Wound therapy device pressure monitoring and control system

Abstract

A new system for negative pressure wound therapy is described. The system includes a patient tube set connecting the wound dressing to the suction container. The patient tube set provides separate channels for applying suction to the wound site and sensing the therapeutic pressure at the wound site. A restrictor valve may also be included in order to introduce a small air leak into the system to prevent occlusions in the patient tube set.

What is claimed is: 
     
         1 . A wound therapy system comprising:
 a wound dressing;   a pressure sensor;   a container having an internal chamber;   a vacuum source pneumatically associated with the internal chamber of the container; and   a tube set comprising a first tube and a second tube positioned inside a lumen of the first tube, wherein a space between the first tube and the second tube forms a fluid channel, and wherein a lumen of the second tube forms a sensor channel in the tube set;   wherein the wound dressing is pneumatically associated with the internal chamber of the container by the fluid channel of the tube set;   wherein the wound dressing is pneumatically associated with the pressure sensor by the sensor channel of the tube set; and   wherein a crushing force required to occlude the fluid channel is greater than a crushing force required to occlude a fluid channel of a comparison tube set that does not include a second tube positioned inside a lumen of the first tube.   
     
     
         2 . The wound therapy system of  claim 1 , wherein the fluid channel and the sensor channel of the tube set are formed by a first tube and a second tube. 
     
     
         3 . The wound therapy system of  claim 2 , wherein the second tube is formed within the first tube,
 wherein the sensor channel is a lumen of the second tube, and   wherein the fluid channel is a space between the first tube and second tube.   
     
     
         4 . The wound therapy system of  claim 2 , wherein the container has a first port comprising a first attachment and a second attachment;
 wherein a first end of the first tube is coupled to the wound dressing and a second end of the first tube is coupled to the first attachment of the first port; and   wherein a first end of the second tube connects to the wound dressing and a second end of the second tube connects to the second attachment of the first port.   
     
     
         5 . The wound therapy system of  claim 4 , wherein the container further comprises a second port and a sensor tube, wherein a first end of the sensor tube is connected to the second attachment of the first port and the second end of the sensor tube is connected to the second port, and wherein the pressure sensor is pneumatically associated with the second port on the container. 
     
     
         6 . The wound therapy system of  claim 4 , further comprising an adapter that couples the second end of the first tube to the first attachment of the first port and the second end of the second tube to the second attachment of the first port. 
     
     
         7 . The wound therapy system of  claim 4 , wherein the wound dressing is a first wound dressing, and wherein the wound therapy system further comprises a second wound dressing and a y-connector,
 wherein a first port of the y-connector is pneumatically associated with the first port of the container, wherein a second port of the y-connector is pneumatically associated with the first wound dressing, and wherein a third port of the y-connector is pneumatically associated with the second wound dressing.   
     
     
         8 . The wound therapy system of  claim 1 , wherein the fluid channel and the sensor channel are pneumatically associated with one another at the wound dressing. 
     
     
         9 . The wound therapy system of  claim 1 , further comprising a pressure sensor pneumatically associated with the vacuum source. 
     
     
         10 . The wound therapy system of  claim 1 , further comprising a restrictor pneumatically associated with the wound dressing by the sensor channel of the patient tube, wherein the restrictor has a hole that is configured to allow air to leak into the wound therapy system. 
     
     
         11 . The wound therapy system of  claim 10 , wherein the restrictor comprises:
 a body having a first port and a second port;   a cap coupled to the first port of the body, the cap having a hole; and   a porous material positioned between the cap and the first port of the body;   wherein air is configured to enter the device through the hole in the cap and pass through the porous material before entering the first port of the body.   
     
     
         12 . The wound therapy system of  claim 11 , wherein the restrictor is adjustable, and wherein tightening a connection between the cap and the body compresses the porous material and decreases a rate of airflow across the porous material. 
     
     
         13 . The wound therapy system of  claim 10 , wherein the restrictor leaks air into the system at a rate of about 0.05-0.1 liters per minute when the vacuum source applies a vacuum to the system. 
     
     
         14 . The wound therapy system of  claim 10 , wherein vacuum source is configured to compensate for air leaking into the system such that the pressure at the wound dressing is not substantially altered. 
     
     
         15 . The wound therapy system of  claim 1 , wherein the sensor channel has a cross-sectional area of at least 0.75 mm 2 . 
     
     
         16 . The wound therapy system of  claim 1 , wherein the tube set comprises exactly one sensor channel. 
     
     
         17 . The wound therapy system of  claim 1 , wherein the tube set comprises a plurality of sensor channels. 
     
     
         18 . The wound therapy system of  claim 1 , wherein the tube set is a first tube set, and wherein the wound therapy system further comprises a second tube set having a fluid channel and a sensor channel, and a valve positioned in-line between the first tube set and the second tube set. 
     
     
         19 . The wound therapy system of  claim 18 , wherein the valve has an open position and a closed position;
 wherein the valve, when in the open position, allows communication between the fluid channel of the first tube set and the fluid channel of the second tube set, and also allows communication between the sensor channel of the first tube set and the sensor channel of the second tube set; and   wherein the valve, when in the closed position, blocks communication between the fluid channel of the first tube set and the fluid channel of the second tube set, and also blocks communication between the sensor channel of the first tube set and the sensor channel of the second tube set.   
     
     
         20 . The wound therapy system of  claim 1 , wherein the first tube and the second tube are able to maintain their shape when a vacuum is applied by the vacuum source. 
     
     
         21 . The wound therapy system of  claim 1 , wherein the fluid channel is substantially unobstructed. 
     
     
         22 . A method of wound therapy comprising:
 applying a dressing to a wound, wherein the dressing is coupled to a tube set comprising a fluid channel and a sensor channel;   applying a vacuum to the fluid channel, wherein the vacuum draws exudate from the wound into the fluid channel; and   providing a restrictor pneumatically associated with the wound dressing by the sensor channel, the restrictor having a hole through which air can leak into the sensor channel, wherein the air pushes fluids from the wound dressing into the fluid channel of the tube set.   
     
     
         23 . The method of  claim 22 , wherein the step of applying the vacuum to the fluid channel allows air to continuously leak from the restrictor into the sensor channel. 
     
     
         24 . The method of  claim 22 , further comprising a step of opening the restrictor intermittently to allow air to leak into the sensor channel when the restrictor is open. 
     
     
         25 . The method of  claim 24 , wherein the restrictor is a solenoid. 
     
     
         26 . The method of  claim 22 , further comprising:
 measuring a therapeutic pressure at the dressing using a pressure sensor connected to the sensor channel; and   adjusting the pressure of the vacuum applied to the fluid channel based on the therapeutic pressure measured by the pressure sensor.   
     
     
         27 . The method of  claim 22 , further comprising a step of forming the tube set such that the tube set comprises an inner tube and an outer tube, wherein the sensor channel is a lumen of the inner tube, and wherein the fluid channel is a space between the outer tube and inner tube. 
     
     
         28 . The method of  claim 22 , further comprising a step of adjusting the restrictor to change the rate at which air leaks into the system. 
     
     
         29 . A device for creating an air leak, the device comprising:
 a body having a first port in communication with a second port;   a cap coupled to the first port of the body, the cap having a hole; and   a porous material positioned between the cap and the first port of the body;   wherein air is configured to enter the device through the hole in the cap and pass through the porous material before entering the body via the first port.   
     
     
         30 . The device of  claim 29 , wherein tightening a connection between the cap and the body compresses the porous material and decreases a rate of airflow across the porous material. 
     
     
         31 . The device of  claim 29 , wherein the device is configured to allow air to flow out of the second port at a rate of 0.05-0.1 liters per minute.