Negative pressure wound dressing management system

Abstract

A wound exudate management system includes a pump for generating negative pressure, a dressing for covering and protecting a user's wound, and a tube including an internal lumen, the tube disposed between the pump and the dressing such that the pump and the dressing are in fluid communication via the internal lumen. The dressing includes an adhesive layer for adhering the dressing proximate to the wound, a wound contact layer, a pressure distribution layer, a multi-layer absorbent material disposed between the wound contact layer and the pressure distribution layer, a backing layer having a first surface and a second surface, the first surface of the backing layer adjacent to and in contact with the pressure distribution layer and the adhesive layer, and a flexible connector disposed on the second surface of the backing layer.

Description

[0001] This application is a divisional application of Inventive Patent Application No. 201780042750.7, filed 9 May 2017, entitled "Negative Pressure Wound Dressing Management System".

[0002] Cross Reference to Related Applications

[0003] This application claims the benefit of United Kingdom Patent Application No. 1608099.6, filed 9 May 2016, and United States Provisional Patent Application No. 62 / 370,667, filed 3 August 2016, both of which are expressly incorporated by reference herein and as part of the present application. TECHNICAL FIELD

[0004] The present invention relates generally to wound dressing systems, and in particular to a wound dressing system for use with a negative pressure pump. Furthermore, the present invention relates to a dressing, system and kit for treating a wound, the dressing being used with a source of negative pressure to deliver negative pressure therapy. The dressing is suitable for use in treating a variety of wounds, including chronic and acute types, including infected wounds, venous ulcers, diabetic ulcers, burns and surgical wounds. BACKGROUND

[0005] Wound dressings are known and are generally suitable for use in treating a variety of wounds, including chronic and acute wound types, such as infected wounds, venous ulcers, diabetic ulcers, burns and surgical wounds.

[0006] Negative pressure has been used to treat a variety of chronic and acute wounds. Negative pressure can promote healing of a wound through a number of mechanisms, including removal of excess exudate, reduction of surrounding oedema and increased perfusion. In combination with the physical forces exerted by the negative pressure pulling the edges of the wound together, this can result in improved wound outcomes. Conventional devices are often large and require the use of complex equipment, which can include a suction pump to generate negative pressure, a pressure regulator, a canister to collect wound exudate and a wound dressing to deliver therapy to the wound site. As a result, such devices can be bulky, costly and confine the patient to bed, or at least render the patient immobile and unable to carry out their daily activities.

[0007] Recently, portable systems have been developed that include a device that manages exudate produced by a wound by collecting exudate within a wound dressing (typically in an absorbent material) and by evaporation through the dressing. Such systems mean that a separate collection canister can not be an essential part of the system. Such a system is described in EP 2021046. The advantage of not requiring a canister is that the device is smaller in volume and easier to carry. The disadvantage of such a device is that if the dressing exceeds its fluid handling capacity, exudate can be wicked from the absorbent material and into the pump. The presence of exudate in the pump will eventually cause it to fail and require replacement. The treatment provided by the system can also not be optimal as there can be an excess of exudate accumulating at the wound interface. To prevent the pump with exudate from fouling, it is known to provide a barrier between the absorbent material and the pump. However, a liquid barrier does not provide an indication to the user or carer that the dressing has exceeded its fluid handling capacity and needs to be changed.

[0008] In those devices where a canister is present, the user or carer is given a visual indication of how much exudate is being produced by the wound by the presence of exudate in the canister. However, the presence of exudate in the canister only occurs when the dressing exceeds its fluid handling capacity. There is no early warning that the dressing needs to be changed.

[0009] There is a need to indicate when the dressing has reached or exceeded its fluid handling capacity.

[0010] In addition, existing portable negative pressure wound dressing systems often include rigid dressings and connecting components that adversely affect the utility of the system and the comfort of the user. In addition, existing portable negative pressure wound dressing systems do not take advantage of absorbent materials and additional wound dressing components that are arranged to maximize the management of wound exudate within the dressing. Therefore, there is a need for a portable exudate management system that incorporates these and other features. The present disclosure seeks to overcome the limitations and other drawbacks of the prior art and provide new features that have not yet been obtained. A full discussion of the features and advantages of the present disclosure is deferred to the following detailed description, which proceeds with reference to the accompanying drawings. SUMMARY

[0011] In one embodiment, the present disclosure provides a negative pressure wound dressing for applying negative pressure to a wound, comprising: an absorbent layer capable of absorbing exudate from the wound and allowing fluid to pass through the wound; an outer cover layer covering the side of the absorbent layer furthest from the wound, the cover layer being adapted to enable negative pressure to be applied to the wound and having a port; a conduit having a proximal end connected to the port and a distal end, the dressing being provided with a passageway for fluid to flow from the wound, through the absorbent layer, the port and to the distal end of the conduit; and an indicator device located in the passageway at a position between the absorbent layer and the distal end of the conduit, the indicator device being capable of absorbing exudate to indicate the presence of exudate on the side of the absorbent layer furthest from the wound.

[0012] In a further embodiment, the present disclosure provides a negative pressure wound dressing for applying negative pressure to a wound, comprising: an absorbent layer capable of absorbing exudate from the wound and allowing fluid to pass through the wound; an outer cover layer covering the side of the absorbent layer furthest from the wound, the cover layer being adapted to enable negative pressure to be applied to the wound and having a port; a conduit having a proximal end connected to the port and a distal end, the dressing being provided with a passageway for fluid to flow from the wound, through the absorbent layer, the port and to the distal end of the conduit; an indicator device located in the passageway at a position between the absorbent layer and the distal end of the conduit, the indicator device being capable of absorbing exudate to indicate the presence of exudate on the side of the absorbent layer furthest from the wound; and a negative pressure source connected to the distal end of the conduit.

[0013] Preferably, the negative pressure source is capable of generating a minimum of 75 mmHg and a maximum of 125 mmHg at the wound.

[0014] In some embodiments of the disclosed subject technology, a wound exudate management system is provided. In one implementation, the wound exudate management system includes: a pump for generating negative pressure; a dressing for covering and protecting a wound, the dressing including an adhesive layer for adhering the dressing proximate to the wound, a wound contact layer for contacting the wound, a pressure distribution layer, a multi-layer absorbent material disposed between the wound contact layer and the pressure distribution layer, and a backing layer having a first surface and a second surface, the first surface of the backing layer being adjacent to and in contact with the pressure distribution layer and the adhesive layer; a pressure tube having an internal lumen, the pressure conduit being disposed between the pump and the dressing such that the pump and the dressing are in fluid communication via the internal lumen; and a flexible connector connected to the second surface of the backing layer.

[0015] The disclosed technology also relates to a dressing for covering and protecting a wound. The disclosed technology also relates to a wound exudate management system comprising a dressing for covering and protecting a wound, the dressing comprising: a wound contact layer having a first surface and a second surface, the wound contact layer further having a peripheral region and a central region, wherein the first surface of the wound contact layer contacts a wound when the dressing is adhered to skin proximate the wound; a pressure distribution layer having a peripheral region and a central region; a plurality of layers of absorbent material disposed between the second surface of the wound contact layer and the pressure distribution layer; and an envelope formed by joining the peripheral region of the pressure distribution layer with the peripheral region of the second surface of the wound contact layer, the plurality of layers of absorbent material being substantially disposed within the interior cavity of the envelope. Alternatively, the envelope can be formed by joining the peripheral region of the thermoplastic spunlace layer connected to the pressure distribution layer with the peripheral region of the nonwoven spunlace layer connected to the second surface of the wound contact layer, such that the plurality of layers of absorbent material are substantially disposed within the interior cavity of the envelope.

[0016] The disclosed technology also relates to a wound exudate management system further comprising a thermoplastic spunlace layer connected to the pressure distribution layer and a nonwoven spunlace layer connected to the wound contact layer, and wherein the envelope is formed by joining the peripheral portion of the thermoplastic spunlace layer and the nonwoven spunlace layer, wherein the interior cavity of the envelope is formed by the nonwoven spunlace layer and the thermoplastic spunlace layer, and wherein the plurality of layers of absorbent material are substantially disposed in the interior cavity of the envelope.

[0017] The disclosed technology also relates to a wound exudate management system comprising: a dressing for covering and protecting a wound, the dressing comprising a wound contact layer, a backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer; a flexible connector having an interior cavity, the flexible connector being secured to the backing layer of the dressing; an indicator between the backing layer and the flexible connector; a tube having an interior cavity, the catheter being connected to the flexible connector, wherein the interior cavity of the flexible connector and the interior cavity of the catheter are in fluid communication; and a pressure transmitting member disposed within the interior cavity of the catheter.

[0018] The disclosed technology also relates to a wound exudate management system comprising: a pump for generating negative pressure; a dressing for covering and protecting a wound, the dressing comprising a wound contact layer, a backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer; a tube connecting the pump and the dressing, the catheter having an interior cavity for placing the pump and the dressing in fluid communication via the interior cavity; and a series of one-way valves between the pump and the dressing for maintaining negative pressure within the dressing when the pump is disconnected from the catheter.

[0019] The disclosed technology also relates to a wound exudate management system comprising: a pump for generating negative pressure; a dressing for covering and protecting a wound; a tube comprising a lumen, the tube being disposed between the pump and the dressing such that the pump and the dressing are in fluid communication via the lumen of the tube; and a multi-layered absorbent material disposed in the dressing, wherein the absorbent material has fibers that swell upon contact with wound exudate to control the flow of wound exudate through a portion of the dressing.

[0020] In any of the wound exudate management systems described above, the system can be adapted to allow fluid communication between the wound and the source of negative pressure, e.g., the pump. Typically, a fluid communication pathway is provided from the wound, through the wound contact layer, and through the one or more layers of absorbent material disposed in the dressing, to the source of negative pressure. The fluid communication pathway can optionally extend through the opening in the backing layer to the lumen of the tube via the lumen or conduit of the flexible connector. In the presence of an indicator, e.g., an absorption indicator member, the fluid communication pathway can also extend through the indicator.

[0021] Typically, the flexible connector is elongate, having a lumen or conduit that runs parallel to a longitudinal axis of the flexible connector, wherein the flexible connector is attachable to the opening in the backing layer of the dressing along a direction such that the longitudinal axis of the flexible connector is generally parallel to the plane of the backing layer. The flexible member can include a head for securing to the backing layer via adhesive or other means. Typically, the fluid communication pathway extends from the lumen or conduit of the flexible connector through the opening in the backing layer in a direction generally perpendicular to the longitudinal axis of the flexible connector. Once secured, a liquid-tight seal can be formed between the flexible connector and the backing layer.

[0022] In any of the embodiments described above, the presence of an indicator device can have the advantage of giving the user or caregiver an indication that the dressing needs to be changed. The indicator device allows the user or caregiver to change the dressing and prevent the pump from fouling. The presence of exudate occurs on the side of the absorbent layer furthest from the wound when the absorbent layer has absorbed a significant amount of exudate. If the indicator device is located in the conduit of the dressing and is triggered by the absorption of exudate, the exudate is not only present on the side of the absorbent layer furthest from the wound, but also exudes through the cover layer and into the conduit. It gives the user or caregiver a pre-warning that the fluid handling capacity of the dressing has been or will be reached shortly and suggests to change the dressing. The indicator device can indicate that the dressing has reached its fluid handling capacity and it is possible that exudate exudes from the dressing, into the conduit and eventually into the pump, which is undesirable.

[0023] The indicator device can be visual, or can cause an audible alarm or other signal. Preferably, the indicator device is visual and is positioned so that it can be seen by the user of the dressing. For example, the visual indicator device can be located in the port in the cover layer, or it can be located in the conduit or in both the port and the conduit. Similarly, in a wound exudate management system, the visual indicator device can be positioned through an opening in the backing layer and / or can be located in the lumen of the flexible connector or in the conduit. Preferably, the visual indicator device is a gel-forming absorbent that visually indicates that it has absorbed exudate by forming a gel. If the exudate is colored, the gel will also be colored and add a visual indication. Alternatively, the visual indicator device can indicate that it has absorbed exudate by changing color, for example by activating a dye in the indicator device.

[0024] Preferably, the indicator device is provided by a gel-forming fiber. By gel-forming fiber is meant a hygroscopic fiber that becomes wet and slippery or gel-like upon absorbing wound exudate. The gel-forming fiber can be of the type that retains its structural integrity upon absorbing exudate, or can be of the type that loses their fibrous form and become an amorphous or structureless gel. The gel-forming fiber is preferably a sodium carboxymethyl cellulose fiber, a chemically modified cellulose fiber, an alkyl sulfonate modified cellulose fiber such as those described in WO2012 / 061225, a pectin fiber, an alginate fiber, a chitosan fiber, a hyaluronic acid fiber, or other polysaccharide fiber derived from a resin. The cellulose fiber preferably has a degree of substitution of at least 0.05 carboxymethyl groups per glucose unit. The gel-forming fiber preferably has an absorbency of at least 2 grams of a 0.9% saline solution per gram of fiber (measured by free swell method).

[0025] The gel-forming fibres are preferably chemically modified cellulose fibres in the form of a fabric and in particular chemically modified cellulose fibres in the form of carboxymethylated cellulose fibres as described in PCT WO 00 / 01425 by Azko Nobel UK Limited. In this way, the indicator device can be provided by a layer of gel fibres, preferably located in the port of the cover layer or can be provided as a layer of fibres in the conduit. When present in the conduit, the layer of fibres can also serve to keep the conduit open for fluid passage in the event that the conduit is kinked or otherwise restricted due to the user lying or leaning. The carboxymethylated cellulose fabric preferably has a degree of substitution of 0.12 to 0.35 as measured by IR spectroscopy (as defined in WO 00 / 01425) and more preferably has a degree of substitution of 0.20 to 0.30. Particularly preferred fabrics can have an absorbency as defined above of between 10 g / g sodium chloride / calcium chloride and 30 g / g sodium chloride / calcium chloride as measured by the method described in Part 3.2 of the "Test methods for primary wound dressings" of the "Free swell absorptive capacity" of BS EN 13726-1 (2002). Particularly preferred fabrics have an absorbency of 15 g / g to 25 g / g, most preferably 15 g / g to 20 g / g sodium chloride / calcium chloride as measured by the method described above.

[0026] The cellulose fabric preferably consists only of cellulose fibres, but can contain a proportion of non-cellulose textile fibres or gel-forming fibres. The cellulose fibres are of a known type and can include continuous filament yarns and / or staple fibres. Carboxymethylation is typically carried out by contacting the fabric with alkali and a carboxymethylation agent such as chloroacetic acid in an aqueous system. The fabric is preferably of a non-woven type to reduce shedding in the wound when the dressing is cut. Preferably, the fabric is hydro-entangled and thus includes a series of pores on a microscopic scale.

[0027] The absorbent layer of the dressing is able to absorb exudate from the wound and allow fluid to pass through the wound. Although the absorbent layer can comprise any absorbent capable of absorbing exudate whilst allowing fluid to pass through it, for example a foam, a sponge or a fibrous base material, preferably the absorbent layer is provided by gel-forming fibres of the same type or different types, such as those used by the indicator device. Gel-forming fibres are hygroscopic fibres which become wet, slippery or gel-like when they absorb wound exudate, thus reducing the tendency for surrounding fibres to stick to the wound. The gel-forming fibres are preferably spun carboxymethylcellulose sodium fibres, chemically modified cellulose fibres, alkylsulphonate-modified cellulose fibres such as those described in WO2012 / 061225, pectin fibres, alginate fibres, chitosan fibres, hyaluronic acid fibres or other polysaccharide fibres derived from resins or fibres. The cellulose fibres are preferably lightly substituted with at least 0.05 carboxymethyl groups per glucose unit, more preferably lightly substituted such that the absorbency of the fibres is limited. The gel-forming fibres preferably have an absorbency of at least 2 grams of 0.9% saline solution per gram of fibre (measured by the method described above), but less than 30 grams of 0.9% saline solution per gram of fibre. The gel-forming fibres are preferably carboxymethylated cellulose fibres as described in PCT WO00 / 01425 by Azko Nobel UK Limited, which describes carboxymethylated cellulose fabrics slightly and more preferably of the type used in the indicator device. The gel-forming fibres are preferably lightly carboxymethylated to reduce the tendency for the absorbent layer to gel up and block the channels for fluid from the wound, through the absorbent layer, the port and to the distal end of the conduit.

[0028] Preferably, the absorbent layer is provided with fenestrations to help apply negative pressure to the wound and to maintain channels for fluid from the wound through the absorbent layer. Typically, however, fenestrations are provided only in the inner absorbent layer. The outer absorbent layers, including those in direct contact with the wound, typically do not have mechanically added fenestrations, however, they do have openings between the fibres.

[0029] Although the absorbent layer can be in direct contact with the wound, preferably the dressing comprises a wound contact layer positioned between the wound and the absorbent layer. The wound contact layer is able to absorb exudate from the wound and pass it to the absorbent layer. Like the absorbent layer, the wound contact layer is able to allow fluid to pass through it so that negative pressure can be applied to the wound and channels for fluid from the wound to the distal end of the conduit can be maintained.

[0030] Preferably, the wound contact layer comprises gel-forming fibres of the same or similar type as those comprising the absorbent layer, but the wound contact layer can be reinforced to increase its integrity and the integrity of the dressing. For example, the wound contact layer can be of the type described in EP1904011 and comprise gel-forming fibres in the form of a mat, longitudinal stitching made of cellulose or nylon or polyolefin yarn to increase the integrity of the layer. Preferably, the wound contact layer is porous to maintain a passage for fluid from the wound to the distal end of the conduit.

[0031] The outer cover of the dressing is a bacterial and viral barrier which is preferably resistant to the ingress of liquid and air but allows the transmission of moisture. In this way, the outer cover enhances the overall fluid handling capability of the dressing by enabling the application of negative pressure to the wound whilst allowing moisture to escape through the cover. The outer cover is for example a layer which can have an MVTR of at least 10,000 g / m 2 per 24 hours or an MVTR in the range of 10,000 g / m 2 to 50,000 g / m 2 per 24 hours, measured by the method described in the Test methods for primary wound dressings Part 2 Moisture vapour transmission rate of permeable film dressings of BS EN 13726-2 2002. The cover layer can be in the form of a polyurethane film, for example Epurex 912T / 129 manufactured by Covestro, or Inspire 2350 manufactured by Coveris, or Medifilm 426 manufactured by Mylan.

[0032] The cover layer is provided with a port for connection to the conduit. The port is preferably located on the part of the cover layer which overlies the absorbent layer but towards the periphery of the absorbent layer so that it is not directly vertically aligned with the centre of the dressing (or wound when in use). This helps to spread the exudate over the full extent of the absorbent layer.

[0033] The conduit of the dressing is preferably a transparent channel that is fixed at its proximal end to the outside of the cover layer to surround the port in the cover layer from above. In this way, the user can see the visual indicator if it is located in the port in the cover layer and / or in the conduit itself. Similarly, where the wound exudate management system comprises a flexible connector, the flexible connector can be partially or fully transparent in order to allow the user to see the visual indicator. Typically, the head of the flexible connector is transparent. The conduit of the dressing can comprise a connector at its distal end for connecting the dressing to a source of negative pressure, such as a pump. Preferably, the connector is a luer lock to facilitate a secure connection to the pump and to maintain negative pressure on the wound while the pump is temporarily disconnected. The connector preferably comprises a one-way lock to help maintain negative pressure. The visual indicator can be located in the conduit and can be in the form of a knitted cylinder of gel-forming fibres or the like. To prevent collapse, the conduit can comprise an inner cylinder of nylon fibres to maintain the openness of the conduit to fluid.

[0034] The dressing can further comprise a distribution layer, such as a pressure distribution layer, between the absorbent layer and the outer cover layer, which is gas permeable and liquid permeable and in particular moisture vapour permeable and serves to help exudate enter a greater area of the absorbent layer by allowing it to diffuse under the distribution layer. The distribution layer also serves to even out the negative pressure applied to the wound across the dressing. The distribution layer preferably distributes exudate and negative pressure across the dressing. In this way, the absorption of exudate by the absorbent layer is maximised and the transfer of negative pressure to the wound is optimised before the exudate leaves the absorbent layer and activates the indicator device. The distribution layer is preferably a foam layer, such as a polyester foam of the type XD4200AS manufactured by Caligen or other suitable reticulated foam.

[0035] The dressing can also comprise a further optional layer, such as an adhesive layer, for adhering the dressing to the skin around the wound to form a liquid-tight seal. The adhesive layer can be applied to the side of the dressing closest to the wound and can be provided with perforations to help the transport of exudate and fluid through the dressing. The adhesive layer can also be applied to any other layer to provide an island configuration, such as to the cover layer.

[0036] It is to be understood that the present technology is not limited to the embodiments specifically described hereinabove, which are presented by way of example only and that various modifications, well known per se to those skilled in the art, can be made in the embodiments without departing from the scope of the present technology. It is contemplated that the present technology can be practiced with other and different configurations, omissions, substitutions, and changes of procedure, without departing from the scope of the present technology. Accordingly, the detailed description is to be regarded as merely illustrative of the present technology, rather than restrictive, and all changes coming within the scope of the present technology are intended to be embraced therein. BRIEF DESCRIPTION OF DRAWINGS

[0037] For an understanding of the present disclosure, reference will now be made, by way of example, to the accompanying drawings in which embodiments and examples of the present disclosure are illustrated and will be described in the following detailed description.

[0038] Figure 1 is a top view of a wound exudate management system according to an example embodiment of the present disclosure, particularly showing a pump, a dressing, and a tube, among other features.

[0039] Figure 2 is a top view of a wound exudate management system according to an example embodiment of the present disclosure, particularly showing a dressing and a portion of a flexible connector of the wound exudate management system.

[0040] Figure 3A is a cross-sectional view of a wound exudate management system according to an example embodiment of the present disclosure, taken about line Figure 2 3-3 of FIG. 3, particularly showing a dressing, a portion of a flexible connector, and various component elements of the dressing.

[0041] Figure 3B is an alternative embodiment of a cross-sectional view of a wound exudate management system according to an example embodiment of the present disclosure, taken about line Figure 2 3-3 of FIG. 3, showing a dressing, a portion of a flexible connector, and various component elements of the dressing.

[0042] Figure 4 is an enlarged cross-sectional view of a wound exudate management system of Figure 3A FIG. 4, particularly showing the area indicated by arrow 4-4.

[0043] Figure 5A is an exploded perspective view of a wound exudate management system according to an example embodiment of the present disclosure.

[0044] Figure 5B is an alternative embodiment of an exploded perspective view of a wound exudate management system of the present disclosure.

[0045] Figure 6 is a bottom view of a wound exudate management system according to an example embodiment of the present disclosure, particularly showing a removable cover and a portion of a flexible connector of the wound exudate management system.

[0046] Figure 7 is a top view of a releasable connector of a wound exudate management system according to an example embodiment of the present disclosure, particularly showing the releasable connector in a connected state.

[0047] Figure 8 is a top view of a releasable connector of Figure 7 FIG. 11, particularly showing the releasable connector in a disconnected state. DETAILED DESCRIPTION

[0048] While the wound exudate management systems discussed herein can be implemented in many different forms, a preferred embodiment is shown in the drawings and will be described in detail herein, with the understanding that the present description is to be considered as an exemplification of the principles of the wound exudate management systems, and is not intended to limit the broad aspects of the disclosure to the embodiments illustrated.

[0049] Referring now to the drawings, and more particularly to Figure 1 , one embodiment of a wound exudate management system 10 is shown. The wound exudate management system 10 of this embodiment has a wound dressing 14, a pump 18, and a tube 22 (also referred to as a pressure tube 22). Generally, the wound exudate management system 10 facilitates wound healing and wound protection. The dressing 14 is applied to the skin of a user, as described below, and the system 10 utilizes negative pressure generated by the pump 18 to assist in wound healing. The dressing 14 and the pump 18 are fluidly connected by the tube 22. Negative pressure generated by the pump 18 is delivered through the tube 22 to the dressing 14, enabling the dressing 14 to employ negative pressure to enhance wound healing.

[0050] In various embodiments, the pump 18 operates to generate negative pressure in response to various user inputs. In one embodiment, a user control for the pump 18 is provided on and / or remote from the pump 18. The user control can be one or more of a button, a switch, a lever, a sensor, or any other control device. It should be understood that any ordinary user control is within the scope of the present disclosure. The pump 18 can also have one or more indicators 34a, 34b, 34c provided on the pump 18 for informing the pump user of the current operating status, condition, and battery life of the pump 18, among other things. The indicators 34a-c can be lights including light emitting diodes (LEDs), although any other type of indicator can be used, such as a speaker for producing an audible sound, or a motor with a radially asymmetric flywheel for producing a vibration. Instructional indicia 36a, 36b, 36c can be associated with one or more of the indicators 34a-c for informing the user of the importance of the operation of the particular indicator 34a-c. However, in some embodiments, the pump 18 operates without user input and generates negative pressure in response to a timer, a remote signal, a sensor reading, or other stimulus.

[0051] In one embodiment, the indicators 34a-c for the pump 18 are preferably not illuminated prior to the pump 18 being operated. In this state, the pump 18 generally does not produce negative pressure, which can correspond to the pump 18 being in an off state. Further, in one embodiment, when all of the indicators 34a-c are transitioned to an illuminated state, the pump 18 is preferably in a ready state and ready for use. Further, in one embodiment, when one indicator 34a remains in an illuminated state and the remaining indicators 34b and 34c are transitioned to a non-illuminated state, this indicates that the pump 18 is in an operating state. Normal operation of the pump 18 can include generation of negative pressure, alternating cycles of negative pressure generation, and / or no generation of negative pressure. The pump 18 can transition between one or more of the off state, the ready state, and the operating state due to manipulation of the user controls. Manipulation of the user controls to change the pump state can include and / or require manipulation of the user controls for a predetermined period of time.

[0052] In the operating state, in a preferred embodiment, the pump 18 generates a minimum pressure of 75 mmHg at the wound and a maximum pressure of 125 mmHg at the wound, however, alternating pressures can be generated by the pump 18. In one embodiment, the pump 18 generates negative pressure until a first pressure threshold is reached. The first pressure threshold can be, for example, a value between 75 mmHg and 125 mmHg, including the end values. The pump 18 can then refrain from generating negative pressure until a second threshold pressure is reached, at which time the pump 18 can generate negative pressure until the first pressure threshold is again reached. Alternating operation of the pump is permitted.

[0053] In one embodiment, as shown in Figure 1 the pump 18 is connected to the pressure tube 22 using a pump connector 38. The pump connector 38 can allow for selective separation of the pump 18 and the tube 22.

[0054] In one embodiment, the conduit 22 includes a distal conduit portion 40 and a proximal conduit-like portion. The proximal conduit-like portion can be an extension of a flexible connector 50. A separable connector 44 can connect the distal tube portion 40 and the proximal conduit-like portion, as shown in Figure 7 and 8 The pump connector 38 connects one end of the conduit 22, preferably the distal conduit portion 40 of the conduit 22, to the pump 18, as shown in Figure 1 However, in an alternative embodiment not shown, the pump connector 38 can connect the proximal conduit-like portion to the pump 18. In one embodiment, the distal tube portion 40 forms a portion of the pressure tube 22 and can be flexible, transparent, partially transparent, and / or formed of a polymer, metal, metal alloy, or any other suitable material.

[0055] Turning to the figures, reference is made to Figure 3A and Figure 4In one embodiment, the flexible connector 50 is structurally connected to the dressing 14 and also includes a flexible connector cavity 54. The flexible connector cavity 54 is disposed within a portion or all of the flexible connector 50 and allows fluid communication between the pump 18 and the dressing 14. A flexible connector aperture 60 allows fluid communication between the flexible connector cavity 54 and the dressing 14. The flexible connector 50 may include a lower flexible connector portion 66 and an upper flexible connector portion 67. The lower flexible connector portion 66 and the upper flexible connector portion 67 may be joined by welding, adhesive, or any other joining technique to form the flexible connector 50. The flexible connector 50 may preferably be formed of polyvinyl chloride, polyurethane, or any other suitable material. In one embodiment, the flexible connector 50 has a generally flat outer surface.

[0056] In one embodiment, a pressure delivery structure 62 is disposed within the flexible connector cavity 54. When the flexible connector 50 is made of a thin-walled flexible material, the pressure delivery structure 62 enables the flexible connector 50 to deliver fluid flow and / or pressure within the flexible connector cavity 54 without collapsing, thereby allowing the dressing 14 to experience or exhibit negative pressure generated by the pump 18. The pressure delivery structure 62 may include various materials, including but not limited to nylon. Furthermore, the pressure delivery structure 62 may include a lattice structure 53. The shape, material, and structure of the pressure delivery structure 62 enable continued flow along the flexible connector 50, which may be limited by the shape, flexibility, material, or structure of the flexible connector 50 due to the negative pressure generated by the pump 18 and due to the use and positioning of the general wound exudate management system 10.

[0057] like Figure 3A , 4 As best shown in 5A, dressing 14 preferably includes an indicator 70, which in one embodiment is an upper absorbent indicator member 70 formed of an absorbent material. The indicator 70 can generate signals, such as visual, auditory, and vibrational signals. When the indicator 70 is made of an absorbent material, the absorbent material may include gel-forming fibers, which may be hygroscopic fibers that become moist, smooth, or gel-like upon ingestion of wound exudate or other fluids. The gel-forming fibers may maintain their structural integrity while absorbing exudate, or they may lose their fibrous form and become amorphous or unstructured gels. In some embodiments, the gel-forming fibers are sodium carboxymethyl cellulose fibers, chemically modified cellulose fibers, alkyl sulfonate modified cellulose fibers such as those described in WO2012 / 061225, pectin fibers, alginate fibers, chitosan fibers, hyaluronic acid fibers, other polysaccharide fibers, or fibers derived from resins.

[0058] The cellulosic fibers illustratively have a degree of substitution of at least 0.05 carboxymethyl groups per glucose unit. The gel-forming fibers can have an absorbency of at least 2 grams of 0.9% saline solution per gram of fiber (measured by the free swell method) but less than 30 grams of 0.9% saline solution per gram of fiber.

[0059] The gel-forming fibers are preferably chemically modified cellulosic fibers in the form of a fabric and in particular carboxymethylated cellulosic fibers as described in PCT WO 00 / 01425 by Azko Nobel UK Limited. The carboxymethylated cellulosic fabric illustratively has a degree of substitution of 0.12 to 0.35 as measured by IR spectroscopy (as defined in WO 00 / 01425) and can also have a degree of substitution of 0.20-0.30. The carboxymethylated cellulosic fabric can be formed by carboxymethylating a woven or nonwoven cellulosic fabric to increase the absorbency. The fabric can have an absorbency between 10 g / g sodium chloride / calcium chloride and 30 g / g sodium chloride / calcium chloride as measured by the method described in Part 3.2 of the Free swell absorptive capacity of BS EN 13726-1 (2002) Test methods for primary wound dressings. Some fabrics have an absorbency of 15 g / g to 25 g / g or 15 g / g to 20 g / g of sodium chloride / calcium chloride. The gel-forming fibers can be lightly carboxymethylated to reduce the tendency of the absorbent material to block the gel and prevent fluid passage through the dressing 14.

[0060] The cellulosic fabric can consist solely of cellulosic fibers but can also contain non-cellulosic textile fibers or gel-forming fibers. The cellulosic fibers can be of a known type and can include continuous filament yarns and / or staple fibers. The carboxymethylation can be performed by contacting the fabric with a base and a carboxymethylation agent such as chloroacetic acid in an aqueous system. The fabric can be of a nonwoven type and can be further hydroentangled, thus including a series of pores on a microscopic scale. The absorbent material can also include any absorbent material capable of absorbing exudate while allowing fluid passage such as a foam, a sponge or a fiber-based material.

[0061] The upper absorbent indicator member 70 is preferably above the backing layer 82 and can be adjacent to, connected with, and / or in contact with the flexible connector 50 and can also be adjacent to the flexible connector aperture 60. As Figure 4As best shown, in one embodiment, the first side of the upper adhesive 74 adheres to both the upper absorbent indicator member 70 and the lower flexible connector portion 66 of the flexible connector 50. The lower flexible connector portion 66 is preferably adhered from a portion of the first side of the upper adhesive 74 to a portion of the upper adhesive 74 to which the upper absorbent indicator member 70 is adhered, along a radially outward direction. The upper adhesive 74 also has an upper adhesive aperture 78 extending from the first side of the upper adhesive 74 to the second side of the upper adhesive 74 and disposed adjacent to the upper absorbent indicator member 70 to limit interference with the vacuum effect taken by the upper absorbent indicator member 70.

[0062] In one embodiment, a backing layer 82 is disposed between both the indicator member 70 and the flexible connector 50 and the plurality of absorbent layers of the dressing 14. In one embodiment, the backing layer 82 is disposed beneath the upper adhesive 74. The backing layer 82 preferably has a backing layer aperture 86 disposed through the backing layer 82 and extending from a first surface 83 of the backing layer 82 to a second surface 84 of the backing layer. Thus, in one embodiment, the upper adhesive 74 is disposed adjacent to the second surface 84 of the backing layer 82. Upon assembly, the aperture 86 of the backing layer 82 is disposed adjacent to the aperture 78 in the upper adhesive 74. In some embodiments, the backing layer 82 is a bacteria and virus barrier layer that resists the ingress of liquids and air while allowing the transmission of moisture. In this way, the backing layer 82 enhances the overall fluid handling capabilities of the dressing 14 by allowing water vapor to escape through the backing layer 82 while enabling the application of negative pressure to the wound or dressing 14. The backing layer 82 can have a moisture vapor transmission rate (MVTR) of at least 10,000 g / m 2 per 24 hours or a moisture vapor transmission rate (MVTR) in the range of 10,000 g / m 2 to 50,000 g / m 2 per 24 hours, measured by the method described in Test methods for primary wound dressings Part 2 Moisture vapour transmission rate of permeable film dressings of BS EN 13726-2 2002. The backing layer 82 can be partially or fully transparent. The backing layer 82 can be a layer or film of polyurethane, such as Epurex 912T / 129 manufactured by Covestro, or Inspire 2350 manufactured by Coveris, or Medifilm 426 manufactured by Mylan.

[0063] As Figure 4 and 5AAs shown, in one embodiment, an adhesive layer 90, referred to as a backing layer adhesive 90, is disposed adjacent to the first surface 83 of the backing layer 82. The backing layer adhesive 90 includes a backing layer adhesive aperture 94 that preferably extends through the backing layer adhesive 90 from a first surface of the backing layer adhesive 90 to a second surface of the backing layer adhesive 90. The aperture 94 in the backing layer adhesive 90 is preferably positioned adjacent to the aperture 78 in the upper adhesive member 74. It should be appreciated that in the preferred embodiment, the flexible connector aperture 60, the upper absorbent indicator member 70, the upper adhesive aperture 78, the backing layer aperture 86, and the backing layer adhesive aperture 94 are all disposed substantially concentrically such that fluid flow can pass from the flexible connector aperture 60, through the upper absorbent indicator member 70, and through the upper adhesive aperture 78, the backing layer aperture 86, and the backing layer adhesive aperture 94. Further, it should also be appreciated that in the preferred embodiment, the upper flexible connector portion 67, the lower flexible connector portion 66, the upper absorbent indicator member 70, the upper adhesive 74, the backing layer 82, and the backing layer adhesive 90 are disposed in the wound exudate management system 10 in the order listed.

[0064] Referring to Figure 3A In some embodiments, the dressing 14 includes an inner envelope structure 100. The inner envelope structure 100 preferably houses multiple layers of absorbent material to aid in exudate management. As Figure 3A 、 4 As shown best in FIGS. 5A, in one embodiment, the inner envelope structure 100 is defined by an upper envelope layer and a lower envelope layer. The upper envelope layer can have a peripheral portion 108 and a central portion 109. The peripheral portion 108 of the upper envelope layer can also be referred to as an upper peripheral portion 108, and the central portion 109 of the upper envelope layer can also be referred to as an upper central portion 109. Similarly, the lower envelope layer can have a peripheral portion 116 and a central portion 117. The peripheral portion 116 of the lower envelope layer can be referred to as a lower peripheral portion 116, and the central portion 117 of the lower envelope layer can be referred to as a lower central portion 117.

[0065] Another alternative embodiment of the dressing 14 of the wound treatment system 10 is shown in Figure 3B and 5BIn this alternative embodiment, the nonwoven hydroentangled layer 119 is preferably stitched to the second surface 113 of the wound contact layer 112. In one embodiment, regenerated cellulose yarn is used for the stitching. Further, in one embodiment, the nonwoven hydroentangled web material 119 can be constructed from an 80 gsm nonwoven layer comprising substantially equal portions of viscose fibers and polyester fibers, preferably less than 5% of an acrylic copolymer adhesive. Further, a thermoplastic hydroentangled layer 121, such as a polyamide layer, can be disposed between the pressure distribution layer 104 and the plurality of absorbent material layers. The thermoplastic hydroentangled layer 121 has a first surface 123 that can be thermally bonded at its periphery to the pressure distribution layer 104 and a second surface 125 that can be similarly thermally bonded at its periphery to the nonwoven hydroentangled layer 119 around the plurality of absorbent material layers. Thus, the thermoplastic hydroentangled layer 121 and the nonwoven hydroentangled layer 119 form an inner perimeter enclosure or inner envelope around the absorbent material layers. The inner perimeter enclosure or inner envelope of this embodiment is defined by an upper envelope layer and a lower envelope layer. The upper envelope layer of this embodiment comprises the thermoplastic hydroentangled layer 121 and the lower envelope layer of this embodiment comprises the nonwoven hydroentangled web material 119.

[0066] Thus, in one embodiment, as shown in FIG. 1, the upper envelope layer is the pressure distribution layer 104 and the lower envelope layer is the wound contact layer 112. In another alternative embodiment, as shown in FIG. 2, the upper envelope layer is the thermoplastic hydroentangled layer 121 and the lower envelope layer is the nonwoven hydroentangled layer 119. Figure 3A Figure 3B Thus, in one embodiment, as shown in FIG. 1, the upper envelope layer is the pressure distribution layer 104 and the lower envelope layer is the wound contact layer 112. In another alternative embodiment, as shown in FIG. 2, the upper envelope layer is the thermoplastic hydroentangled layer 121 and the lower envelope layer is the nonwoven hydroentangled layer 119.

[0067] In some embodiments, the pressure distribution layer 104, also referred to as a pressure distribution layer, is used to distribute pressure or negative pressure laterally across the pressure distribution layer 104. The pressure distribution layer 104 can be gas, liquid, and vapor permeable and is used to help wicking into a greater portion of the dressing 14 by distributing negative pressure laterally across the dressing 14. In this manner, the absorption of exudate by the dressing 14 is maximized and a more uniform transfer of negative pressure to the wound or dressing 14 is optimized. The pressure distribution layer 104 can be formed from a foam, such as XD4200AS polyester foam manufactured by Caligen, another suitable reticulated foam, or a polyurethane foam.

[0068] ​In some embodiments, the wound contact layer 112 can be formed of an absorbent material. Further, the wound contact layer 112 can be composed of a structurally reinforced material or structure to enhance the strength and physical properties of the lower envelope layer 112. For example, the wound contact layer 112 can be formed of carboxymethylated cellulose fibers. The structurally reinforced material of the wound contact layer 112 can include a stitching 118. In some embodiments, the wound contact layer 112 is formed of an absorbent material having a reinforcing stitching 118, which includes a reinforcing stitching 118 made of nylon. It should also be understood that the pressure distribution layer 104 and the wound contact layer 112 can be formed of any of the absorbent materials described above.

[0069] The wound contact layer 112 has a first surface 114 and a second surface 113. In one embodiment, the first surface 114 of the wound contact layer 112 is an outer layer for contacting a user's wound when the dressing 14 is adhered to the user's skin adjacent to the wound. Further, in one embodiment, the second surface 113 of the wound contact layer 112 is opposite the first surface 114, and the second surface 113 is an inner layer that is adjacent to the plurality of absorbent material layers within the dressing 14, as described below.

[0070] The peripheral portion 108 of the upper envelope layer 104 (i.e., in one embodiment, the pressure distribution layer 104) and the peripheral portion 116 of the lower envelope layer 112 (i.e., in one embodiment, the wound contact layer 112) can be joined, as best shown in Figure 3A The upper peripheral portion 108 and the lower peripheral portion 116 can be joined by an adhesive, welding, stitching, or any other commonly used joining method. The joining of the upper peripheral portion 108 and the lower peripheral portion 116 substantially forms the inner envelope 100 and further defines an envelope cavity 120 disposed within the envelope 100.

[0071] In preferred embodiments, in some embodiments, the plurality of absorbent material layers 130a, 130b, 130c, 130d, 130e, 130f, 130g, 130h, etc. are disposed adjacent to one another and substantially within the envelope cavity 120. In one embodiment, there are eight layers of absorbent material within the envelope cavity 120. In some embodiments, the absorbent material layers 130a-h include gel-forming fibers such as those described above, and the gel-forming fibers can be sodium carboxymethyl cellulose fibers. Further, the absorbent material layers 130a-h can include any of the absorbent materials, water-swellable fibers, or gel-forming fibers as described above. For example, the absorbent material layers 130a-h can be formed of carboxymethylated cellulose fibers.

[0072] In some embodiments, one or more of the absorbent material layers 130a-h include one or more openings 129, such as Figure 5A As shown. The opening 129 can be a slit or opening 129 on the absorbent material layers 130a-h along one or more directions, preferably along a direction in plane with and transverse to the longitudinal axis of the absorbent material. This slit or opening 129 helps manage the flow of exudate through the individual layers 130a-h of the dressing 14. Specifically, the opening 129 promotes or allows wound exudate to travel or be absorbed in a preferred direction. In some embodiments, the opening 129 promotes or allows wound exudate to travel laterally around each layer of absorbent material, rather than axially from one layer to another. The opening 129 can be mechanically formed, for example by cutting. The opening 129 is preferably a slit about 10 mm in length, which can alternate vertically and horizontally through preferably each absorbent material layer in rows and columns. The opening is entirely used to fully utilize the absorbency of the absorbent material layers and can also help with negative pressure transmission through these layers.

[0073] In various embodiments, the dressing 14 includes an adhesive layer 150. The adhesive layer 150 helps to secure the dressing 14 to the patient's skin. In one embodiment, the adhesive layer 150 also helps to create a shell or outer enclosure with a backing layer 82, within which an inner enclosure 100 is located. Figure 3A As shown, in one embodiment, the adhesive layer 150 is attached to both the backing layer 82 and the wound contact layer 112. Specifically, in such an embodiment, the backing layer 82 is adhered radially outward from the inner portion of the adhesive layer 150 to the outer portion of the adhesive layer 150 to which the wound contact layer 112 is adhered. Figure 5A As best shown in one embodiment, the adhesive layer 150 has a peripheral shape with a central hole 154. When the dressing 14 is applied to the user's skin, the hole 154 in the adhesive layer 150 allows the user's skin to come into contact with or be in fluid communication with the wound contact layer 112.

[0074] like Figure 4 As best shown in one embodiment, the first surface 83 of the backing layer is preferably adjacent to and in contact with the pressure distribution layer 104 and the adhesive layer 150, while the flexible connector 50 is disposed on the second surface 84 of the backing layer.

[0075] The removable cover 156 can adhere to the outer surface of the adhesive layer 150. For example... Figure 3A and Figure 5AAs shown, in one embodiment, the removable cover 156 can be adhered to an outer surface of the adhesive layer 150 that is on an opposite side of the adhesive layer 150 from the wound contact layer 112 and the backing layer 82 to which the backing layer 82 is adhered. The removable cover 156, which can include multiple portions 156a, 156b having folded grip portions 158a, 158b, can be removed from the adhesive layer 150. Thus, in a preferred embodiment, when the removable cover 156 is adhered to the adhesive layer 150, the removable cover 156 protects the adhesive layer 150, but when the removable cover 156 is removed from the adhesive layer 150 to use the dressing 14, the outer surface of the adhesive layer 150 is exposed and the dressing 14 can be releasably secured to the skin of a user.

[0076] Turning to FIGS. Figure 7 and 8 The separable connector 44 is shown in detail in FIGS.

[0077] The distal connector portion 170 also preferably includes a first mating member, such as a thread, which can be a helical thread. A corresponding second mating member 184, such as a thread 184, can be provided in the proximal connector portion 188, such that the distal connector portion 170 can be releasably attached to the proximal connector portion 188 via engagement of the first mating member and the second mating member 184.

[0078] The combination of the inner splines 174 of the torque member 176 that are engageable with the corresponding distal splines 172 of the distal connector portion 170 enable a user to more easily manipulate and rotate the distal connector portion 170 relative to the proximal connector portion 188 to selectively attach the distal connector portion 170 to the proximal connector portion 188 and detach the distal connector portion 188 from the proximal connector portion 188. Figure 7 The distal connector portion 170 and the proximal connector portion 188 are shown in an attached state, Figure 8 The distal connector portion 170 and the proximal connector portion 188 are shown in a detached state.

[0079] As Figure 7 and 8As shown, in one embodiment, the proximal connection portion 188 is connected to and in fluid communication with an interface tube 194 that is disposed generally between the proximal connection portion 188 and the flexible connector 50. It should be appreciated that the distal conduit 40, the distal connection portion 170, the proximal connection portion 188, the interface conduit 194, and the flexible connector 50 are all in fluid communication with one another along the tube 22, thus enabling fluid communication between the pump 18 and the dressing 14.

[0080] In preferred embodiments, the proximal connection portion 188 includes a one-way valve 198. The one-way valve 198 allows fluid to travel through the one-way valve 198 in a first direction while generally or completely preventing fluid from traveling through the one-way valve 198 in a second direction. As an example, the one-way valve 198 allows fluid to flow through the proximal connection portion 188 toward the pump 18 and away from the dressing 14 while preventing fluid from flowing away from the pump 18 toward the dressing 14. This configuration enables the dressing 14 to continue to experience or exhibit negative pressure when the distal connection portion 170 and the proximal connection portion 188 are releasably separated, as described above. Figure 8 As shown, this increases user comfort, flexibility, and utility of the dressing 14 even when separated from the pump 18.

[0081] The wound exudate management system 10 preferably also includes an indicator system 200 that indicates that the fluid handling capacity of the dressing 14 has been or will soon be reached and that the dressing 14 should be replaced to avoid leakage of exudate from the dressing 14 or into the pump 18. The indicator system 200 can produce a signal, such as a visual signal, an audible signal, a vibratory signal, or the like. As an example, the indicator system 200 includes one or more of a gelling absorbent disposed within one or more of the upper absorbent indicator member 70, the backing layer 82, the pressure distribution layer 104, the wound contact layer 112, the absorbent material layers 130a-h, or the flexible connector 50. The gelling absorbent can include the absorbent material described above. The indicator system 200 can visually indicate that exudate has been absorbed by forming a gel. The indicator system 200 can also visually indicate that exudate has been absorbed due to a color change due to the wound exudate contacting some component or material within the dressing due to the exudate entering the indicator due to a change in color due to a mold activated by the exudate or other liquid, or by other means.

[0082] In some embodiments, the wound exudate management system 10, and in particular the dressing 14, can be provided in a variety of states. For example, the dressing 14 can be in a first state in which the dressing 14 is substantially free of exudate and fluid. The first state can correspond to fibers in the absorbent material of the dressing 14 having a first volume or size. Additionally, the first state channels between the fibers have a first volume. The dressing 14 can also be in a second state in which the fibers in the absorbent material of the dressing 14 have absorbed and are partially or fully saturated with exudate. The first state can correspond to fibers in the absorbent material of the dressing 14 having a second volume or size. The first volume or size is relatively smaller than the second volume or size. Thus, the channels or openings between the fibers are relatively larger. Similarly, in the second state, the volume or size of the channels between the fibers is reduced after the fibers have swelled upon contact with the wound exudate, and the channels or openings between the fibers are relatively small, or the fibers close the channels or openings. Upon continued application of negative pressure, the exudate is drawn through the saturated fibers of the absorbent material to the indicator system 200.

[0083] In other words, Figure 1 A wound dressing is shown that includes an outer cover layer and a conduit or tube that completely covers the other layers of the dressing. Under the cover layer is an absorbent pad that forms a central raised island under the cover layer. In one embodiment, the absorbent pad includes a plurality of layers of absorbent material.

[0084] The absorbent layer is capable of absorbing exudate from a wound. The outer cover layer covers the side of the absorbent layer furthest from the wound, as Figure 3A 、 4 and 5A, the cover layer, also referred to as a backing layer, is adapted to enable the application of negative pressure to the wound and has a port in fluid communication with the absorbent layer. A conduit or tube allows fluid communication between the port and a source of negative pressure, the conduit being attached to the outer layer by an adhesive ring. An indicator device or upper absorbent indicator member is disposed in the port. In one embodiment, the indicator device includes a layer of gel-forming fibers. Alternatively, the indicator device can also be disposed in the port but above the cover layer. The dressing also includes a wound contact layer adhered to the absorbent layer by a heat sealable tie layer comprised of a polyamide tie layer. The dressing also includes an exudate and pressure distribution layer, also referred to as a pressure distribution layer, which is preferably a polyester foam, which serves to diffuse exudate through the absorbent layer and to even out the negative pressure across the dressing. An additional heat sealable tie layer can be provided between the distribution layer and the cover layer. The heat sealable layers help to bond the layers together. The absorbent layer, the wound contact layer and the indicator device include a layer or layers of gel-forming fibers in the form of carboxymethylated cellulose fabric.

[0085] In one embodiment, the area of the absorbent layer is less than the area of the cover layer, asFigure 5A The cover layer is shown with a frame such that it forms an island within the frame of the cover layer. A silicone adhesive can be applied to the frame on the wound-facing side of the cover layer to seal the dressing to the skin around the wound. Alternatively, the dressing can be secured to the wound through a perforated adhesive that covers the wound-facing surface of the dressing with or without a window on the adhesive pad and / or through a dressing strip applied to the outer surface of the cover layer and the skin around the dressing.

[0086] In use, the dressing can be secured to the skin around the wound and a catheter connected to a source of negative pressure at the distal end of the catheter through a connector. Negative pressure is applied to the wound by applying negative pressure through the passageway for fluid to travel from the wound through the absorbent layer, the port, and to the distal end of the catheter. Exudate is absorbed by the wound contact layer and is transferred through intimate contact to the absorbent layer. The fenestrations that can be present in the absorbent layer aid in the absorption of exudate and the application of negative pressure. As exudate is absorbed by the absorbent layer, it spreads underneath the distribution layer such that a greater area of the absorbent layer is accessible to exudate and a greater capacity of the absorbent layer is used. Once the absorption capacity of the absorbent layer is reached, exudate spreads to the port and is absorbed by the gelled indicator device. The formation of the gel and possible color change of the indicator device is visible to the user of the dressing and indicates that the dressing needs to be changed. The indicator device can also or instead be present in the catheter or lock thereof, where the indicator device can also be seen by the user and can provide additional dressing change time before exudate is drawn into the pump or other source of negative pressure.

[0087] While some embodiments have been illustrated, discussed and described, numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the disclosure. Additionally, the present disclosure provides a sign base and sign assembly having increased structural strength, improved aesthetic design, packaging that facilitates flexible placement of the sign base, and wheel structure that allows for easy sign assembly shipping.

[0088] The disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those inherent therein. The particular implementations disclosed above are illustrative only of the teaching of the present disclosure and are not meant to limit or restrict the scope of the disclosure in any way rather, the scope of the disclosure encompasses any variations and modifications of the examples taught and adopted by one skilled in the art using no more than routine experimentation based on the teachings herein. Furthermore, unless specifically stated otherwise, terms used herein are not limited to the common meanings. To the extent that a term used in a claim is not defined herein, such term is intended to adopt its common meaning known in the art. It will be appreciated that details of the foregoing embodiments, although provided for illustration, should not be construed as limiting the scope of the disclosure. It should be apparent that aspects of the disclosure can be embodied in a wide variety of forms and that the disclosure can be placed into a considerable number of different configurations. Also, it will be appreciated that various components described herein can be rearranged or supplemented. Furthermore, any expression of a quantity of an element in the disclosure should not be construed as an admission that the quantity is essential, even if the element is essential. In addition, use of the alternative (e.g., "or", "either") should not be construed as an "exclusive or" unless expressly indicated. Also, the use of "a" or "an" should not be construed as "one", even if the only possible embodiment is "one", unless expressly so defined. Also, the use of "about" or "approximately" in connection with a value means that the exact value is not essential, even if the value is essential, and that slight variations are intended. Furthermore, the use of the term "if" has the same meaning as "when", even if the term "if" is used in connection with an event that will occur or has occurred. Furthermore, the use of the term "and" means "and / or" unless expressly indicated otherwise. Furthermore, the use of the term "or" means "and / or" unless expressly indicated otherwise. Furthermore, the use of the term "comprise", "comprises", "comprising" or "comprises" means "including, but not limited to" unless expressly indicated otherwise. Furthermore, the use of the term "based on" means "based, at least in part, on" unless expressly indicated otherwise.

[0089] As used herein, the phrase "at least one of," followed by a listing of items, and the term "and / or" are intended to mean one or more of the listed items, and that the integrity of the listing is not to be construed as requiring each and every one of the items to be present in the composition or process. The phrase "at least one of," followed by a listing of items, and the term "and / or" have the same meaning. Furthermore, unless specifically stated otherwise, terms used herein are not limited to the commonly understood meanings. To the extent that a term used in a claim is not defined herein, such term is intended to adopt its common meaning known to one skilled in the art. It will be appreciated that the foregoing description is by way of example only, and is not intended to limit the scope of the disclosure.

Claims

1. A negative pressure wound dressing for covering and protecting a wound, the wound dressing comprising: a wound contact layer having a first surface, a second surface, a peripheral region and a central region, wherein the first surface of the wound contact layer contacts the wound when the dressing is adhered to skin in the vicinity of the wound; a pressure distribution layer between an outer cover layer and a multi-layer absorbent material, wherein the pressure distribution layer is arranged to distribute negative pressure laterally across the pressure distribution layer, wherein the pressure distribution layer is permeable to gas, liquid and moisture vapor and has a peripheral region and a central region, and wherein the multi-layer absorbent material is disposed between the second surface of the wound contact layer and the pressure distribution layer; and an envelope formed by joining the peripheral region of the pressure distribution layer with the peripheral region of the second surface of the wound contact layer, wherein the multi-layer absorbent material is substantially disposed within an internal cavity of the envelope, wherein the pressure distribution layer is formed from a foam.

2. The wound dressing of claim 1, further comprising a thermoplastic hydroentangled layer joined to the pressure distribution layer and a nonwoven hydroentangled layer joined to the wound contact layer, and wherein the envelope is formed by joining peripheral portions of the nonwoven hydroentangled layer and the thermoplastic hydroentangled layer such that the multi-layer absorbent material is substantially disposed in the internal cavity of the envelope.

3. The wound dressing of claim 1, wherein, The multi-layer absorbent material comprises carboxymethylated cellulose fibers.

4. The wound dressing of claim 1, wherein, The wound contact layer comprises carboxymethylated cellulose fibers.

5. The wound dressing of claim 1, wherein, The pressure distribution layer is formed from a polyester foam, reticulated foam, or polyurethane foam.

6. The wound dressing of claim 1, wherein, The multi-layer absorbent material includes windows.

7. The wound dressing of claim 1, further comprising an upper absorbent indicator member formed from an absorbent material, wherein the upper absorbent indicator member is provided by gel-forming fibers, and wherein the upper absorbent indicator member is located in a port in the outer cover layer.

8. A negative pressure wound dressing for applying negative pressure to a wound, the wound dressing comprising: an absorbent layer capable of absorbing exudate from a wound and allowing fluid to pass through the absorbent layer; an outer cover layer covering a side of the absorbent layer furthest from the wound, the outer cover layer adapted to enable negative pressure to be applied at the wound and having a port; a conduit having a distal end and a proximal end attached to the port, wherein the wound dressing provides a passageway for fluid from the wound, through the absorbent layer and the port and to the distal end of the conduit; and an indicator located in the passageway at a location between the absorbent layer and the distal end of the conduit, wherein the indicator is capable of absorbing exudate to indicate the presence of exudate on a side of the absorbent layer furthest from the wound.

9. A wound exudate management system comprising: a pump for generating negative pressure; a dressing for covering and protecting a wound, the dressing comprising a wound contact layer, a backing layer, a pressure distribution layer in contact with the backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer, wherein the dressing comprises an envelope structure formed by a joining of peripheral portions of the pressure distribution layer and the wound contact layer. a tube connecting the pump and the dressing, the tube having a lumen for fluid communication between the pump and the dressing through the lumen; a one-way valve in series between the pump and the dressing to maintain negative pressure in the dressing when the pump is disconnected from the tube; and an indicator member positioned between the backing layer and the pump.

10. The wound exudate management system of claim 9, wherein, The at least one layer of absorbent material is disposed within the enclosure structure.

11. The wound exudate management system of claim 9, wherein, The indicator member is capable of absorbing exudate.

12. The wound exudate management system of any one of claims 9 to 11, wherein, The indicator member includes gel-forming fibers.

13. A wound exudate management system, comprising: a pump for generating negative pressure; a dressing for covering and protecting a wound, the dressing including a wound contact layer, a backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer; a tube connecting the pump and the dressing, the tube having a lumen for fluid communication between the pump and the dressing through the lumen; and a one-way valve in series between the pump and the dressing to maintain negative pressure in the dressing when the pump is disconnected from the tube; The at least one layer of absorbent material includes one or more windows.

14. The wound exudate management system of claim 13, wherein, The one-way valve is connected to one of the pump and the tube.

15. A wound exudate management system, comprising: a pump capable of generating negative pressure; a dressing for covering and protecting a wound, the dressing including a wound contact layer, a backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer; a flexible connector secured to and in contact with the backing layer and having a lumen; a tube positioned between the flexible connector and the pump, wherein the tube includes a lumen in fluid communication with the lumen of the flexible connector so as to connect the pump and the dressing; and a one-way valve in series between the pump and the dressing to maintain negative pressure in the dressing when the pump is disconnected from the tube. The dressing includes an enclosure structure formed by a combination of a perimeter portion of a pressure distribution layer and a second surface of the wound contact layer, and wherein the at least one layer of absorbent material is disposed within the enclosure structure.

16. The wound exudate management system of claim 15, wherein, 17. The wound exudate management system of claim 16, further comprising an indicator positioned between the at least one layer of absorbent material and the pump and configured to provide a visual indication of the presence of exudate.

18. The wound exudate management system of claim 17, further comprising an adhesive layer coupled to the flexible connector and the indicator. The adhesive layer is formed to include an aperture positioned proximate the indicator.

19. The wound exudate management system of claim 18, wherein, The backing layer is formed to include an aperture arranged substantially concentrically with the aperture of the adhesive layer.

20. The wound exudate management system of claim 19, wherein, The flexible connector is formed to include an aperture arranged substantially concentrically with the aperture of the adhesive layer and the aperture of the backing layer and is configured so as to allow fluid communication between the dressing and the lumen of the flexible connector.

21. The wound exudate management system of Claim 20, wherein, 22. A wound exudate management system, comprising: a pump for generating negative pressure; a dressing for covering and protecting a wound, the dressing including a wound contact layer, a backing layer, and at least one layer of absorbent material between the wound contact layer and the backing layer; a flexible connector secured to and in contact with the backing layer and having a lumen; a tube positioned between the flexible connector and the pump, wherein the tube includes a lumen in fluid communication with the lumen of the flexible connector so as to connect the pump and the dressing; and a one-way valve in series between the pump and the dressing to maintain negative pressure in the dressing when the pump is disconnected from the tube. A dressing for covering and protecting a wound, the dressing comprising a wound contact layer, a backing layer having an aperture formed therein, and at least one layer of absorbent material positioned between the wound contact layer and the backing layer; a flexible connector secured to and in contact with the backing layer of the dressing and having an internal lumen; a tube positioned between the flexible connector and the pump, wherein the tube has an internal lumen in fluid communication with the internal lumen of the flexible connector so as to connect the pump with the dressing; a one-way valve in series between the pump and the dressing to maintain negative pressure within the dressing when the pump is disconnected from the tube; and an indicator positioned between the at least one layer of absorbent material and the pump and configured to provide a visual indication of the presence of exudate, wherein the indicator is aligned with the aperture formed in the backing layer. The dressing comprises an enclosure structure formed by the combination of a pressure distribution layer and a peripheral portion of a second surface of the wound contact layer, and wherein the at least one layer of absorbent material is disposed within the enclosure structure.

23. The wound exudate management system of claim 22, wherein, At least one of the backing layer and the flexible connector is transparent so as to allow the indicator to be seen by a user of the wound exudate management system.

24. The wound exudate management system of Claim 22, wherein, ​

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