Negative pressure assisted tissue treatment system

Abstract

A system for stimulating the healing of tissue comprises a porous pad positioned within a wound cavity, and an airtight dressing secured over the pad, so as to provide an airtight seal to the wound cavity. A proximal end of a conduit is connectable to the dressing. A distal end of the conduit is connectable to a negative pressure source, which may be an electric pump housed within a portable housing, or wall suction. A canister is positioned along the conduit to retain exudates suctioned from the wound site during the application of negative pressure. A first hydrophobic filter is positioned at an opening of the canister to detect a canister full condition. A second hydrophobic filter is positioned between the first filter and the negative pressure source to prevent contamination of the non-disposable portion of the system by exudates being drawn from the wound. An odor filter is positioned between the first and second hydrophobic filters to aid in the reduction of malodorous vapors. A securing means is supplied to allow the portable housing to be secured to a stationary object, such as a bed rail or intravenous fluid support pole. A means for automated oscillation of pressure over time is provided to further enhance and stimulate the healing of an open wound. A means for varying pump drive frequency and a means for managing a portable power supply are provided to increase battery life and improve patient mobility.

1 . A system for stimulating healing of tissue at a wound site comprising:
 a porous pad;   a pump for delivering an actual pressure to apply as negative pressure to the wound site through said porous pad; and   a controller for varying the negative pressure by determining whether the actual pressure is increasing or decreasing and comparing the actual pressure to a target pressure and, when the actual pressure has equaled the target pressure, moving the target pressure toward (a) a maximum target pressure if the actual pressure is increasing, or (b) a minimum target pressure if the actual pressure is decreasing.   
     
     
         2 . The system of  claim 1 , wherein the controller moves the target pressure by incrementing the target pressure toward the maximum target pressure when the actual pressure is increasing and equal to or greater than the target pressure. 
     
     
         3 . The system of  claim 2 , wherein the actual pressure is increasing and said controller is adapted to compare the target pressure to the maximum target pressure and begin decreasing the actual pressure when the target pressure is equal to or greater than the maximum target pressure. 
     
     
         4 . The system of  claim 3 , wherein said controller is further adapted to decrement the target pressure toward the minimum target pressure when the actual pressure is equal to or less than the target pressure. 
     
     
         5 . The system of  claim 4 , wherein said controller is further adapted to compare the target pressure to the minimum target pressure and begin increasing the actual pressure when the target pressure is equal to or less than the minimum target pressure, whereby the negative pressure oscillates over time between the maximum target pressure and the minimum target pressure. 
     
     
         6 . The system of  claim 1 , wherein the controller decrements the target pressure toward the minimum target pressure when the actual pressure is decreasing and equal to or less than the target pressure. 
     
     
         7 . The system of  claim 6 , wherein the actual pressure is decreasing and said controller is adapted to compare the target pressure to the minimum target pressure and begin increasing the actual pressure when the target pressure is equal to or less than the minimum target pressure. 
     
     
         8 . The system of  claim 7 , wherein said controller is further adapted to increment the target pressure toward the maximum target pressure when the actual pressure is equal to or greater than the target pressure. 
     
     
         9 . The system of  claim 8 , wherein said controller is further adapted to compare the variable target pressure to the maximum target pressure and begin decreasing the actual pressure when the target pressure is equal to or greater than the maximum target pressure, whereby the negative pressure oscillates over time between the maximum target pressure and the minimum target pressure. 
     
     
         10 . A system for stimulating healing of tissue at a wound site comprising:
 a porous pad;   a pump for delivering an actual pressure to apply as negative pressure to the wound site through said porous pad; and   a controller for varying the negative pressure by comparing the actual pressure to a target pressure and, (a) if the actual pressure is increasing, incrementing the target pressure toward a maximum target pressure when the actual pressure is equal to or greater than the target pressure, or (b) if the actual pressure is decreasing, decrementing the target pressure toward a minimum target pressure when the actual pressure is equal to or less than the target pressure.   
     
     
         11 . The system of  claim 10 , wherein the actual pressure is increasing and said controller is further adapted to compare the target pressure to the maximum target pressure and begin decreasing the actual pressure when the target pressure is equal to or greater than the maximum target pressure. 
     
     
         12 . The system of  claim 10 , wherein the actual pressure is decreasing and said controller is further adapted to compare the target pressure to the minimum target pressure and begin increasing the actual pressure when the target pressure is equal to or less than the minimum target pressure. 
     
     
         13 . The system of  claim 10 , wherein said controller further adapted to decrease the actual pressure when the target pressure is equal to or greater than the maximum target pressure and increase the actual pressure when the target pressure is equal to or less than the minimum target pressure, whereby the negative pressure oscillates over time between the maximum target pressure and the minimum target pressure. 
     
     
         14 . A system for stimulating healing of tissue at a wound site comprising:
 a porous pad;   a pump for delivering an actual pressure to apply as negative pressure to the wound site through said porous pad; and   a controller for varying the negative pressure by determining whether the actual pressure is increasing or decreasing and comparing the actual pressure to a target pressure, and (a) if the actual pressure is increasing and equal to or greater than the target pressure, incrementing the target pressure toward a maximum target pressure, or (b) if the actual pressure is decreasing and equal to or less than the target pressure, decrementing the target pressure toward a minimum target pressure.   
     
     
         15 . The system of  claim 14 , wherein said controller is further adapted to (a) begin decreasing the actual pressure when the target pressure is equal to or greater than the maximum target pressure, or (b) begin increasing the actual pressure when the target pressure is equal to or less than the minimum target pressure, whereby the negative pressure oscillates over time between the maximum target pressure and the minimum target pressure.