Acute effects and long-term variations in skin blood flow measured with laser Doppler flowmetry

Skin blood flow of 30 healthy volunteers (age 17-58 years) was measured at a number of sites and in different ways using laser Doppler flowmetry (Periflux) to establish reference values. The interindividual and spatial variations were great. The long-term variation in skin blood flow was studied in five subjects from the above group, both at 2-h intervals on the same day and on five different days within 2-3 weeks. No significant variation between the values recorded at different times was observed. Forehead was the best measurement site showing the lowest coefficient of variation (CV) of 20-21%, all mean values recorded at different times falling within the 95% confidence limits of the reference values. Forearm skin blood flow was also followed in another 12 healthy volunteers (age 21-24 years) after administration of 0.5 mg of sublingual nitroglycerin. A rapid and transient increase of about 40% in blood flow, which peaked at 3-4 min was observed (P less than 0.05). It is concluded that laser Doppler flowmetry is very sensitive in measuring acute changes in skin blood flow, and may also be applicable in long-term studies on factors affecting microcirculatory flow.