Spatial and temporal variation in laser Doppler flux values in healthy lower limbs: comparison between the standard and the multiprobe.

Skin flow recordings with a laser Doppler instrument have not proven useful for evaluation of patients with peripheral arterial occlusive disease. The introduction of a probe using seven fibers suggested a reduction in spatial variation, but few studies using this multiprobe have been published. The present study was designed to compare the multiprobe to the standard probe placed between the knee and the first toe, chosen to fit a future study for amputation levels. The aim was to evaluate the multiprobe for that purpose. A laser Doppler fluxmeter with a standard and a multiprobe was used. Measurements were made in five probe sites in lower limbs of healthy volunteers. Each subject was studied by 30-second recordings during 60 min with both probes. Statistically (p < 0.001) lower flux values were obtained with the multiprobe than with the standard probe. The flux variation between the five probe sites was significantly (p < 0.01) higher with the standard probe than with the multiprobe, but the temporal variation was similar with both probes. The results suggest that the spatial variation in widely separated probe sites is reduced with the multiprobe. The temporal variation was not found to be reduced.