Adaptable surface for use in beds and chairs to reduce occurrence of pressure ulcers

Abstract

An adaptable surface system including a plurality of individually adjustable surface units and a plurality of pressure sensors. Each pressure sensor corresponds to one of the adjustable subsurface units and is positioned to measure an amount of pressure exerted upon the subsurface unit. The system also includes a controller that receives a first pressure value from a pressure sensor, compares the value to a threshold, and adjusts the height of the first subsurface unit based on the comparison. The controller also receives a second pressure value from a second pressure sensor, compares the second pressure value to the threshold, and adjusts the height of a second subsurface unit based on the comparison.

I claim: 
     
         1 . An adaptable surface system comprising:
 a surface including a plurality of individually adjustable subsurface units;   a plurality of subsurface pressure sensors, each pressure sensor of the plurality of subsurface pressure sensors corresponding to one of the plurality of individually adjustable subsurface units and positioned to measure an amount of pressure exerted upon the corresponding subsurface unit;   a controller including a processor and a computer readable memory storing computer instruction that, when executed by the processor, cause the controller to:
 receive a first pressure value from a first subsurface pressure sensor of the plurality of subsurface pressure sensors, the first subsurface pressure sensor corresponding to a first subsurface unit, 
 compare the first pressure value to a threshold, 
 adjust a height of a first subsurface unit relative to the surface based upon the comparison of the first pressure value and the threshold, 
 receive a second pressure value from a second subsurface pressure sensor of the plurality of subsurface pressure sensors, the second subsurface pressure sensor corresponding to a second subsurface unit, 
 compare the second pressure value to the threshold, and. 
 adjust a height of a second subsurface unit relative to the surface based upon the comparison of the second pressure value and the threshold. 
   
     
     
         2 . The adaptable surface system of  claim 1 , wherein the surface includes a vertical surface and the controller adjusts the height of the first subsurface unit by causing the first subsurface unit to move horizontally relative to the surface. 
     
     
         3 . The adaptable surface system of  claim 1  further comprising a bed, and wherein the surface includes a mattress of the bed. 
     
     
         4 . The adaptable surface system of  claim 1  further comprising an air pump, and wherein each of the plurality of subsurface units includes an inflatable bladder and a valve coupled to the air pump. 
     
     
         5 . The adaptable surface system of  claim 4 , wherein the controller adjusts the height of the first subsurface unit by opening the valve of the first subsurface unit causing air from the air pump to inflate the inflatable bladder. 
     
     
         6 . The adaptable surface system of  claim 4 , wherein the controller adjusts the height of the first subsurface unit by closing the valve of the first subsurface unit and preventing air from being pumped into the inflatable bladder. 
     
     
         7 . The adaptable surface system of  claim 1 , wherein each of the plurality of subsurface units includes an inflatable bladder and a valve positioned to allow air to escape the inflatable bladder. 
     
     
         8 . The adaptable surface system of  claim 7 , wherein the controller adjusts the height of the first subsurface unit by opening the valve and allowing air to escape from the inflatable bladder. 
     
     
         9 . The adaptable surface system of  claim 1 , wherein each of the plurality of subsurface units includes a motor coupled to a pin, and wherein the controller adjusts the height of the first subsurface unit by causing the motor to change a position of the pin relative to the surface. 
     
     
         10 . The adaptable surface system of  claim 1 , wherein the controller adjusts the height of the first subsurface unit based upon the comparison of the first pressure value and the threshold by lowering the height of the first subsurface unit if the first pressure value exceeds the threshold. 
     
     
         11 . The adaptable surface system of  claim 10 , wherein the controller further calculates an adjustment value proportional to a difference between the first pressure value and the threshold and lowers the height of the first subsurface unit according to the adjustment value. 
     
     
         12 . The adaptable surface system of  claim 1 , wherein, after adjusting the height of the first subsurface unit, the controller
 receives a second first pressure value from the first subsurface pressure sensor,   compares the second first pressure value to the threshold, and   adjusts the height of the first subsurface unit relative to the surface based upon the comparison of the second first pressure value and the threshold.   
     
     
         13 . The adaptable surface system of  claim 1 , wherein the controller compares the first pressure value to a range of pressure values, the threshold being within the range, and wherein the controller does not change the height of the first subsurface unit when the first pressure value is within the range of pressure values. 
     
     
         14 . The adaptable surface system of  claim 1  further comprising a pressure sensor array wherein each of the plurality of subsurface pressure sensors includes one or more of the pressure sensors in the pressure sensor array. 
     
     
         15 . The adaptable surface system of  claim 1 , wherein the plurality of subsurface units are modularly connected so that at least one of the plurality of subsurface units can be removed from the adaptable surface system while the controller continues to operate. 
     
     
         16 . The adaptable surface system of  claim 1  further comprising a sensor positioner, the sensor positioner being movable across the surface and exerting a pressure on the surface such that when the sensor positioner is positioned on the first subsurface, the pressure is detected by the first subsurface pressure sensor and the height of the first subsurface is adjusted. 
     
     
         17 . The adaptable surface system of  claim 16 , wherein the sensor positioner includes a sensor to measure a condition of a subject supported by the surface. 
     
     
         18 . A hospital bed that adapts to the pressure exerted upon a mattress by a subject supported by the mattress, the hospital bed comprising:
 a mattress including an array of individually adjustable subsurface units;   a plurality of pressure sensor positioned to measure pressure exerted upon each of the subsurface units in the array;   a controller including a processor and a computer readable memory, the controller configured to
 receive a plurality of pressure values from each of the plurality of subsurface pressure sensors at regular time intervals, 
 determine when a pressure value corresponding to one of the subsurface units is outside of a defined range, and 
 generate at least one command signal to adjust a height of the one of the subsurface units relative to the mattress when the pressure value is outside of the defined range. 
   
     
     
         19 . The hospital bed of  claim 18 , wherein the computer readable memory stores the defined range. 
     
     
         20 . The hospital bed of  claim 18 , wherein the control is further configured to calculate the defined range based upon a total amount of pressure exerted upon the mattress. 
     
     
         21 . The hospital bed of  claim 18 , wherein the defined range includes all pressure values below a threshold and wherein the controller is further configured to cause the controller to lower the height of one of the subsurface units when the received pressure value from the corresponding pressure sensor exceeds the threshold. 
     
     
         22 . The hospital bed of  claim 18 , wherein the controller is further configured to cause the controller to lower the height of one of the subsurface units when the received pressure value from the corresponding pressure sensor is above the defined range and to raise the height of the one of the subsurface units when the received pressure value from the corresponding pressure sensor is below the defined range. 
     
     
         23 . The hospital bed of  claim 18  further comprising a mattress housing and a sensor positioner, wherein the sensor positioner is coupled to the mattress housing and movable relative to the mattress, and wherein the sensor positioner exerts force on one or more subsurface units when the sensor positioner is moved across the mattress causing the controller to adjust the height of the one or more subsurface units. 
     
     
         24 . The hospital bed of  claim 23 , wherein the sensor positioner further includes a connector for holding one or more interchangeable sensors. 
     
     
         25 . The hospital bed of  claim 23 , wherein the sensor positioner includes a connector for holding one or more interchangeable cleaning tools. 
     
     
         26 . The hospital bed of  claim 25  further comprising a water-tight cover that is selectively positionable over the mattress housing.