Vacuum wound therapy wound dressing with variable performance zones

Abstract

A dressing for an open wound includes a cover layer dimensioned for positioning relative to a wound bed. The cover layer permits an evacuation of the space around the wound bed such that a sub-atmospheric pressure may be established to stimulate healing and facilitate the removal of fluid from the wound. Multiple performance zones in the cover layer allow the wound dressing to remain in position through repeated cycles of evacuation without placing undue strain on the wound bed. An outer peripheral zone may include a high peal-strength adhesive while an intermediate zone may include a shear resistant adhesive. A central zone may be devoid of any coating to maximize moisture transmission through cover layer.

1 . A cover layer for a wound dressing for use in vacuum wound therapy, the cover layer comprising:
 a central zone defined by a portion of a moisture vapor permeable membrane devoid of any coating deterring the transmission of moisture through the membrane;   a peripheral zone substantially surrounding the central zone, the peripheral zone adapted to provide a seal around a perimeter of a wound bed; and   at least one intermediate zone at least partially disposed between the central zone and the peripheral zone, the at least one intermediate zone comprising a substance for imparting a therapeutic effect to the wound bed.   
   
   
       2 . The cover layer according to  claim 1 , wherein the peripheral zone includes a high peal-strength adhesive. 
   
   
       3 . The cover layer according to  claim 1 , wherein the at least one intermediate zone comprises a first intermediate zone including a shear-resistant adhesive 
   
   
       4 . The cover layer according to  claim 3 , wherein the at least one intermediate zone further comprises a second intermediate zone including a medicament delivery coating. 
   
   
       5 . The cover layer according to  claim 3 , wherein the at least one intermediate zone further comprises a second intermediate zone including a hydrogel. 
   
   
       6 . The cover layer according to  claim 3 , wherein the at least one intermediate zone further comprises a second intermediate zone including at least one of an anti-infective agent, an antimicrobial, antibiotic, analgesic, healing factor, vitamins, growth factors, debridement agents, or nutrients. 
   
   
       7 . The cover layer according to  claim 1 , wherein the moisture vapor permeable membrane extends to a periphery of the cover layer to constitute a backing layer, the peripheral zone defined by a layer of adhesive bonded to the backing layer. 
   
   
       8 . The cover layer according to  claim 1 , wherein the peripheral zone and the at least one intermediate zone are arranged concentrically with respect to the central zone. 
   
   
       9 . The cover layer according to  claim 1 , further comprising a port for permitting access to a vacuum reservoir defined under the cover layer for a vacuum tube. 
   
   
       10 . A wound dressing apparatus for use in a vacuum wound therapy procedure, which comprises:
 a contact layer adapted for positioning adjacent a wound bed;   an absorbent filler positioned adjacent the contact layer within the wound bed for collecting liquids exuding from the wound bed;   a cover layer positioned over the wound bed defining a vacuum reservoir there between and permitting access of a vacuum tube to the vacuum reservoir, the cover layer comprising a peripheral zone to provide a seal around the wound bed, at least one intermediate zone for imparting a therapeutic effect to the wound bed, and a central zone formed from a moisture vapor permeable membrane.   
   
   
       11 . The wound dressing apparatus according to  claim 10 , wherein the contact layer is formed from a conical apertured film. 
   
   
       12 . The wound dressing apparatus according to  claim 10 , wherein the absorbent filler material comprises polyolefin filaments arranged in a multi-strand bundle. 
   
   
       13 . The wound dressing apparatus according to  claim 10 , further comprising a vacuum system in fluid communication with the vacuum reservoir. 
   
   
       14 . The wound dressing apparatus according to  claim 13 , wherein the vacuum system includes a vacuum source, a collection canister and a one-way valve.