The measurement of cutaneous blood flow in healthy volunteers subjected to physical exercise with ultrasound Doppler imaging and laser Doppler flowmetry

Abstract

We aimed to evaluate hemodynamic parameters in the cutaneous microcirculation during recovery to graded dynamic exercise performed on a cycloergometer by using two distinctive methods: high-frequency ultrasound Doppler flowmetry (UDF) and laser Doppler fluxmetry (LDF). Regarding UDF, the medium linear blood flow velocity (V_am) was estimated, expressed in absolute units (cm/s) whereas blood flow assessed by LDF was registered in arbitrary perfusion units (PU). We compared the corresponding perfusion values obtained by UDF and LDF, respectively, every 20 s during recovery period to physical exercise. Three types of microvascular blood flow dynamics were recorded: blood flow with an occasional paroxysm, a pulsatile blood flow pattern, and a shunting-type blood flow pattern. In the first type, the reaction time of registration and the direction of changes of UDF and LDF values coincided in 77.7%, exhibiting high correlation (r = 0.77; p≤0.001). In the second type, the direction of changes of UDF and LDF showed 85.0% similarity and a moderate correlation (r = 0.66; p = 0.0015), whereas in the third type, there was also a moderate correlation (r = 0.53, p = 0.0024). Our pilot experiments have shown that UDF could be regarded as a comparable substitutional method to LDF for studying skin microcirculation.