The Effects of Alternating Set Pressure Changes on Dynamic Tissue Perfusion Characteristics

The quantitative effectiveness of powered support surfaces such as APAM in preventing and treating pressure ulcers has not been sufficiently evaluated because of uncertainty of alternating pressure load input and lack of interpretation of dynamic perfusion characteristics of soft tissue. The aim was to verify the dynamic loading effects to sacral tissue perfusion characteristics from alternating set pressure changes. We developed integrated experiment system to supply alternating load to supinely positioned sacrum and concurrently measured TcPO2, TcPCO2 and air cell pressure. Ten aged subjects (5 female,5 male) were tested with alternating set pressure 20, 30, 40, 50 and 60mmHg. From the dynamic perfusion response eight characteristic parameters were proposed such as average, minimum, maximum and perfusion range regarding to TcPO2 and TcPCO2. A one-way ANOVA was carried out to determine whether the manipulation of alternating set pressure had any effect on TcPO2 and TcPCO2. From the dynamic tissue perfusion response we found mean TcPO2 decreased exponentially as alternating pressure load increased and perfusion range varied mainly because of minimum level change of TcPO2. And perfusion range of TcPCO2 affected by increase of maximum value of TcPCO2. From the results we can get more strict insights about actual physiological dynamic tissue perfusion mechanism under alternating pressure load