Abstract
In order to have a quantitative evaluation of transcutaneous PO2 (tcPO2) measurement, we have proposed a subcutaneous tissue oxygen transport model. On the steady-state solution of this model, tcPO2 only depends upon the blood flow and the oxygen consumption rate in the subcutaneous tissue, not upon the oxygen diffusion area. The result of the experiment on six healthy adults using tcPO2 electrode at 43°C, called blood interruption stress test, had good similarity to the model. When blood flow was stopped, tcPO2 fell like a straight line with a time delay. And when it was recovered, tcPO2 also recovered exponentially. The linear decrease of tcPO2 on blood flow interruption means that the oxygen consumption rate in subcutaneous tissue does not depend upon oxygen pressure. This finding suggests that the oxygen consumption at the cell level takes place at any oxygen concentration level in its circumstance. From this dynamic response, we could calculate the parameter of this model, and the model suggests that the variety of skin O2 diffusion resistance causes the main error of tcPO2 measurement. These results suggest that this model explains the whole system of tcPO2 measurement.
