Patent Description:
Health care professionals (HCPs) are required to evaluate and treat a variety of wounds with different requirements which can change as treatment progresses. Accordingly, HCPs keep stocks of different types of dressings for different requirements.

Pressure gradient wound therapy (positive or negative) is one known way of treating various wound types. Typically, this involves applying a pressure differential between a sealed region of a wound dressing and te surrounding environment to assist with healing the wound, e.g. through removal of oedema, increasing blood flow, mechanical contraction of the wound, increasing formation of granulation tissue and/or active removal of excess exudate from the wound. Wound therapy of this type is particularly effective for the treatment of open traumatic, non-traumatic and chronic wounds.

Amongst different types of dressings are those designed and intended for use as an advanced wound dressing to manage exudate and protect th wound. These can, for example, have a wound contact layer including gelling fibres, such as the Hydrofiber (RTM) technology included in Aquacel (RTM) surgical dressings available from ConvaTec Ltd of Deeside, UK, which transform into a gel on contact with wound fluid. (Such wound dressings are not intended for use with pressure gradient wound therapy, nor used for such applications in practice, owing to their construction.

Other types of wound dressing are specially adapted to be used in conjunction with a pressure gradient wound therapy apparatus, e.g. with a negative pressure wound therapy (NPWT pump). In their original incarnation, NWPT systems had large, heavy (not portable/wearable) pump arrangements connected via tubing to the wound; at the wound, a reticulated open cell foam dressing is introduced into the wound and a separate adhesive drape is placed over the top. To connect the tubing to the wound in these large systems, a health care professional pinches the drape and foam beneath, and snips a hole through both drape and foam to form an aperture in the top for connection to the tubing. These systems and the two-part wound dressing (i.e. separate foam and drape) are still widely used in hospitals where professional staff are on-hand to set up te systems.

More recently, and especially in portable or wearable pressure gradient wound therapy systems intended for home-use, one-piece dressings have been introduced, in which an adhesive covering layer and dressing are integrated. An example of such a dressing is the Avelle (RTM) dressing available from ConvaTec Limited of Deeside UK. That dressing has a covering film layer with an adhesive border provided around its periphery to form a seal around the wound and a wound contact layer of stitch-bonded Hydrofiber (RTM) material. A foam pressure-distribution layer is provided between the covering layer and the wound contact layer (adjacent the covering layer) and additional layers of fenestrated Hydrofiber (RTM) layers are provided between the wound contact layer and the pressure-distribution layer. The covering layer is provided with an aperture, to allow connection of tubing from the negative pressure source and in this example, the dressing includes an "airway" extending from the aperture to a connector for connection to tubing through which negative pressure is provided.

Naturally, where a hospital or the like provides both "normal" wound dressings and those for use with pressure gradient wound therapy it needs to keep stocks of both, in various different sizes, which requires space, and lends complexity to the stock-ordering and stock selection process.

The present inventors have identified that it would be beneficial to be able to use a dressing for both pressure gradient wound therapy and "normal" treatment of wounds without a pressure gradient, in order that such treatment could be applied as and when required, and if no longer required, the dressings could still be used.

It is an aim of an embodiment or embodiments of the invention to overcome or at least partially mitigate one or more problems with the prior art and/or to provide an improved wound dressing. <CIT> describes a wound cover connecting device. <CIT> describes a wound therapy device. <CIT> describes a Negative Pressure Wound Therapy (NPWT) dressing having a sealing layer on a non-wound interfacing surface. <CIT> describes systems and methods for treating a tissue site with reduced pressure involving a reduced-pressure interface having a cutting element. <CIT>describes an apparatus and method for providing a fluid communication path to a wound site through a drape. <CIT> describes a negative pressure appliance and methods of using the same in the treatment of wounds. <CIT> describes a highly conformable wound dressing.

According to a first aspect of the invention there is provided a port for connecting a non-atmospheric pressure source to a wound dressing, the port comprising: a first aperture configured to connect to the non-atmospheric pressure source; a wound dressing contact surface; the wound dressing contact surface comprising a second aperture in fluid communication with the first aperture and configured to allow fluid communication with the wound dressing; and a piercing means configured to pierce the wound dressing as the wound dressing contact surface of the port is applied to the wound dressing, wherein the port further comprises a housing, wherein the piercing means is configured to extend from the housing, and to be retractable into the housing.

Advantageously, providing a port with a piercing means configured to pierce wound dressing (in particular a covering layer of the wound dressing) as the port is applied, can produce an aperture in the wound dressing which makes it possible to change the configuration of a wound dressing. Accordingly, a wound dressing which is normally sealed, e.g. by a closed, sealed and/or uninterrupted cover layer and thereby (only) suitable for use without a pressure gradient wound therapy system can be reconfigured, by introducing an aperture therein so as to configure the wound dressing for use in a pressure gradient wound therapy system (in which non-atmospheric pressure, e.g. negative pressure, can be applied through the aperture).

By allowing the reconfiguration of wound dressings, stock-keeping is simplified. Moreover, if, during "normal" treatment without pressure gradient it is determined that it would be beneficial for pressure gradient wound therapy to be used, such a system could be added, by configuring the wound dressing accordingly, i.e. piercing the dressing with the port to provide an aperture and attaching a source of non-atmospheric pressure (e.g. tubing from a NWPT pump) to the port. Notably, this could be done without the need for an additional dressing change, thus reducing the risk of wound infection. Similarly, if a wound is being treated with a pressure gradient, e.g. NWPT and the amount of exudate produced is reduced, so that NWPT is no longer required, a patient would be able to use up the stock of dressings without the NWPT system, by configuring them for use without the system (i.e. by not attaching the port which forms an aperture in them).

The port may be provided in a kit of parts. The kit may be for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system. The kit may be packaged. The kit may comprise at least one of: a) packaging indicating that the port is configured to pierce a wound dressing (in particular a covering layer thereof) to produce an aperture therein and thereby configure the wound dressing for use in a pressure gradient wound therapy; (b) instructions instructing a user as to how to use the port to configure a wound dressing for use in a pressure gradient wound therapy system; (c) one or more selectively configurable wound dressings, the wound dressings being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; (d) a source of non-atmospheric pressure; or (e) tubing for connection between a wound dressing and a source of non-atmospheric pressure; the kit being arranged within a sealed package.

Providing a port along with one or more other items necessary to understand its function is also advantageous. For example, by including the packaging/instructions of (a) or (b)) a user can understand how to use the port in accordance with the invention; by including the dressings of (c) with which it is to be used, a user has all that is necessary to configure the dressings as desired; and by including one or more of the parts of a pressure gradient wound therapy apparatus (e.g. the source of non-atmospheric pressure (d) or tubing (e), the user will have the parts necessary to set up the apparatus, and reconfigure dressings (which may of course have been obtained separately) for use with the pressure gradient wound therapy apparatus.

When used herein and throughout the specification the term "pressure gradient wound therapy apparatus" is intended to cover a wound therapy apparatus wherein a pressure differential (either positive or negative) is applied between a sealed region of the wound dressing and the surrounding environment.

As used herein, negative pressure wound therapy is a therapeutic technique using a suction dressing to remove excess exudation and promote healing in acute or chronic wounds. A vacuum of -<NUM> to -<NUM> Hg, or -<NUM> to -<NUM> Hg may be applied with typical negative pressure of -<NUM> to -<NUM> Hg, -<NUM> to -<NUM> Hg, or often about -<NUM> Hg being applied to a wound.

For positive pressure wound therapy, a net positive pressure is applied to the wound, which may include providing simultaneous aspiration and irrigation of the wound. Positive pressure wound therapy may be carried out at a positive pressure of up to <NUM>% atm. , typically at a low positive pressure of up to <NUM>% atm. , more usually up to <NUM>% atm. at the wound. Positive pressure wound therapy is known and referred to in <CIT>.

Optional features set out below may apply to any aspect of the invention.

The port may be provided in a sterile package. The sealed package in which the kit is arranged may be sterile.

The piercing means may comprise a cutting edge. The piercing means may comprise a blade having a cutting edge. The piercing means may comprise a cutting point. The piercing means may comprise a spike having a cutting point. The piercing means may comprise a plurality of cutting edges or cutting points.

The piercing means may have a curved cutting edge. This may be advantageous in terms of cutting a circular aperture, well suited for attachment to a source of negative pressure.

The piercing means may have a circular cutting edge. This allows a circular aperture to be cut into the wound dressing.

The piercing means may have a part-circular cutting edge. The part circular cutting edge may be at least <NUM> degrees; at least <NUM> degrees, or at least <NUM> degrees of a circle. A part circular cutting edge of such a size can cut a door into the covering layer of the wound dressing. The part circular cutting edge, may, on the other hand, be no more than <NUM> degrees; no more than <NUM> degrees or no more than <NUM> degrees of a circle. A part circular edge of such a size can be twisted to cut a door in the covering layer, or to cut a chad out of the covering layer.

The piercing means may be biased towards a retracted position. The bias may be a spring-bias. The piercing means may be spring-loaded. Alternatively, the piercing means may be movable to the retracted position when negative pressure is applied to the first aperture in the port.

The port may comprise an actuator. Actuation of the actuator may move the piercing means to an extended position. The actuator may comprise a button.

The piercing means may be arranged to extend a predetermined extended distance from a base of the port, e.g. from a base of the housing (i.e. to be fixed extending a predetermined extended distance, or to be moveable to a predetermined extended distance in the extended position). This can ensure that the cutting edge or cutting point is able to cut right through a covering layer of a wound dressing, in order that fluid can pass through the aperture cut into the covering layer, whilst not cutting too deeply into the body of the dressing, so as to reduce damage to internal parts of the dressing, such as a pressure distribution layer, or an absorbent layer. For example, where the port is for use in a dressing with a pressure distribution layer sandwiched between a covering layer and an absorbent layer, the cutting edge or cutting point can be arranged to extend through the covering layer, to extend into the pressure distribution layer and not to extend into the absorbent layer.

The predetermined extended distance may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, such as between <NUM> and <NUM>, for example about <NUM>.

The cutting edge or cutting point may be arranged to retract a predetermined retracted distance into the housing in the retracted position. This can ensure that in the retracted position (to which the cutting edge is preferably biased) it is sufficiently far into the housing as to reduce the likelihood of any accidental injuries. The predetermined retracted distance may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, between <NUM> and <NUM>, for example about <NUM>.

Balancing the distance by which the cutting point or cutting edge extends against the distance by which it retracts, can produce a port that is perfectly suited to its purpose.

The wound dressing contact surface may comprise a base. The base may be rigid. The base may be provided with an adhesive underside for connection to the dressing. The base may comprise the second aperture. The piercing means may extend beyond the underside of the base. The piercing means may be arranged to extend through an aperture in the base.

The port may comprise a connector part comprising the first aperture configured to connect to the non-atmospheric pressure source and a base plate comprising the wound dressing contact surface. The connector part and the base plate may be separable. The piercing means may be provided on the connector part. The piercing means on the connector part may be configured to extend through the aperture in the base plate.

The housing may comprise the base. The first aperture may be arranged orthogonal to the second aperture. The base may be annular.

As noted above, the optional features set out above are equally applicable to all aspects (or embodiments) of the invention (including those set out below).

According to a second aspect of the present invention, there is provided a kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising a port according to the first aspect and at least one of: a) packaging indicating that the port is configured to pierce a wound to produce an aperture therein and thereby configure the wound dressing for use in a pressure gradient wound therapy; (b) instructions instructing a user as to how to use the port to configure a wound dressing for use in a pressure gradient wound therapy system; (c) one or more selectively configurable wound dressings, the wound dressings (<NUM>) being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; (d) a source of non-atmospheric pressure; or (e) tubing for connection between a wound dressing and a source of non-atmospheric pressure; the kit being arranged within a sealed package.

According to an one embodiment of the invention there is provided a packaged kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising: a port according to the first aspect; and at least a) packaging indicating that the port is configured to pierce a covering layer of a wound dressing to produce an aperture therein and thereby configure the wound dressing for use in a pressure gradient wound therapy; the kit being arranged within a sealed package.

According to an one embodiment of the invention there is provided a packaged kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising: a port according to the first aspect; and at least (b) instructions instructing a user as to how to use the port to configure a wound dressing for use in a pressure gradient wound therapy system; the kit being arranged within a sealed package.

According to an one embodiment of the invention there is provided a packaged kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising: a port according to the first aspect; and at least (c) one or more selectively configurable wound dressings, the wound dressings being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit being arranged within a sealed package.

The dressing preferably comprises a covering layer and at least two further layers, a first layer adjacent the covering layer and a second layer separated from the covering layer by the first layer, and the cutting edge is preferably arranged to extend through the covering layer, to extend into the first layer and not to extend into the second layer. For example, a pressure distribution layer may be sandwiched between a covering layer and an absorbent layer, and the cutting edge is preferably arranged to extend through the covering layer, to extend into the pressure distribution layer and not to extend into the absorbent layer. The dressing preferably is a one-piece dressing, wherein the covering layer and at least the first and second layers of the wound dressing are provided as an integral item. The one-piece dressing is preferably provided in a sterile sealed package.

According to an one embodiment of the invention there is provided a packaged kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising: a port according to the first aspect; and at least (d) a source of non-atmospheric pressure; the kit being arranged within a sealed package.

According to an one embodiment of the invention there is provided a packaged kit of parts for use with a selectively configurable wound dressing, the wound dressing being configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system; the kit comprising: a port according to the first aspect; and at least (e) tubing for connection between a wound dressing and a source of non-atmospheric pressure; the kit being arranged within a sealed package.

Of course the kit may comprise various combinations of features a to e; for example the kit may comprise at least two features including a+b; the kit may comprise at least two features including a+c; the kit may comprise at least two features including a+d; the kit may comprise at least two features including a+e;; the kit may comprise at least two features including b+c; the kit may comprise at least two features including b+d; the kit may comprise at least two features including b+e; the kit may comprise at least two features including c+d; the kit may comprise at least two features including c+e; the kit may comprise at least two features including d+e. The kit may comprise at least three features including a+b+c; the kit may comprise at least three features including a+b+d; the kit may comprise at least three features including a+b+e; the kit may comprise at least three features including a+c+d; the kit may comprise at least three features including a+c+e; the kit may comprise at least three features including a+d+e; the kit may comprise at least three features including b+c+d; the kit may comprise at least three features including b+c+e; the kit may comprise at least three features including b+d+e; or the kit may comprise at least three features including c+d+e. The kit may comprise at least four features including a+b+c+d; the kit may comprise at least four features including a+b+c+e; the kit may comprise at least four features including b+c+d+e;. The kit may comprise all five features including a+b+c+d+e.

One particular embodiment includes at least one item selected from a+b; one particular embodiment includes at least one item selected from a+c; one particular embodiment includes at least one item selected from a+d; one particular embodiment includes at least one item selected from a+e; one particular embodiment includes at least one item selected from b+c; one particular embodiment includes at least one item selected from b+d; one particular embodiment includes at least one item selected from b+e; one particular embodiment includes at least one item selected from c+d; one particular embodiment includes at least one item selected from c+e; one particular embodiment includes at least one item selected from d+e; one particular embodiment includes at least one item selected from a+b+c; one particular embodiment includes at least one item selected from a+b+d; one particular embodiment includes at least one item selected from a+b+e; one particular embodiment includes at least one item selected from a+c+d; one particular embodiment includes at least one item selected from a+c+e; one particular embodiment includes at least one item selected from a+d+e; one particular embodiment includes at least one item selected from b+c+d; one particular embodiment includes at least one item selected from b+c+e; one particular embodiment includes at least one item selected from b+d+e; one particular embodiment includes at least one item selected from c+d+e; one particular embodiment includes at least one item selected from a+b+c+d; one particular embodiment includes at least one item selected from a+b+c+e one particular embodiment includes at least one item selected from b+c+d+e.

The packaging may for example be cardboard packaging. The packaging may comprise printed information indicating that the wound dressing is selectively configurable for use in a pressure gradient wound therapy system and without a pressure gradient wound therapy system. The packaging may be sterile; and/or at least part of the packaging, or a sub-package may be sterile.

The instructions instructing a user as to how to configure the wound dressing for use in a pressure gradient wound therapy system and for use without a pressure gradient wound therapy system may be printed on packaging. The instructions instructing a user as to how to configure the wound dressing for use in a pressure gradient wound therapy system and for use without a pressure gradient wound therapy system may be provided on an instruction sheet (which where the kit includes features a+b may be provided in the packaging).

The source of non-atmospheric pressure preferably a source of negative pressure. Alternatively it may be a source of positive pressure. The source of non-atmospheric pressure may be a pump.

The tubing for connection between a wound dressing and a source of non-atmospheric pressure may be transparent tubing. The tubing may be flexible. The tubing may be resilient. The tubing may be formed from a resilient flexible plastics material.

As for the wound dressing:
The wound dressing may comprise a covering layer. The wound dressing may comprise a pressure distribution layer. The covering layer may define a cavity. The pressure distribution layer may be provided in, e.g. contained in, the cavity. The covering layer may comprise an indica; the indica may denote a position (for example a suitable position or the optimal position) in the covering layer to create an aperture to provide fluid communication between the pressure distribution layer and a source of non-atmospheric pressure.

The shape of the indicia may match the shape of the piercing means. The shape of the indicia may match the shape of the cutting edge. The shape of the indicia may match the shape of the housing. The size of the indicia may match the size of the piercing means. The size of the indicia may match the size of the cutting edge. The size of the indicia may match the size of the housing. By matching the shape and/or size of the indicia to the shape and/or size of the piercing means, it is straightforward for the user to align the piercing means with the position denoted by the indicia where the wound dressing should be pierced to cut an aperture therein and thereby configure it for use in a pressure gradient wound therapy system.

In one embodiment the wound dressing may comprise a wound contact layer and a covering layer, the covering layer having a first surface facing the wound contact layer and defining a wound dressing cavity, and a second surface; wherein the second surface of the covering layer comprises an indica, the indica denoting a suitable, or more preferably an optimal, position in the covering layer to create an aperture to provide fluid communication between the wound dressing cavity and a source of non-atmospheric pressure.

In one embodiment the wound dressing may comprise a pressure distribution layer and a covering layer; wherein the covering layer comprises an indica, the indica denoting the optimal position in the covering layer to create an aperture to provide fluid communication between the pressure distribution layer and a source of non-atmospheric pressure.

The indicia may be a mark. The mark may be formed of ink or dye, for example the indicia may be printed. The mark may be formed by discoloration, e.g. the indicia could be laser marked. The indicia may be printed onto the covering layer. Alternatively the indicia could be applied by other means. The covering layer may have an upper side and an underside. The indicia may be applied onto the upper side of the covering layer. The indicia may be applied onto the underside of the covering layer. The covering layer may be transparent or translucent (this would allow indicia to be visible even if printed onto the underside).

The indicia is preferably located out of alignment (i.e. vertical alignment in use) with the centre of the dressing. For example it may be located towards the periphery of the covering layer and/or the pressure distribution layer (or the wound when in use). This assists in the spread of exudate across the full extent of the pressure distribution layer (and across an absorbent layer where an absorbent layer is provided).

The pressure distribution layer may be provided adjacent to the cover layer. The covering layer may define a cavity. The pressure distribution layer may be provided in, e.g. contained in, the cavity. The pressure distribution layer may be gas and liquid permeable and particularly moisture vapour permeable. The pressure distribution layer serves to aid access of exudate to a greater area of the absorbent layer by allowing it to spread under the distribution layer. The pressure distribution layer also serves to even out the negative pressure applied to the wound over the whole dressing (when used for NPWT). The pressure distribution layer is preferably configured to distribute exudate and negative pressure over the dressing. The pressure distribution layer is preferably a foam layer such as a polyester foam of the type XD4200AS manufactured by Caligen or another suitable reticulated foam.

An adhesive layer may be provided so as to form an adhesive border. The adhesive layer may be provided on the underside of the covering layer. The adhesive border may be provided at the periphery of the dressing arranged to adhere the dressing to the skin surrounding the wound to form a fluid tight seal. The adhesive layer may be provided with perforations to assist transport of exudate and fluid through the dressing. The adhesive layer may also be applied to any of the other layers to provide an island configuration.

The indicia may be located in a region of the covering layer within that defined by the adhesive border. For example it may be located towards the periphery of the region of the covering layer inwards of the adhesive border.

In the configuration for use without a pressure gradient wound therapy system the region of the covering layer within that defined by the adhesive border may be closed, sealed and/or uninterrupted, e.g. a continuous unbroken membrane. This restricts/prevents microbes, bacteria or the like from entering the wound dressing and hence from entering the wound. In the configuration for use with a pressure gradient wound therapy system the region of the covering layer within the adhesive border may be interrupted by an opening, the opening being an aperture in the region of the indicia for connection to a source of non-atmospheric pressure. This allows non-atmospheric pressure to be applied to the wound.

The wound dressing may include a dressing body comprising an absorbent material for contacting the wound, i.e. which may be positioned in contact with a wound, in use. The dressing body may be formed from one of more layers. The dressing body may be configured to absorb exudate from the wound, aided by the action of a connected pump assembly. The dressing body may comprise an absorbent foam material, for example a layer of absorbent foam material. The foam material may comprise a superabsorbent material, for example a superabsorbent foam material. The dressing body may be formed of a hydrocolloid material which may gel in the presence of an exudate. The hydrocolloid material may comprise a layer or multiple layers of gelling fibres and absorbent materials. The covering layer may be constructed of a thin film layer (e.g. a polyurethane) enabling moisture vapour to exit the dressing at an increased rate. This combination is particularly suitable for allowing the wound therapy apparatus to manage fluid without the need of a canister. This may be referred to as a "canister-less" or "canister-free" system. In a variant, the wound dressing may be operable to be fluidly connected to a canister into which exudate removed from the wound may be withdrawn. The adhesive border may define an interior region of the wound dressing. The dressing body may be provided in the interior region of the wound dressing.

The wound dressing may comprise a release layer, the release layer being removable to reveal the adhesive border.

The wound dressing may have a thickness between <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, for example.

The pressure distribution layer may be a foam layer. The wound dressing may comprise the outer cover layer, the pressure distribution layer, one or more absorbent layer(s) and a silicone gel wound contact layer. The wound dressing may comprise an outer cover layer and one or more absorbent layer(s) in combination with a gel-forming fibre. The gel-forming fibre typically is in direct contact with the wound, and thus no additional wound contact layer is required i.e., a silicone gel wound contact layer does not require a silicone gel layer.

Gel-forming fibres include hygroscopic fibres which upon the uptake of wound exudate become moist slippery or gelatinous. The gel forming fibres can be of the type which retain their structural integrity on absorption of exudate or can be of the type which lose their fibrous form and become an amorphous or structureless gel. The gel forming fibres are preferably sodium carboxymethylcellulose fibres, chemically modified cellulosic fibres, alkyl sulphonate modified cellulosic fibres such as those described in <CIT>, pectin fibres, alginate fibres, chitosan fibres, hyaluronic acid fibres, or other polysaccharide fibres or fibres derived from gums. The cellulosic fibres preferably have a degree of substitution of at least <NUM> carboxymethyl groups per glucose unit. The gel forming fibres preferably have an absorbency of at least <NUM> grams <NUM>% saline solution per gram of fibre (as measured by the free swell method).

The gel forming fibres are preferably chemically modified cellulosic fibres in the form of a fabric and in particular carboxymethylated cellulose fibres as described in <CIT> to Azko Nobel UK Ltd, and can be provided by a layer of gel forming fibres preferably located in a port of the cover layer or as a layer of fibres in a conduit of the wound dressing. When present in the conduit, the layer of fibres can also serve to keep the conduit open to the passage of fluid in the event that the conduit is kinked or otherwise restricted by being lain on or leaned on by the user. The carboxymethylated cellulosic fabrics preferably have a degree of substitution between <NUM> to <NUM> as measured by IR spectroscopy (as defined in <CIT>) more preferably a degree of substitution of between <NUM> and <NUM> and are made by carboxymethylating a woven or non-woven cellulosic fabric such that the absorbency is increased. Particular preferred fabrics have an absorbency of between <NUM>/g of sodium/calcium chloride as defined above to <NUM>/g of sodium/calcium chloride as measured by the method described in <NPL>", <NPL>". Particularly preferred fabrics have an absorbency of <NUM>/g to <NUM>/g and most preferred of <NUM>/g to <NUM>/g of sodium/calcium chloride as measured by the method defined above.

The cellulosic fabric preferably consists solely of cellulosic fibre but may contain a proportion of non-cellulosic textile fibre or gel forming fibre. The cellulosic fibre is of known kind and may comprise continuous filament yarn and/or staple fibre. The carboxymethylation is generally performed by contacting the fabric with an alkali and a carboxymethylating agent such a chloracetic acid in an aqueous system. The fabric is preferably of a non-woven type to reduce shedding in the wound on cutting the dressing. Preferably the fabric is hydroentangled and thus comprises a series of apertures on a microscopic scale.

Where present, the absorbent layer of the wound dressing is capable of absorbing exudate from the wound and allowing the passage of fluid through it. The absorbent layer can comprise any absorbent capable of absorbing exudate while allowing the passage of fluid through it, such as a foam, sponge or fibre-based material, preferably the absorbent layer is provided by gel forming fibres of the same type or of a different type as those discussed above. The gel-forming fibres are hygroscopic fibres which upon the uptake of wound exudate become moist slippery or gelatinous and thus reduce the tendency for the surrounding fibres to adhere to the wound. The gel forming fibres are preferably spun sodium carboxymethylcellulose fibres, chemically modified cellulosic fibres, alkyl sulphonate modified cellulosic fibres such as those described in <CIT>, pectin fibres, alginate fibres, chitosan fibres, hyaluronic acid fibres, or other polysaccharide fibres or fibres derived from gums. The cellulosic fibres preferably have a degree of substitution of at least <NUM> carboxymethyl groups per glucose unit and more preferably are lightly substituted so that the absorbency of the fibres is limited. The gel forming fibres preferably have an absorbency of at least <NUM> grams <NUM>% saline solution per gram of fibre (as measured by the method described above) but less than <NUM> grams <NUM>% saline solution per gram of fibre. The gel forming fibres are preferably carboxymethylated cellulose fibres as described in PCT <CIT> to Azko Nobel UK Ltd which describes lightly carboxymethylated cellulose fabrics. The gel forming fibres are preferably lightly carboxymethylated in order to reduce the tendency of the absorbent layer to gel block and block the pathway for fluid from the wound, e.g. through the absorbent layer, the port and to a distal end of the conduit.

Preferably an absorbent layer is provided with fenestrations to aid the application of negative pressure to the wound and maintain the pathway for fluid from the wound, through the absorbent layer. Typically, however, fenestrations are only provided in internal absorbent layers.

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(s). The wound contact layer may be capable of absorbing exudate from the wound and transmitting it to the absorbent layer. Thus, there may be provided "internal" absorbent layers as defined above, preferably including fenestrations and an external absorbent layer, which forms the wound contact layer. Like the internal absorbent layer, the wound contact layer may be capable of allowing the passage of fluid through it so that pressure (either positive or negative) may applied to the wound and the pathway for fluid/exudate from the wound to the distal end of the conduit may be maintained.

The wound contact layer may include gel-forming fibres (e.g. of the type discussed herein), or a silicone gel, for example.

Preferably the wound contact layer comprises gel-forming fibres. The gel-forming fibres may be the same or a similar type to those comprising the absorbent layer but the wound contact layer may be strengthened to increase its integrity and that of the dressing. For example, the wound contact layer may be of the type described in <CIT> and comprise gel-forming fibres in the form of a mat with lines of 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 the pathway for fluid/exudate from the wound to the distal end of the conduit.

Preferably the one or more absorbent layer(s) comprise an internal absorbent layer provided with fenestrations to aid the application of negative pressure to the wound and maintain the pathway for fluid from the wound, through the internal absorbent layer and a wound contact layer comprising gel-forming fibres is also provided.

The (outer) cover layer of the dressing is provided as a bacterial and viral barrier layer which preferably resists the ingress of liquid and air but allows moisture vapour transmission. In this way the cover layer enhances the overall fluid handling capacity of the dressing by allowing for the escape of moisture vapour through the cover while enabling the application of pressure (either positive or negative) to the wound. The outer cover layer is for instance a layer having a MVTR of at least <NUM>,<NUM> m-<NUM> per <NUM> hours or in the range of from <NUM>,000gm-<NUM> to <NUM>,<NUM> m-<NUM> per <NUM> hours measured by the method described in <NPL>". The cover layer may be in the form of a film of polyurethane, for example Epurex <NUM> T/<NUM> manufactured by Covestro or Inspire <NUM> manufactured by Coveris or Medifilm <NUM> manufactured by Mylan.

The wound dressing preferably is a one-piece dressing. That is to say, it is the covering layer and the body of the wound dressing are provided as an integral item, preferably including an adhesive layer and preferably including a removable release layer. The body of the wound dressing that is provided, along with the covering layer, as an integral item may comprise the pressure distribution layer.

The one-piece dressing may be provided in a package. The package may be a sterile package.

According to a third aspect of the invention there is provided a pressure gradient wound therapy apparatus, comprising the kit of the second aspect of the invention and including each of items (a) to (e).

In embodiments, the wound therapy apparatus comprises a negative pressure wound therapy apparatus. In other embodiments, the wound therapy apparatus comprises a positive pressure wound therapy apparatus.

In embodiments, the apparatus may comprise a canister and the wound dressing may be fluidly connected to the canister into which exudate removed from the wound may be withdrawn. In preferred embodiments, the wound dressing may be formed of a hydrocolloid material which may gel in the presence of an exudate and the apparatus may include no cannister. This may be referred to as a "canister-less" system.

The pump assembly may be fluidly connected to an interior region of the wound dressing, for introducing and/or removing gas from within the wound dressing to control the pressure therein.

The embodiments of <FIG>, <FIG> referred to below are not encompassed by the wording of the claims but are considered as useful for understanding the invention.

Embodiments disclosed herein relate to apparatus and methods of treating a wound both with and without reduced or positive pressure (typically negative pressure). Some embodiments including pump and wound dressing component. The wound dressings discussed are "one-piece" dressings incorporating both a covering layer and an absorbent body.

As disclosed herein the present invention may comprise a port; or a kit comprising the port and other apparatus for providing pressure gradient wound therapy to a wound.

As used herein the expression "wound" may include an injury to living tissue may be caused by a cut, blow, or other impact, typically one in which the skin is cut or broken. A wound may be a chronic or acute injury. Acute wounds occur as a result of surgery or trauma. They move through the stages of healing within a predicted timeframe. Chronic wounds typically begin as acute wounds. The acute wound can become a chronic wound when it does not follow the healing stages resulting in a lengthened recovery. It is believed that the transition from acute to chronic wound can be due to a patient being immuno compromised.

Chronic wounds may include for example: venous ulcers (such as those that occur in the legs), which account for the majority of chronic wounds and mostly affect the elderly, diabetic ulcers (for example, foot or ankle ulcers), peripheral arterial disease, pressure ulcers, or epidermolysis bullosa (EB).

Examples of other wounds include, but are not limited to, abdominal wounds or other large or incisional wounds (either as a result of surgery, trauma, stemiotomies, fasciotomies, or other conditions), dehisced wounds, acute wounds, chronic wounds, subacute and dehisced wounds, traumatic wounds (such as from orthopaedic trauma), flaps and skin grafts, lacerations, abrasions, contusions, burns, diabetic ulcers, pressure ulcers, stoma, surgical wounds, trauma and venous ulcers, broken bones or the like.

Wounds may also include a deep tissue injury. Deep tissue injury is a term proposed by the National Pressure Ulcer Advisory Panel (NPUAP) to describe a unique form of pressure ulcers. These ulcers have been described by clinicians for many years with terms such as purple pressure ulcers, ulcers that are likely to deteriorate and bruises on bony prominences.

The technology disclosed can be used on an acute or chronic wound.

Wounds are believed to be more susceptible to infection under the following circumstances. If the wounds are chronic wounds, or if an object which caused the wound was dirty or contained bacteria, or from a bite, or contains remnant or a whole object that caused the wound, or a wound that is large or deep, or jagged edges to the wound, or elderly, or chronic because by their nature a wound site is open; and/or if the patient has: diabetes type <NUM> or type <NUM>, is elderly, or has a compromised immune system.

Pressure gradient wound therapy may also be useful for treating second- and third-degree burns, as well as being useful for laparotomy surgery i.e., a large incision through an abdominal wall to gain access into the abdominal cavity.

<FIG> illustrates an embodiment of a wound dressing <NUM> for use in accordance with the invention in two different configurations.

In general, the invention relates to the port <NUM>/<NUM>/<NUM> (of <FIG> (which is an embodiment useful for understanding the invention), <FIG> (which is an embodiment useful for understanding the invention) and <FIG>) which is used in configuration of a wound dressing <NUM>, the wound dressing <NUM> being selectively configurable for use without a pressure gradient wound therapy system or for use with a pressure gradient wound therapy system, e.g. negative pressure wound therapy.

As shown in <FIG>, the wound dressing <NUM> includes an optional indicia <NUM> visible on the upper (outside) surface of a covering layer <NUM> of the dressing <NUM>. The covering layer <NUM> has a raised central region <NUM>, where it overlies a dressing body, which can include a pressure dispersion layer; an absorbent/superabsorbent layer/layers; and a wound-contact layer. The dressing <NUM> also has a border region <NUM>, where it overlies an adhesive layer. A removable release layer (not shown) is provided on the underside.

The indicia <NUM> is a marking which indicates where the dressing should be cut to form an aperture in order to configure the dressing for use with a pressure gradient wound therapy system; the dressing being configured for use without a pressure gradient wound therapy system unless/until an aperture is cut in the covering layer. In this embodiment, the indicia <NUM> is shown as a circle formed in dashed lines, arranged in the optimal position for connection of a source of non-atmospheric pressure. Obviously in other embodiments alternative shapes/signs could be used and of course the indicia need not be in dashed lines.

Moreover it is contemplated that the port <NUM>/<NUM>/<NUM> may be used with dressings not having an indicia at all, with the user following instructions, in order to pierce the covering layer in a suitable location (e.g. the region shown by reference numeral <NUM>).

As illustrated in <FIG>, the wound dressing <NUM> is configured for use without a pressure gradient wound therapy system. To use the wound dressing <NUM> without a pressure gradient wound therapy system, the release layer is simply removed and the dressing applied in the same way as an ordinary wound dressing. It will be noted that the entire raised central region <NUM> of the covering layer <NUM> is a continuous unbroken membrane, uninterrupted and closed, so that the wound (within the region defined by the adhesive border) is in a sealed environment, restricting/preventing bacteria/microbes entering the wound and causing infection.

<FIG> shows the wound dressing <NUM> of <FIG> configured for use with a pressure gradient wound therapy system. Here, a user has cut through the cover layer <NUM> using the port <NUM> in the region of the indicia <NUM>, to form an aperture <NUM> in the wound dressing <NUM> (so that the central region <NUM> is no longer closed/uninterrupted). With the wound dressing <NUM> now configured for use with a pressure gradient therapy system, a source of non-atmospheric, e.g. negative, pressure can be connected to the aperture <NUM> via the port <NUM>/<NUM>/<NUM> to aid the wound-healing process.

For example, the port <NUM>/<NUM>/<NUM> can be adhered to the wound dressing <NUM>, such that a conduit through the port is aligned with the aperture <NUM>; the port can be connected via tubing (not shown in <FIG>) to a pump (also not shown in <FIG>) producing negative pressure.

A first embodiment of a port <NUM> (which is an embodiment useful for understanding the invention) best seen in <FIG> is specially configured, not only to carry out its primary function associated with prior art ports (i.e. to connect the wound dressing to a source of negative pressure), but also to pierce the covering layer of a wound dressing, whilst not cutting too deeply into the dressing. The port <NUM> may be provided in a sterile package and as part of a kit, as discussed in more detail below, with reference to <FIG>.

Focusing initially on the primary and standard function of the port, <NUM>, the port <NUM> (that of connecting a non-atmospheric pressure source to a wound dressing), the port <NUM> can be seen to include a generally tubular connector part <NUM> with a conduit <NUM> extending from a first aperture <NUM> configured to connect to a non-atmospheric pressure source, in the form of tubing. The connection being made by a simple push-fit of the tubing into the aperture, so that it is held in a resistance fit in the conduit <NUM>.

The conduit in this example opens into the side of a hemi-spherical chamber <NUM> provided in the underside of a dome <NUM>. Extending outwardly from the base of the dome <NUM> is an annular base plate <NUM>. The underside of the base plate <NUM> and the base of the dome provides a wound dressing contact surface at the base of the port <NUM>. The base plate <NUM> and dome <NUM> together form a housing. The base of the hemispherical chamber is open, and as such defines a second aperture <NUM>, which is provided in the wound dressing contact surface and is in fluid communication with the first aperture via the hemispherical chamber <NUM> and conduit <NUM>. As such the port is configured to allow fluid communication with the wound dressing via the first aperture <NUM> and second aperture <NUM>, which is orthogonal thereto. Of course, various alternative shapes and sizes of port may be determined by those skilled in the art. The port <NUM> of this embodiment (which is an embodiment useful for understanding the invention) also includes a piercing means configured to pierce the cover layer of a wound dressing as the wound dressing contact surface of the port <NUM> is applied to the wound dressing. In this embodiment, the piercing means is quite straightforward and takes the form of a cutting edge <NUM> formed integrally with the port, at the end of a downwardly depending annular projection <NUM> arranged around the aperture <NUM>. The piercing means of this embodiment (which is an embodiment useful for understanding the invention) is intended to cut a circular aperture, and therefore has a curved cutting edge <NUM>, which defines a circle (to allow a circular aperture to be cut into the wound dressing, to match the shape the aperture <NUM>). Alternatively, the cutting edge <NUM> could be provided on a blade (not shown) which could be attached to the base plate of the port in the same location as the cutting edge <NUM> on the annular projection <NUM>. This would allow for use of different materials, so that a material more suitable for the cutting edge, such as metal could be chosen, whilst a material more suitable for the port, e.g. plastics, in particular a relatively soft resilient plastic, could be chosen for the remainder of the port <NUM>. It is important that this predetermined extended distance by which the cutting edge <NUM> extends from the underside of the base plate <NUM> is carefully controlled, so as to control how far into the wound dressing the cutting edge <NUM> extends.

In particular, it can be provided that the cutting edge <NUM> cuts right through the covering layer <NUM> of a wound dressing, but not into any layer beneath. Alternatively, for example, where the port <NUM> is for use in a dressing with a pressure distribution layer sandwiched between a covering layer and an absorbent layer (as discussed below with reference to <FIG>), the cutting edge <NUM> can be arranged to extend through the covering layer <NUM>, to extend into the pressure distribution layer <NUM> and not to extend into the absorbent layer(s) <NUM> (or the wound contact layer <NUM>).

This means that fluid can pass through the aperture cut into the covering layer, whilst not cutting too deeply into the body of the dressing, so as to reduce damage to internal parts of the dressing, such as a pressure distribution layer, or an absorbent layer.

As an example, the predetermined extended distance may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, such as between <NUM> and <NUM>, for example about <NUM>.

If the cutting edge is sharp enough, it can be simply pushed onto the wound dressing to cut the aperture <NUM> as shown in <FIG>. The "chad" can then be removed, and the port <NUM> subsequently adhered around the aperture <NUM> in the wound dressing. Alternatively, to improve cutting, the port <NUM> could be twisted before adhering it to the wound dressing.

The possibility of twisting the port to cut the aperture means that a circular cutting edge is not necessary, a blade only defining part of a circle could be used to cut a circular aperture, or the cutting edge could even be replaced with a cutting point, on the end of a spike, to perforate the cover layer and thereby form one or more apertures, to be arranged in communication with the aperture <NUM> in the underside of the port.

It is considered that it may not always be necessary to remove the chad when cutting the aperture. As such, and as outlined above, apertures could be provided by piercing with a spike, similarly, a non-circular, or even non-curved blade could be provided on the port to cut an aperture in the form of a slit.

It will be understood from the above, that as the port <NUM> is applied to the dressing it cuts an aperture therein. The aperture may be cut at the same time as the port is attached, e.g. as it is adhered to the wound dressing. Obviously in that case, the step of removal of a chad by would be impossible, but it could simply be sucked out by a source of negative pressure.

With additional reference to <FIG>, illustrated therein is a schematic of another exemplary wound dressing <NUM> that can be selectively configured for use in a pressure gradient wound treatment system, using the port <NUM>.

The illustrated wound dressing <NUM> generally includes a covering layer <NUM> and an adhesive layer <NUM> for adhering the wound dressing <NUM> adjacent the wound. In certain embodiments, the wound dressing <NUM> further comprises a wound contact layer <NUM> for contacting the wound, a pressure dispersion layer <NUM>, a plurality of absorbent material layers <NUM> disposed between the wound contact layer <NUM> and the pressure dispersion layer <NUM>.

The covering layer <NUM> has a first surface <NUM> and a second surface <NUM>, and the first surface <NUM> is adjacent, and in contact with, the pressure dispersion layer <NUM> and the adhesive layer <NUM>. The covering layer <NUM> defines a cavity in which the pressure dispersion layer <NUM> is arranged. In certain embodiments, the covering layer <NUM> is formed of a polyurethane film. The covering layer <NUM> comprises optional indicia <NUM> in the form of a dashed circle, arranged in the optimal position for connection to a source of negative pressure.

The polyurethane film is transparent, so the indicia can be printed on the inside first surface <NUM> or the outside, second, surface <NUM> of the film layer <NUM>.

The adhesive layer <NUM> generally defines a border about an opening <NUM> for receiving the wound. In certain embodiments, the adhesive layer <NUM> comprises a silicone adhesive. In certain embodiments, the adhesive layer <NUM> may be perforated.

The wound contact layer <NUM> overlaps the border defined by the adhesive layer <NUM>, and is configured to contact the wound via the opening <NUM>. In certain embodiments, the wound contact layer <NUM> may comprise Medicel™. In certain embodiments, the wound contact layer <NUM> comprises carboxymethylated cellulose fibers. In certain embodiments, the wound contact layer <NUM> may comprise HYDROFIBER®. In certain embodiments, the wound contact layer <NUM> may be reinforced, for example via nylon stitching. Thus, the wound contact layer <NUM> may comprise reinforcing nylon stitching <NUM>.

The pressure dispersion layer <NUM> is adjacent and in contact with the first surface <NUM> of the cover layer <NUM>. In certain embodiments, the pressure dispersion layer <NUM> may be provided as a polyester foam layer. In certain embodiments, the pressure dispersion layer <NUM> comprises reticulated foam.

The absorbent material layers <NUM> are positioned between the wound contact layer <NUM> and the pressure dispersion layer <NUM>. The wound dressing <NUM> may, for example, comprise eight absorbent material layers <NUM>. In certain embodiments, one or more of the absorbent material layers <NUM> may comprise carboxymethylated cellulose fibers. In certain embodiments, one or more of the absorbent material layers <NUM> may comprise Medicel™. In certain embodiments, one or more of the absorbent material layers <NUM> may comprise HYDROFIBER®. In certain embodiments, one or more of the absorbent material layers <NUM> further comprises fenestrations <NUM>.

In certain embodiments, as shown in <FIG>, the wound dressing <NUM> may include an additional layer <NUM> between the pressure dispersion layer <NUM> and the uppermost absorbent layer <NUM>. The additional layer <NUM> may, for example, be formed of thermoplastic. In certain embodiments, the additional layer <NUM> may be provided as a thermoplastic spun lace layer. In certain embodiments, the wound dressing <NUM> may further comprise a nonwoven spun lace layer <NUM> connected to the wound contact layer <NUM>. In certain embodiments, an envelope structure <NUM> is formed by joining peripheral portions <NUM> of the thermoplastic spun lace layer <NUM> and the nonwoven spun lace layer <NUM> such that the plurality of absorbent material layers <NUM> are disposed substantially within an interior cavity <NUM> of the envelope structure <NUM>, for example as illustrated in <FIG>. In certain embodiments, the absorbent material layers <NUM> are disposed within the interior cavity <NUM> of the envelope structure <NUM>.

In certain embodiments, the wound dressing <NUM> may include a further layer <NUM> positioned between the wound contact layer <NUM> and the lowermost absorbent layer <NUM>. The further layer <NUM> may, for example, be a polyester/viscose layer.

As is well known, and therefore not shown, the wound dressing <NUM> may be provided with a removable release layer on the underside, covering the adhesive layer <NUM> and the underside of the wound contact layer <NUM>; and it may be individually packaged within a sterile package.

As illustrated in <FIG>, the wound dressing is configured for use without a pressure gradient wound therapy system. To use the wound dressing <NUM> without a pressure gradient wound therapy system, it is simply removed from its sterile packaging, then the release layer is simply removed and the dressing applied in the same way as an ordinary wound dressing. Again, it will be noted that in this configuration the entire region of the covering layer <NUM> within the peripheral adhesive border defined by the layer <NUM> is uninterrupted and closed, sealing the wound against microbes/bacteria that could cause infection.

<FIG> shows the wound dressing <NUM> of <FIG> configured for use with a pressure gradient wound therapy system. Here, a user has applied a port <NUM> of a second embodiment according to <FIG> (which shows an embodiment useful for understanding the invention) to the cover layer <NUM>.

The port <NUM> of <FIG> (which shows an embodiment useful for understanding the invention) is identical to that of <FIG> (which shows an embodiment useful for understanding the invention) in most respects and like numerals are used to identify like parts. The difference lies in the provision of a layer of adhesive <NUM> on the underside of the base plate <NUM> and a removable release layer <NUM> on the adhesive <NUM> and the fact that (although it cannot be seen from the figures) the cutting edge <NUM> is not a complete circle, but only defines a portion of a circle, e.g. <NUM> degrees.

To apply the port and simultaneously cut the aperture whilst attaching the port to the cover layer of the wound dressing the user removes the release layer <NUM> exposing the adhesive <NUM>. Then the user arranges the base of the port <NUM> on the covering layer <NUM> of the dressing <NUM> in the region of the indicia <NUM>.

The user then presses down on the upper surface of the port <NUM>. This pushes the cutting edge <NUM> into and through the covering layer <NUM>. Continued pressing ensures that the cutting edge extends right through the covering layer <NUM> and slightly into the pressure distribution layer <NUM>, but not into the layers beneath, whilst simultaneously adhering the port <NUM> to the wound dressing <NUM>.

Since the port is attached to the wound dressing <NUM> at the same time as the aperture is cut, and since only <NUM> degrees of the circle is cut, the "chad" will remain "hanging", attached at the edge of the opening, forming a door, which will be opened by the application of negative pressure applied via the second aperture <NUM> in the port <NUM> through the conduit <NUM> and chamber <NUM>.

As such, whilst the region of the covering layer <NUM> within the peripheral adhesive border defined by the layer <NUM> is now interrupted by the aperture, which forms an opening, it is simultaneously covered, by the port <NUM>.

A third embodiment of a port <NUM> is shown in <FIG> (which shows an embodiment useful for understanding the invention). The port <NUM> of the third embodiment is also specially configured, not only to carry out its primary function associated with prior art ports (i.e. to connect the wound dressing to a source of negative pressure), but also to pierce the covering layer of a wound dressing, whilst not cutting too deeply into the dressing. Of course, the port <NUM> may be provided in a sterile package and as part of a kit, as discussed in more detail below, with reference to <FIG>.

Focusing initially on the primary and standard function of the port, <NUM>, the port <NUM> (that of connecting a non-atmospheric pressure source to a wound dressing), the port <NUM> can be seen to include a short, generally tubular, connector part <NUM> with a conduit <NUM> extending from a first aperture <NUM> configured to connect to a non-atmospheric pressure source, in the form of tubing. The connection being made by a simple push-fit of the tubing into the aperture, so that it is held in a resistance fit in the conduit <NUM>.

The conduit <NUM> in this third embodiment (which is an embodiment useful for understanding the invention) extends through the port, with the short generally tubular connector part <NUM>, merging into a curved, intermediate part <NUM>, which has an angle of approximately <NUM> degrees, such that one end of the intermediate part <NUM> is substantially perpendicular to the other.

Extending radially outwardly from the end of the curved intermediate part <NUM> distal from the tubular connector part <NUM> is a skirt <NUM>. The skirt <NUM> forms a housing; it is dome-shaped and terminates in a rim or lip <NUM> which serves as a base of the port <NUM> and constitutes one part of a wound dressing contact surface of the port <NUM>. The rim <NUM> is provided with an adhesive underside to adhere to a wound dressing <NUM>.

The adhesive underside of the wound dressing contact surface may of course be covered by a release liner (not shown). The rim <NUM> of the skirt <NUM> is orthogonal to the first aperture <NUM> of the connector part <NUM> which receives the tubing, so that in use, with the rim <NUM> of the skirt <NUM> adhered to the top of the wound dressing <NUM>, the tubing extends in a direction substantially parallel with the plane of the wound dressing.

Within the skirt <NUM>, the conduit <NUM> continues from the end of the intermediate part <NUM> (downwardly in use) and is defined by a tubular piercing part <NUM>, which is the piercing means of this second embodiment (which is an embodiment useful for understanding the invention). The tubular piercing part <NUM> includes a second aperture <NUM> which also contacts (and is in fluid communication with) the wound dressing in use, and as such constitutes another part of a wound dressing contact surface of the port <NUM>. The conduit <NUM> extends between the first aperture <NUM> and the second aperture <NUM>, providing fluid communication between the two apertures <NUM>, <NUM>. As such the port is configured to allow fluid communication with the wound dressing via the first aperture <NUM> and second aperture <NUM>, which is orthogonal thereto. Of course, various alternative shapes and sizes of port may be determined by those skilled in the art. The end of the tubular piercing part <NUM> constitutes a cutting edge. The end is formed at an oblique angle, so as to create a piercing tip <NUM> (in as similar fashion to the well-known piercing drinking straws provided with children's drinks cartons, as described in the prior art section of <CIT> and the tips of needles). Moreover, the end of the tubular piercing part <NUM> is provided with an optional internal bevel <NUM> to further sharpen the cutting edge. As with the other embodiments, the piercing means is configured to pierce the cover layer of a wound dressing as the wound dressing contact surface of the port <NUM> is applied to the wound dressing. In this embodiment (which is an embodiment useful for understanding the invention) too, the cutting edge of the piercing part <NUM> is formed integrally with the port, but naturally, again, a separate blade could be attached at the end of, or could even form, the tubular piercing part <NUM>.

Again, the piercing means of this embodiment (which is an embodiment useful for understanding the invention) is intended to cut a circular aperture, and therefore has a curved cutting edge. As noted above, it is important that this predetermined extended distance by which the cutting edge extends from the underside of the base of the port is carefully controlled, so as to control how far into the wound dressing the cutting edge extends. As such, in this an example, the predetermined extended distance by which the piercing tip <NUM> extends beyond the plane of the underside of the skirt <NUM>, which defines the wound dressing contact surface, may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, such as between <NUM> and <NUM>, for example about <NUM>. To cut a circular aperture in the wound dressing, as shown in <FIG> (which shows an embodiment useful for understanding the invention), the port is pushed onto the wound dressing <NUM>, such that the piercing tip cuts though the covering layer3; the skirt <NUM> acts as a stop preventing over-insertion. The port <NUM> is then twisted so as to cut a circular aperture in the cover layer <NUM>, and the release liner (not shown) removed from the underside of the skirt and the port <NUM> adhered in place, with the aperture <NUM> at the bottom of the conduit, coaxial with the aperture cut in the covering layer <NUM> to draw fluid through it. The "chad" can either be removed by hand, or sucked out through the conduit in use. As an alternative to twisting, the port <NUM> can simply be pressed onto the wound dressing <NUM>, cutting an aperture in the cover layer, but potentially not cutting a "chad" out, rather leaving it "hanging". This need not cause a problem as fluid can flow past the hanging chad. Once again it will be understood that as the port <NUM> is applied to the dressing it cuts an aperture therein. The aperture may be cut at the same time as the port is attached, e.g. as it is adhered to the wound dressing. Obviously in that case, the step of removal of a chad by would be impossible, but it could simply be sucked out by a source of negative pressure.

A fourth embodiment of a port <NUM> is shown in <FIG>. The port <NUM> of the third embodiment is also specially configured, not only to carry out its primary function associated with prior art ports (i.e. to connect the wound dressing to a source of negative pressure), but also to pierce the covering layer of a wound dressing, whilst not cutting too deeply into the dressing. Of course, the port <NUM> may be provided in a sterile package and as part of a kit, as discussed in more detail below, with reference to <FIG>.

Focusing initially on the primary and standard function of the port <NUM>, (that of connecting a non-atmospheric pressure source to a wound dressing), the port <NUM> can be seen to include a short, generally tubular, connector part <NUM> with a conduit <NUM> extending from a first aperture <NUM> configured to connect to a non-atmospheric pressure source, in the form of tubing. The connection is made by a simple push-fit of the tubing into the aperture <NUM>, so that it is held in a resistance fit in the conduit <NUM>.

The conduit <NUM> in this fourth opens into the side of a large generally shallow cylindrical chamber <NUM>, defined primarily by a shell <NUM> having the shape of a shallow, brimmed hat. The brimmed-hat shaped shell is formed of a resiliently flexible material, such as sort plastic, so that the top forms an actuator, which can be pushed downwards and will resile upwards.

The brimmed hat shaped shell <NUM> sits on an annular base plate <NUM>. The annular base plate <NUM> has the same outer outline as the brim of the shell <NUM>, but a smaller opening than that at the base of the shallow cylindrical chamber <NUM>. The annular base pate <NUM> is formed of a hard plastic material and thus provides rigidity. The underside of the base plate <NUM> and the base of the dome provides a wound dressing contact surface at the base of the port <NUM>. The base plate <NUM> and shell <NUM> together form a housing. The base of the hemispherical chamber is open, but on account of its smaller inner diameter, the opening in the base plate <NUM> defines a second aperture <NUM>, which is provided in the wound dressing contact surface and is in fluid communication with the first aperture via the shallow cylindrical chamber <NUM> and conduit <NUM>. As such the port is configured to allow fluid communication with the wound dressing via the first aperture <NUM> and second aperture <NUM>, which is orthogonal thereto. Of course, various alternative shapes and sizes of port may be determined by those skilled in the art.

The port <NUM> of this embodiment also includes a piercing means configured to pierce the cover layer of a wound dressing as the wound dressing contact surface of the port <NUM> is applied to the wound dressing. In this embodiment, the piercing means is more sophisticated and the form of a cutting edge <NUM> formed integrally with a flexure disc spring <NUM> shown separately in <FIG>. The cutting edge <NUM> is provided at the end of a downwardly depending annular projection <NUM> extending from the disc spring <NUM> and configured to extend through the aperture <NUM>. The annular projection <NUM> is stepped, such that it is provided with a shoulder <NUM>, the shoulder having a larger diameter than the aperture <NUM> in the base plate <NUM> and therefore defining the extent to which the blade <NUM> can extend into the wound dressing.

The piercing means of this embodiment is once again intended to cut a circular aperture, and therefore has a curved cutting edge <NUM>, which defines a circle (to allow a circular aperture to be cut into the wound dressing, to match the shape the aperture <NUM>). In this embodiment the cutting edge <NUM> is serrated. Obviously the blade need not be serrated (as in the other embodiments).

The cutting edge <NUM> and the disc spring <NUM> from which it depends are, advantageously, made of metal. The outer peripheral edge <NUM> of the disc spring is fitted into a corresponding circular groove in the shell <NUM>. The groove extends radially outwardly into the sidewall of the shell, near its top. As such, the top of the shell is an actuator, acting as a button, and pressing downwardly on the top of the resilient shell pushes the centre of the spring downwards. The cutting edge <NUM> extends downwardly near the centre of the disc spring <NUM>, and as such it moves downward when the button is pressed.

It is important that this predetermined extended distance by which the cutting edge <NUM> extends from the underside of the base plate <NUM> is carefully controlled, so as to control how far into the wound dressing the cutting edge <NUM> extends.

The extent to which the cutting edge extends is defined by the shoulder <NUM> and as an example, the predetermined extended distance may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, such as between <NUM> and <NUM>, for example about <NUM>.

The extent to which the cutting edge retracts is similarly carefully controlled and as an example, the predetermined retracted distance may be greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM>; greater than <NUM> or greater than <NUM>. The predetermined distance may be less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; less than <NUM>; or less than <NUM>. For example, the predetermined distance may be between <NUM> and <NUM>, such as between <NUM> and <NUM>, for example about <NUM>.

If the cutting edge is sharp enough, it can be simply pushed onto the wound dressing to cut the aperture <NUM> as shown in <FIG>. The retraction of the blade allows plenty of space beneath it for fluid to be sucked into the chamber <NUM> and out through the conduit <NUM>. As such, the "chad" need not necessarily be removed, and the port <NUM> can be adhered around the aperture <NUM> in the wound dressing at the same time that it cuts the hole. Alternatively, to improve cutting, the port <NUM> could be twisted before adhering it to the wound dressing. Preferably the underside of the base plate <NUM> is provided with an adhesive (not shown) and a release liner (not shown), for example a double-sided adhesive tape.

With additional reference to <FIG>, illustrated therein is a pressure gradient wound therapy system <NUM> according to certain embodiments. The pressure gradient wound therapy system <NUM> comprises a pump <NUM> for generating negative pressure, a wound dressing <NUM> (which may be the wound dressing <NUM> or <NUM> described above) for covering and protecting a wound, an inline filter <NUM>, a first pressure tube <NUM> having a first interior lumen <NUM>, a second pressure tube <NUM> having a second interior lumen <NUM>, and connected to a port <NUM>/<NUM>/<NUM>. The first pressure tube <NUM> is disposed between the pump <NUM> and the inline filter <NUM>. The second pressure tube <NUM> is disposed between the inline filter <NUM> and the port <NUM>/<NUM>/<NUM>. The port <NUM>/<NUM>/<NUM> is disposed between the second pressure tube <NUM> and the wound dressing <NUM> such that the pump <NUM> and the wound dressing <NUM> are in fluid communication via the interior lumens <NUM>, <NUM>.

The port <NUM>/<NUM>/<NUM> is preferably provided in a kit and most preferably arranged in the kit within a sterile package. As illustrated schematically in <FIG>, the kits can comprise a port <NUM>/<NUM>/<NUM> within a sterile package <NUM> and at least one of the following items, all of which are included in this exemplary kit:.

For use where it is envisioned that a wound will initially require treatment with a pressure gradient wound therapy system, the kit may comprise a port <NUM>/<NUM>/<NUM> and one or more of items d and e, for example both of items, d, and e, and optionally items a and/or b and/or c as well. As such, the user can be provided with all the equipment required to use the wound dressings <NUM>/<NUM>/<NUM> with a pressure gradient wound therapy system.

In order to use such a kit, the user (e.g. a patient or HCP) can cut an aperture in a dressing <NUM>/<NUM>/<NUM>, optionally in the region of indica, using the piercing means of the port <NUM>/<NUM>/<NUM>; attach the port <NUM>/<NUM>/<NUM> thereto, around the aperture, and in fluid communication therewith; attach one end of the tubing <NUM> to the port <NUM>/<NUM>/<NUM> and the other to the pump <NUM> and run the pump <NUM> to provide non-atmospheric (e.g. negative) pressure to the wound.

Then, if/when the pressure gradient therapy is no longer necessary, the user can use up any remaining wound dressings <NUM>/<NUM>/<NUM> without the pressure gradient wound therapy system, by applying them to the wound without cutting an aperture in the dressings <NUM>/<NUM>/<NUM>, so as to maintain a sealed environment around the wound.

On the other hand, for use where it is envisioned that a wound does not initially require treatment with a pressure gradient wound therapy system (and most preferably where it is envisioned that a wound does not require treatment with a pressure gradient wound therapy system, but it is considered that there is a risk that the wound will not heal well without a pressure gradient so in future, pressure gradient wound therapy might be useful), the kit may comprise the port <NUM>/<NUM>/<NUM>, one or preferably a plurality of the dressings of item c, and preferably one or both of items a and b. As such, the user has the dressings which can be used without a pressure gradient wound therapy system and can simply apply a dressing <NUM>/<NUM>/<NUM> to the wound in the configuration for use without a pressure gradient wound therapy system. Thus the user simply remove the release layer and apply the dressing to the wound without cutting an aperture in the region of the indicia <NUM>, <NUM>, so that the cover layer is uninterrupted and closed within the adhesive border, and the is wound sealed against bacteria/microbes.

Then, should it be determined that the wound would benefit from pressure gradient therapy (e.g. negative pressure), the user can follow the instructions from the packaging/instructions (where included), and cut a hole in the covering layer <NUM>/<NUM> in the region of the indicia <NUM>/<NUM> using the piercing means of the port <NUM>/<NUM>/<NUM> and apply a pressure gradient wound therapy system as outlined above (sourced for example from another kit), without having to first remove the dressing <NUM>/<NUM>/<NUM> (which can present an opportunity for infection).

For use where it is determined after the event that NPWT would be useful the kit could include a port and one or more of items d, and e, for example both of items, d, and e, and optionally items a and/or b and/or c as well would be useful. As such, the user can be provided with all the equipment required to convert a wound dressing <NUM>/<NUM>/<NUM> in-situ for use with a pressure gradient wound therapy system.

Each of the documents referred to above is incorporated herein by reference. Except in Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, device dimension, and the like, are to be understood as modified by the word "about.

Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

Claim 1:
A port (<NUM>) for connecting a non-atmospheric pressure source to a wound dressing (<NUM>), the port comprising: a first aperture (<NUM>) configured to connect to the non-atmospheric pressure source; a wound dressing contact surface; the wound dressing contact surface comprising a second aperture (<NUM>) in fluid communication with the first aperture (<NUM>) and configured to allow fluid communication with the wound dressing (<NUM>); and a piercing means configured to pierce the wound dressing (<NUM>) as the wound dressing contact surface of the port (<NUM>) is applied to the wound dressing (<NUM>), wherein the port (<NUM>) further comprises a housing, wherein the piercing means is configured to extend from the housing, wherein the port is characterised in that the piercing means is configured to be retractable into the housing.