What Does the Photoplethysmography Add to Laser Doppler Flowmetry During the Brachial Artery Occlusion Test?

In this study, the difference in behavior of the raw photoplethysmography (PPG) signal and the laser Doppler flowmetry (LDF) signal reflecting hemodynamics in the skin of upper extremities at brachial arterial occlusion is recorded and discussed. It is shown that at various locations on the hand, the raw PPG signal provides richer and previously little-known information on the redistribution of blood between the arterial, microcirculatory, and venous beds, while the conventional blood flow (BF) parameter recorded by LDF technique is less sensitive to it and largely does not capture this redistribution.