Laser Doppler resting fluxes, flux motion frequencies and amplitudes at the skin of the dorsum of the foot in healthy young humans.

The complex microvascular geometry and the spatially heterogeneous perfusion of the skin seem to limit the application of Laser Doppler flowmetry (LDF) in resting conditions because of the large spatial variations that these microvascular measurements can show in even very adjacent areas of the dermal mantle. In this study cutaneous LDF was carried out at three spatially different areas of the dorsum of the foot in 22 young (mean age 25.5 years) and healthy human subjects: microvascular resting flux, flux frequency and flux amplitude as well as the distal tissue perfusion pressure as a macrovascular parameter and the skin temperature were measured. Intraindividually marked variations of the microvascular variables often existed between the three areas, but the variability was significantly different (p < 0.001): the resting flux yielded a variation coefficient (VC) of 36.2%, the amplitude of flux waves a VC of 20.2%, while the frequency of flux waves was a very precise individual parameter (VC 7.4%). Interindividually the variation of all three flux parameters was still significantly greater than intraindividually, but the mean value of all the subjects was the same in all three areas: mean resting flux was resp. 2.32, 2.23 and 2.44 arbitrary units (AU); mean frequency of flux waves 5.15, 4.96 and 4.90 cycles min-1; mean amplitude of flux waves 0.34, 0.36 and 0.36 AU. At last, no correlation existed between any of the microvascular flux variables on the one hand and the distal tissue perfusion pressure and skin temperature on the other hand.(ABSTRACT TRUNCATED AT 250 WORDS)