Time–amplitude analysis of skin blood flow oscillations during the post-occlusive reactive hyperemia in human

The perfusion of forearm skin with blood was studied by the method of laser Doppler flowmetry (LDF) in 94 healthy volunteers. We studied the reaction of the microvascular bed to the transient ischemia, which was initiated by the forearm occlusion. After occlusion, we registered, on average, a 4-fold increase of skin blood perfusion as compared to the level of this parameter at rest. In the study, we also analyzed changes of the oscillatory components of LDF signals during post-occlusive reactive hyperemia; these components were revealed with the adaptive time–amplitude wavelet analysis. It was found that the time needed for oscillations to reach their maximal amplitude is different for each of the frequency intervals examined. After occlusion, a statistically significant rise of the amplitude of blood flow oscillations was revealed—for the frequency intervals corresponding to the cardiac (0.6–2 Hz), respiratory (0.145–0.6 Hz), myogenic (0.052–0.145 Hz), sympathetic (0.021–0.052 Hz), and endothelial (0.0095–0.021 Hz) activity (a more than 11-, 8-, 6-, 3-, and 6-fold increase, respectively, as compared to the state of rest). The method applied here for the analysis of oscillatory components of LDF signals can, therefore, be used to study the dynamics of oscillations of peripheral blood flow under various functional tests.