The relationship of transcutaneous PO2 and laser Doppler measurements in a human model of local arterial insufficiency.

Transcutaneous PO2 and laser Doppler measurements were made over areas of unheated and heated skin of the feet of normal volunteers. Stepwise elevation of the foot above the level of the heart systematically reduced the local arterial pressure and, thus, the local arteriovenous gradient in these areas. Results indicated that transcutaneous PO2 and laser Doppler measurements reflect changes in local arteriovenous gradient when made over areas of warmed skin, but not unwarmed skin. Comparison of skin surface and subcutaneous temperatures obtained with two heater types revealed the importance of heater configuration. Results confirm a previously hypothesized nonlinear relationship between transcutaneous PO2 and local cutaneous blood flow and indicate that a transcutaneous PO2 reading of zero may be obtained in the presence of significant local cutaneous blood flow.