Patent Description:
Transparent film dressings are widely used as protective layers over wounds because they facilitate healing in a moist environment while acting as a barrier to contaminating liquids and bacteria. The films are also used as surgical drapes because of their barrier properties. Dressings and drapes fitting the above description are available under a number of trade names such as TEGADERM™ (<NUM> Company, St. Paul, MN) and OP-SITE™ (Smith & Nephew, Hull, England).

The polymeric films used in those dressings and drapes are conformable, i.e., the films are extremely thin, flexible and supple. They are typically supplied with a releasable protective liner covering the adhesive coated surface of the film. When the liner is removed, the adhesive coated film tends to wrinkle and adhere to itself, interfering with the smooth, aseptic application of the dressing to a patient's skin. Various delivery systems have been proposed to address this problem such as those disclosed in <CIT>. The use of a removable carrier, which does not require tearing of the film after it has been placed on the patient, avoids the problems described above. The carrier also aids in accurate placement of the dressing on a patient.

Thin polymeric films that are flexible and resilient are beneficial when used on skin that flexes, stretches, and retracts. However, for some application, like when securing devices such as tubing, ports, and catheters, the high flexibility and resiliency of the thin polymeric film can cause too much movement of the secured medical device. Therefore, medical dressings have been developed that further incorporate areas having secured to the thin polymeric film, stiffer, less conformable materials such as adhesives, films, or fabrics. For example, <CIT> discloses an adhesive composite that includes a conformable backing and a permanent adhesive reinforcement around the periphery of the adhesive composite. One example of a commercially available medical dressing with a reinforcement layers is TEGADERM™ IV Advanced Dressing (<NUM> Company, St.

In some instances medical dressings are applied to a patient and remain in place for several days. When dressings are worn over time, the edge of the dressing can begin to peel away from the patient possibly resulting in contamination at the site or adhesive failure entirely. The use of less resilient materials to add stiffness and less flexibility to areas of the dressing can contribute to adhesive failure of the dressing on skin. When the skin flexes and stretches, but the less resilient material cannot, then the adhesive will pull away from the skin. A need remains for a medical dressing that can strongly secure to skin, while also being highly flexible and conformable over skin.

<CIT> relates to a wound care article, comprising at least one sheet-like layer. The sheet-like layer has at least two wings and a central region, the wings being arranged around the central region and the wings being joined to each other via the central region.

<CIT> relates to a self-adherent window dressing including a fabric layer bounded by an edge. The fabric layer has an adhesive side, an opposite non-adhesive side, and an opening therein to allow for viewing therethrough. A reinforcement member is adhered to at least a portion of the fabric layer. A transparent film layer closes the opening and has first and second opposing sides. The film layer first side is non-adhesive and is mounted on the fabric layer adhesive side to close the opening in the fabric layer. The film layer second side has a skin adhering adhesive portion and an adhesive-free portion. The adhesive-free portion is disposed inwardly of the opening. The film layer adhesive-free portion is adapted not to stick to a wound, connector, or catheter disposed between the film layer adhesive-free portion and skin.

<CIT> relates to a wound dressing comprising an absorbent pad, an adhesive layer, and a backing layer, along with a dressing support layer configured to retain and deliver the wound dressing to a wound, the dressing support layer having a radial configuration that forms a plurality of alternating covered and uncovered portions of the backing layer along the perimeter of the wound dressing.

<CIT> relates to a window dressing with an integral anchor including a fabric layer having juxtaposed insertion site viewing and anchor member portions. The fabric layer has an adhesive side and an opposite non-adhesive side. The insertion site viewing portion is defined by an opening in the fabric layer. A transparent film layer having an adhesive skin-adhering side and an opposite non-adhesive side is adhered to the fabric layer adhesive side and closes the opening in the fabric layer. The anchor member portion includes a reinforcing structure disposed on the fabric layer. The reinforcing structure has an adhesive side and an opposite non-adhesive side. The non-adhesive side is adhered to the fabric layer adhesive side. A first removable securement device may be removably connected to the anchor member portion opposite the insertion site viewing portion, and a second removable securement device may be removably connected to the first removable securement device.

The disclosed medical dressing is highly flexible and conformable over skin, while maintain strong adhesive securement to skin over extended periods of time. The dressing comprises a backing layer, support material, and a plurality of specifically placed slits in the support material, which allow for stretching and recovery of the backing layer.

In one embodiment, the medical dressing comprises a first major surface, second major surface, opposite the first major surface, and a perimeter, wherein the second major surface comprises an adhesive. The dressing comprises a backing layer that is elastic, a support material secured to the backing layer that is less elastic than the backing layer, a plurality of slits through the support material, wherein each slit is a long narrow through cut in the support material, and wherein each slit is spaced from an adjacent slit.

"Elastic" means a material able to elongate and regain some or all of its original shape.

"Slit" means a long, narrow through cut. In one embodiment, the slit has a length that is significantly longer that a width. In one embodiment, the slit has a length at least <NUM> times greater than a width. In one embodiment, the slit has a length at least <NUM> times greater than a width. In one embodiment, the slit has essentially no width.

The words "preferred" and "preferably" refer to embodiments that may afford certain benefits, under certain circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments.

As used herein, "a," "an," "the," "at least one," and "one or more" are used interchangeably. The term "and/or" (if used) means one or all of the identified elements or a combination of any two or more of the identified elements.

While the above-identified drawings and figures set forth embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope of this invention.

<FIG> is a first embodiment of a medical dressing <NUM> comprising a plurality of slits <NUM>. The medical dressing shown in <FIG> is a dressing used to cover the site of an inserted intravenous catheter. Overall, the medical dressing <NUM> has a first major surface <NUM> and second major surface <NUM>, which is opposite the first major surface <NUM>. At least a portion of the second major surface <NUM> comprises an adhesive <NUM>. A perimeter <NUM> surrounds the medical dressing <NUM> and defines a dressing area <NUM>.

The medical dressing <NUM> has a backing layer <NUM> and a support material <NUM> that is secured to the backing layer <NUM>. Through at least the support material <NUM> are a plurality of slits <NUM>. In <FIG> and in the other images, the slits <NUM> are depicted as a relatively thick black line so as to clearly communicate the location of the slit <NUM> on the dressing <NUM>. It is understood that the slit <NUM> can be simply a through cut and therefore not having the thickness as depicted in these images.

<FIG> is a side sectional view of <FIG> through line <NUM>-<NUM>. In this embodiment, the backing layer <NUM> forms the first major surface <NUM>. In this embodiment, the support material <NUM> extends adjacent the entire perimeter <NUM>, but is not continuous across the entire dressing area <NUM>. As best seen in <FIG>, the support material <NUM> is not located in a central window <NUM> of the medical dressing <NUM>, while allows for a transparent window to view the inserted catheter. It is both the backing layer <NUM> and the support material <NUM> making up the second major surface <NUM>. In this embodiment, the adhesive <NUM> covers the entire second major surface <NUM>.

It is understood that the adhesive <NUM> may cover only a portion of the second major surface <NUM>. For example, in the embodiment shown in <FIG>, the adhesive <NUM> may cover only the portion of the second major surface <NUM> having the support material <NUM>, which would be the portion adjacent the perimeter.

<FIG> shows the backing layer <NUM> at the first major surface <NUM>, while the support material <NUM> is at the second major surface <NUM>. In one embodiment, the support material <NUM> may be at the first major surface <NUM> and the backing layer <NUM> at the second major surface <NUM>. It is understood that one or more additional layers may be included adjacent the backing layer <NUM>, support material <NUM>, between the backing layer <NUM> and support material <NUM>.

Generally, the backing layer <NUM> will extend over the entire dressing area <NUM> as it is the portion of the dressing <NUM> that provides a barrier against external contamination to the underlying substrate. The support material <NUM> is shown in the embodiment of <FIG> covering only a portion of the dressing area <NUM>; however, in other embodiments the support material <NUM> may cover nearly the entire dressing area <NUM>.

The sectional view of <FIG> passes directly through slits <NUM>. As can be seen in <FIG>, the slits <NUM> are only in the support material and extend from the perimeter <NUM> into a portion of the dressing area <NUM>. The slit <NUM> does not entirely transverse the support material. Each slit <NUM> is separate from, and disconnected from another adjacent slit <NUM>.

The backing layer <NUM> is elastic and a sufficiently impermeable barrier to the passage of liquids and at least some gases, which protects the covered site from external contaminants. Being elastic allows for the backing layer <NUM> to expand, contract, stretch and recover as the underlying substrate, such as skin, moves.

Elasticity can be measured in any number of commonly used means for evaluating stretch and recovery of a material. In one embodiment, the backing layer <NUM> (independent of the support material) has an elongation to break of at least <NUM>%. In one embodiment, the backing layer <NUM> (independent of the support material) has an elongation to break of less than <NUM>%. In one embodiment, the support material <NUM> (independent of the backing layer) has an elongation to break of at least <NUM>%. In one embodiment, the support material <NUM> (independent of the backing layer) has an elongation to break of at least <NUM>%. In one embodiment, the support material <NUM> has an elongation to break less than <NUM>%.

Elasticity can be measured by an initial modulus of elasticity, which is the force require to apply a specified amount of stretch. In one embodiment, the backing layer <NUM> has a modulus, at <NUM>% elongation, of less than <NUM> Newtons. In one embodiment, the backing layer <NUM> has a modulus, at <NUM>% elongation, of less than <NUM> Newtons. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM> in the first portion with slits <NUM>, the modulus at <NUM>% elongation is less than <NUM> Newtons. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM> in the first portion with slits <NUM>, the modulus at <NUM>% elongation is less than <NUM> Newton. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM> in the second portion without slits, the modulus at <NUM>% elongation is greater than <NUM> Newton and less than <NUM> Newtons. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM> in the second portion without slits, the modulus at <NUM>% elongation is greater than <NUM> Newton and less than <NUM> Newtons. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM>, the ratio of the modulus at <NUM>% elongation of the second portion without slits to the modulus at <NUM>% of the first portion with slits is at least <NUM>:<NUM>. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM>, the ratio of the modulus at <NUM>% elongation of the second portion without slits to the modulus at <NUM>% of the first portion with slits is at least <NUM>:<NUM>. In one embodiment, when the support material <NUM> is secured with the backing layer <NUM>, the ratio of the modulus at <NUM>% elongation of the second portion without slits to the modulus at <NUM>% of the first portion with slits is at least <NUM>:<NUM>.

The support material <NUM> is secured to the backing layer <NUM>, through adhesive, thermal bonding, lamination, or other commonly used securement techniques. The support material <NUM> provides structural strength to the medical dressing <NUM>, and therefore, independently, is less elastic that the backing layer <NUM>. In one embodiment, the support material, independently, has essentially no elasticity, such that is may be unable to stretch and/or it may be unable to recover from a stretch. In one embodiment, the support material, may be more elastic in one direction (machine direction) than in the cross direction (transverse direction), but overall is has less elasticity than the backing layer <NUM>.

<FIG> is an enlarged top view of the medical dressing <NUM> of <FIG>, showing the stretching of the dressing <NUM> at several slits <NUM>. When the dressing <NUM> is subject to elongation, the elastic backing layer <NUM> will stretch, but the less elastic support material <NUM> is less able to stretch or recover. However, the slits <NUM> allow the support material <NUM> to extend and therefore allow for elongation of the backing layer <NUM> at the slit, which can be seen in <FIG>. The elasticity of the backing layer <NUM>, when recovering from the stretch, will also recover the attached support material <NUM>, returning the dressing <NUM> much to the configuration as shown in <FIG>. Therefore, the slits allow for control of the stretch and recovery of discrete areas of the support material.

In some circumstances, more stretching occurs at the perimeter <NUM> of the dressing. Therefore, in the embodiment shown in <FIG>, the plurality of slits <NUM> are located along at least a portion of the perimeter <NUM> of the dressing <NUM>. The slits <NUM> at the perimeter <NUM> begin directly at the perimeter <NUM> and extend partially in to the support material <NUM>. In this embodiment, the slits <NUM> are located along the entire perimeter <NUM>. The slits <NUM> may have a variety of sizes or shapes, and it is understood that each slit can have a size and shape the same as or different from the other slits <NUM> on the dressing <NUM>.

In one embodiment, the slits <NUM> are at least <NUM> in length. In one embodiment, the slits <NUM> are at least <NUM> in length. In one embodiment, the slits are less than <NUM> in length. In one embodiment, the slits are less than <NUM> in length.

In one embodiment, such as shown in <FIG>, the slits <NUM> are a through cut in the support material and have essentially no width, meaning that no material was removed from the support material during cutting. In one embodiment, the slits have a width less than <NUM>. In one embodiment the slits have a width less than <NUM>.

In one embodiment, the slits <NUM> at the perimeter <NUM> are shown extending in a straight line inward, generally perpendicular to the part of the perimeter <NUM> it is understood that any shape or placement of the slits <NUM> at the perimeter could achieve the same purpose of allowing expansion and contraction of the backing layer <NUM> at the perimeter <NUM>.

In the embodiment shown in <FIG> the slits <NUM> are only through the support material <NUM>. It is understood that depending on the particular arrangement of layers or the particular application of the dressing the slit <NUM> may extend to both the backing layer and support material <NUM>.

Selectively placed slits <NUM> allow for some portions of the medical dressing <NUM> to have more elasticity than portions of the dressing <NUM> with the support material <NUM> that do not have the slits <NUM>. For example, in the embodiment shown in <FIG>, the dressing area <NUM> has a first portion <NUM> adjacent the perimeter <NUM> with slits that have more elasticity that a second portion <NUM> of the dressing area <NUM> having support material <NUM> but without slits <NUM>. This is desirable as underlying medical devices or tubing at the second portion <NUM> should not be allowed to stretch as much as portions of the dressing <NUM> at the perimeter <NUM>.

If the support material <NUM> did not have slits, when the dressing <NUM> is subject to elongation, the elastic backing layer <NUM> will stretch, but the less elastic support material <NUM> is less able to stretch or recover. Therefore, if the underlying substrate, for example skin, continues to stretch beyond the ability of the support material <NUM> to stretch, then the adhesion between the adhesive <NUM> and the underlying substrate will begin to break. In some circumstances, more stretching occurs at the perimeter <NUM> of the dressing. When the adhesion breaks at the perimeter, then the edges of the dressing begin to lift away from the skin.

Reference to similar structural components from one embodiment to another will use the same reference numbers. Unless noted otherwise, description applicable from one embodiment has applicability to other similar embodiments.

<FIG> is a second embodiment of a medical dressing <NUM> comprising a plurality of slits <NUM> within in dressing area <NUM>. In this embodiment, the dressing area <NUM> includes a first portion <NUM> having the plurality of slits <NUM>, and a second portion <NUM> with support material <NUM> without slits. The arrangement of slits <NUM> is generally radially outward from the first portion <NUM> so that there is a pocket that can form when the support material <NUM> and attached backing layer <NUM> are allowed to stretch. The location of the first portion <NUM> of the dressing area, containing the slits <NUM> coincides with the location of an underlying medical devices or tubing. As described with respect to <FIG>, the slits <NUM> allow for expansion of the support material, while the barrier layer stretches to better conform with the underlying medical device or tubing, while the strength of the support material still prevents excessive stretching and movement of the medical device or tubing.

It is understood that a single dressing may include one or more select areas may each have a plurality of slits <NUM>. For example, a single dressing may have an arrangement of slits <NUM> within the dressing area <NUM> such as shown in <FIG> and an arrangement of slits <NUM> at the perimeter <NUM> such as shown in <FIG>.

<FIG> is a third embodiment of a medical dressing <NUM>, specifically a tape, comprising a plurality of slits <NUM>. In this embodiment, the plurality of slits <NUM> extend along opposing portions of the longitudinally extending sides of the perimeter <NUM>. In this embodiment, the support material <NUM> covers the entire dressing area <NUM>. As with other embodiments, each slit <NUM> is separate from an adjacent slit <NUM>. The slits <NUM> at opposing portions of the longitudinally extending sides of the perimeter <NUM> may or may not align with one another. This arrangement of slits <NUM> allows for improved stretching and recovery in a direction along the longitudinally extending medical dressing <NUM>.

<FIG> is a fourth embodiment of a medical dressing <NUM>, specifically a tape, comprising a plurality of slits <NUM>. In this embodiment, the plurality of slits <NUM> extend throughout the entire dressing area <NUM>. The some slits <NUM> are arranged perpendicular to other slits. Therefore, this dressing will allow for improved stretching and recover in a direction along the longitudinally extending medical dressing <NUM>, as well as perpendicular to the longitudinally extending medical dressing <NUM>. For either embodiment shown in <FIG>, it is understood that the tape could be provided in a variety of shapes and sizes of precut tape sections or the tape may be an elongated, longitudinally extending tape that could be provided in roll form.

The medical dressing disclosed may be made by conventional techniques (e.g., extrusion, solvent casting, calendaring, laminating, adhesive coating, and the like) which are familiar to those skilled in the art. <CIT> discloses constructions and methods for making medical dressings with backing layers and support material. It will be understood that the slits can be applied during the rotary converting process.

The medical dressings are useful to provide an impermeable barrier to the passage of liquids and at least some gases. Representative barriers may include non-woven and woven fibrous webs, knits, films, foams polymeric films and other familiar backing materials. In some embodiments, a transparent substrate is desirable to allow for viewing of the underlying skin or medical device.

In one embodiment, the substrate has high moisture vapor permeability, but generally impermeable to liquid water so that microbes and other contaminants are sealed out from the area under the substrate. One example of a suitable material is a high moisture vapor permeable film such as described in <CIT> and <CIT>. In high moisture vapor permeable film/adhesive composites, the composite should transmit moisture vapor at a rate equal to or greater than human skin such as, for example, at a rate of at least <NUM>/m<NUM> /<NUM> hrs at <NUM>/<NUM>-<NUM>% RH, or at least <NUM>/m<NUM> /<NUM> hrs at <NUM>/<NUM>-<NUM>% RH, or at least <NUM>/m<NUM> /<NUM> hrs at <NUM>/<NUM>-<NUM>% RH using the inverted cup method as described in <CIT>. Perforated substrates or films or pattern coated adhesives may be used to increase the moisture vapor transmission. In one embodiment, the substrate is an elastomeric polyurethane, polyester, or polyether block amide films. These films combine the desirable properties of resiliency, elasticity, high moisture vapor permeability, and transparency. A description of this characteristic of backing layers can be found in issued <CIT> and <CIT>.

Commercially available examples of potentially suitable backing materials may include the thin polymeric film backings sold under the trade names TEGADERM (<NUM> Company), OPSITE (Smith & Nephew), etc. Many other backings may also be used, including those commonly used in the manufacture of surgical incise drapes (e.g., incise drapes manufactured by <NUM> Company under the trade names STERIDRAPE and IOBAN), etc..

Because fluids may be actively removed from the sealed environments defined by the medical dressings, a relatively high moisture vapor permeable backing may not be required. As a result, some other potentially useful backing materials may include, e.g., metallocene polyolefins and SBS and SIS block copolymer materials could be used.

Regardless, however, it may be desirable that the backing be kept relatively thin to, e.g., improve conformability. For example, the backing layer may be formed of polymeric films with a thickness of <NUM> micrometers or less, or <NUM> micrometers or less, potentially <NUM> micrometers or less, or even <NUM> micrometers or less.

The support material provides strength to the thin, flexible backing layer. The support material therefore has more stiffness and less elasticity than the backing layer. The support material may be a coating, such as an adhesive, or may be a self-supporting substrate such as another film, woven, knitted, or nonwoven fabric. For example, <CIT> discloses a permanent adhesive as a reinforcement that could be used as the support material.

One example of nonwoven for the support material is a high strength nonwoven fabric available from E. Dupont de Nemours & Company of Wilmington, Delaware under the trademark Sontara, including Sontara <NUM>, a hydroengangled polyester fabric. Other suitable nonwoven webs include a hydroentangled polyester fabric available from Veratec, a division of International Paper of Walpole, Mass. Another suitable nonwoven web is the nonwoven elastomeric web described in <CIT>.

Suitable adhesive for use in wound dressing articles include any adhesive that provides acceptable adhesion to skin and is acceptable for use on skin (e.g., the adhesive should preferably be nonirritating and non-sensitizing). Suitable adhesives are pressure sensitive and in certain embodiments have a relatively high moisture vapor transmission rate to allow for moisture evaporation. Suitable pressure sensitive adhesives include those based on acrylates, urethane, hyrdogels, hydrocolloids, block copolymers, silicones, rubber based adhesives (including natural rubber, polyisoprene, polyisobutylene, butyl rubber etc.) as well as combinations of these adhesives. The adhesive component may contain tackifiers, plasticizers, rheology modifiers as well as active components including for example an antimicrobial agent.

The pressure sensitive adhesives that may be used in the wound dressings may include adhesives that are typically applied to the skin such as the acrylate copolymers described in <CIT>, particularly a <NUM>:<NUM> isooctyl acrylate:acrylamide copolymer. Another example may include a <NUM>:<NUM>:<NUM> isooctyl acrylate: ethyleneoxide acrylate:acrylic acid terpolymer, as described in <CIT> (Example <NUM>). Other potentially useful adhesives are described in <CIT>; <CIT>; <CIT>; and <CIT>. Inclusion of medicaments or antimicrobial agents in the adhesive is also contemplated, as described in <CIT> and <CIT>.

Silicone adhesive can also be used. Generally, silicone adhesives can provide suitable adhesion to skin while gently removing from skin. Suitable silicone adhesives are disclosed in <CIT> and <CIT>.

The pressure sensitive adhesives may, in some embodiments, transmit moisture vapor at a rate greater to or equal to that of human skin. While such a characteristic can be achieved through the selection of an appropriate adhesive, it is also contemplated that other methods of achieving a high relative rate of moisture vapor transmission may be used, such as pattern coating the adhesive on the backing, as described in <CIT>. Other potentially suitable pressure sensitive adhesives may include blown-micro-fiber (BMF) adhesives such as, for example, those described in <CIT>. The pressure sensitive adhesive used in the wound dressing may also include one or more areas in which the adhesive itself includes structures such as, e.g., the microreplicated structures described in <CIT>.

Issued <CIT> and <CIT> describe methods of making such films and methods for testing their permeability. Preferably, the film/adhesive composite should transmit moisture vapor at a rate equal to or greater than human skin. Preferably, the adhesive coated film transmits moisture vapor at a rate of at least <NUM>/m<NUM>/<NUM> hrs/<NUM>□C/<NUM>-<NUM>% RH, more preferably at least <NUM>/m<NUM>/<NUM> hrs/<NUM>□C/<NUM>-<NUM>% RH, and most preferably at least <NUM>/m<NUM>/<NUM> hrs/<NUM>□C/<NUM>-<NUM>% RH using the inverted cup method as described in <CIT>.

Different portions of the dressing may include different adhesives, such as disclosed in <CIT> titled "Medical Dressing with Multiple Adhesives. " For example, a portion may include an acrylate adhesive while another portion may include a silicone adhesive. In one embodiment, to prevent edge separation, adjacent the perimeter is acrylate adhesive, while near the central portion there is silicone adhesive. In one embodiment, to strongly secure with a device or tubing near the central portion there is acrylate adhesive, while near the perimeter in contact with skin is silicone adhesive.

An absorbent material may also be used in conjunction with the medical dressings described herein. An absorbent material may be the same as the wound packing material (described below) or may be a separate element. The absorbent materials can be manufactured of any of a variety of materials including, but not limited to, woven or nonwoven cotton or rayon. Absorbent pad is useful for containing a number of substances, optionally including antimicrobial agents, drugs for transdermal drug delivery, chemical indicators to monitor hormones or other substances in a patient, etc..

The absorbent may include a hydrocolloid composition, including the hydrocolloid compositions described in <CIT> and <CIT>. The hydrocolloid absorbent may comprise, for example, a natural hydrocolloid, such as pectin, gelatin, or carboxymethylcellulose (CMC) (Aqualon Corp. , Wilmington, Del. ), a semi-synthetic hydrocolloid, such as cross-linked carboxymethylcellulose (X4ink CMC) (e.g. Ac-Di-Sol; FMC Corp. , Philadelphia, Pa. ), a synthetic hydrocolloid, such as cross-linked polyacrylic acid (PAA) (e.g., CARBOPOL™ No. 974P; B. Goodrich, Brecksville, Ohio), or a combination thereof. Absorbent materials may also be chosen from other synthetic and natural hydrophilic materials including polymer gels and foams.

An optional release liners may be included that covers all or a portion of the adhesives to prevent contamination of the adhesives. In one embodiment, the package that contains the adhesive dressing may serve as a release liner. Suitable release liners can be made of kraft papers, polyethylene, polypropylene, polyester or composites of any of these materials. In one embodiment, the liners are coated with release agents such as fluorochemicals or silicones. For example, <CIT> describes low surface energy perfluorochemical liners. In one embodiment, the liners are papers, polyolefin films, or polyester films coated with silicone release materials.

An optional carrier may be included that covers all or a portion of the first major surface of the substrate, providing structural support if the dressing is thin and highly flexible. The carrier maybe removable from the first major surface once the adhesive dressing is placed on skin. The carrier can be constructed of a variety of materials such as fabric that are woven or kitted, nonwoven material, papers, or film. In one embodiment, the carrier is along the perimeter of the first major surface of the dressing and is removable from the first major surface, similar to the carrier used the <NUM> Tegaderm™ Transparent Film Dressing, available from <NUM> Company, St.

Claim 1:
A medical dressing (<NUM>, <NUM>) comprising:
a first major surface (<NUM>), second major surface (<NUM>), opposite the first major surface (<NUM>), and a perimeter (<NUM>), wherein the second major surface (<NUM>) comprises an adhesive (<NUM>);
a backing layer (<NUM>) that is elastic;
a support material (<NUM>) secured to the backing layer (<NUM>) that is less elastic than the backing layer (<NUM>);
a plurality of slits (<NUM>) through the support material (<NUM>), wherein each slit is a long narrow through cut that does not result in removal of support material (<NUM>) and wherein each slit is spaced from an adjacent slit.