (NPWT) system (300) comprising. [Aspect 14] The remote fluid collection means (117) is a canister, and the canister and the negative pressure source are disposed inside the same device (118); the device (118) includes a housing (116), the negative pressure source is disposed within the housing, and the canister (117) is removably connected to the housing (116). The negative pressure wound therapy (NPWT) system (300) according to aspect 13. [Aspect 15] Means for supplying air to the dressing at a flow rate of 2 to 7 ml / min during operation. The negative pressure wound therapy (NPWT) system (300) according to aspect 13 or 14. [Aspect 16] A kit (400) comprising a negative pressure wound therapy (NPWT) dressing (100) according to any one of aspects 1 to 12 and at least one additional component selected from a negative pressure source, a canister (117), a battery (124) and / or an adhesive strip (125).

Claims

1. In a negative pressure wound therapy (NPWT) dressing (100) comprising a backing layer (101), an adhesive skin contact layer (102), and an absorbent structure (103) disposed between the backing layer (101) and the adhesive skin contact layer (102); the adhesive skin contact layer (102) is configured to adhesively attach the dressing (100) to the skin surface in a removable manner, the backing layer (101) and the adhesive skin contact layer (102) are configured to extend beyond the peripheral portion of the absorbent structure (103) to form an edge portion (108) along the contour of the absorbent structure (103), and although the adhesive skin contact layer (102) includes a plurality of apertures (110) in a region below the absorbent structure (103), no apertures are provided in the region forming the edge portion (108), A negative pressure wound therapy (NPWT) dressing, wherein the backing layer (101) includes a bonding member (104) including a tube (105) configured to connect the dressing (100) to a negative pressure source and a remote fluid collection means, and the backing layer (101) has a water vapor transmission rate (MVTR) in the range of 500 to 3500 g / m 2 / 24 h as measured by NWSP070.4R0(15). The negative pressure wound therapy (NPWT) dressing (100) is characterized by this.

2. The backing layer (101) has a water vapor transmission rate (MVTR) within the range of 600 to 2700 g / m 2 / 24 h, and the negative pressure wound therapy (NPWT) dressing (100) according to claim 1.

3. The tubing (105) includes a fluid conduit (106) configured to remove fluid from the dressing and an air conduit (107) configured to supply air to the fluid conduit (106) and / or the dressing (100). The negative pressure wound therapy (NPWT) dressing (100) according to claim 1 or 2.

4. The backing layer (101) has a tensile strength in the machine direction (MD) and / or the machine cross direction (CD) of 30 to 70 MPa when measured according to ISO 527-3 / 2 / 200. The negative pressure wound therapy (NPWT) dressing (100) according to any one of claims 1 to 3.

5. The backing layer (101) includes a thermoplastic elastomer. The negative pressure wound therapy (NPWT) dressing (100) according to any one of claims 1 to 4.

6. The absorbent structure (103) contains superabsorbent particles in an amount of 10 to 20 mg / cm 2 The negative pressure wound therapy (NPWT) dressing (100) according to any one of claims 1 to 5, wherein the absorbent structure (103) contains superabsorbent particles in an amount of 10 to 20 mg / cm.

7. The absorbent structure (103) includes a first liquid spreading layer (103b), a superabsorbent layer (103a), and a second liquid spreading layer (103c), and the superabsorbent layer (103a) is disposed between the first and second liquid spreading layers (103b, 103c). The negative pressure wound therapy (NPWT) dressing (100) according to any one of claims 1 to 6.

8. The absorbent structure (103) is embossed. The negative pressure wound therapy (NPWT) dressing (100) according to any one of claims 1 to 7.

9. At least a part of the backing layer (101) and the absorbent structure (103) includes an opening (111), and the opening (111) is disposed under the bonding member (104). The negative pressure wound treatment (NPWT) dressing (100) according to any one of claims 1 to 8.

10. Further includes a liquid spreading layer (112) disposed between the backing layer (101) and the absorbent structure (103); the liquid spreading layer (112) is configured to extend over at least 90% of the surface area of the absorbent structure (103) and is not provided with an opening. The negative pressure wound treatment (NPWT) dressing (100) according to any one of claims 1 to 9.

11. Further includes a permeable layer (113) disposed between the adhesive skin contact layer (102) and the absorbent structure (103), and the permeable layer (113) includes a spacer fabric. The negative pressure wound treatment (NPWT) dressing (100) according to any one of claims 1 to 10.

12. - The negative pressure wound treatment (NPWT) dressing (100) according to any one of claims 1 to 11, - A negative pressure source, - Remote fluid collection means (117) fluidly connected to the negative pressure source and the dressing (100), A negative pressure wound treatment (NPWT) system (300) including.

13. The remote fluid collection means (117) is a canister, and the canister and the negative pressure source are disposed inside the same device (118); the device (118) includes a housing (116), the negative pressure source is disposed in this housing, and the canister (117) is detachably connected to the housing (116). The negative pressure wound treatment (NPWT) system (300) according to claim 12.

14. Means for supplying air to the dressing at a flow rate of 2 to 7 ml / min during operation. The negative pressure wound treatment (NPWT) system (300) according to claim 12 or 13.

15. A kit (400) including the negative pressure wound treatment (NPWT) dressing (100) according to any one of claims 1 to 11 and at least one additional component selected from a negative pressure source, a canister (117), a battery (124), and / or an adhesive strip (125).

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