Laser doppler flowmeter measurements of skin perfusion changes associated with arterial and venous compromise in the cutaneous island flap

Laser Doppler flowmetry (LDF) is a noninvasive, continuous measure of tissue surface microcirculatory red blood cell (RBC) flux. LDF was calibrated against varying RBC volume fractions and flow rates using extracorporeal perfusion of saphenous island flaps of dogs. The RBC flux was found to be linear with LDF signal. The difference in vascular geometry of the skin appeared to play a minor role in generating the LDF signal compared to changes in the RBC flux. In vivo experiments of varying arterial perfusion pressure, flap venous pressure, and total blood flow of the cutaneous island flap had a linear relationship with LDF signal.