Cutaneous postocclusive reactive hyperemia monitored by laser doppler flux metering and skin temperature

The initial Laser Doppler Flux (LDF) values and skin temperature in the first, third, and fifth finger were evaluated as well as the postocclusion reactive hyperemia (PORH) response to a 4-min suprasystolic compression. The mean values varied from 276.5 to 335.3 mV while the skin temperature ranged from 32.5 to 34.2 degrees. The LDF-monitored PORH response was very reproducible with an average increase of 144.7 +/- 63.6 mV (from an initial LDF value of 327.1 +/- 134 mV). Four different time-related indices were analyzed: t/2recovery = 6.0 +/- 5.5 sec; trecovery (time to reach the initial value) = 16.7 +/- 11.5 sec; tmax (peak of overshoot) = 48.2 +/- 20.6 sec and t/2 overshoot (time to reach 50% of the tmax on the downslope) = 97.4 +/- 31.8 sec. The simultaneously monitored skin temperature changes lagged significantly behind the LDF changes probably due to the large heat capacitance of the tissue. It is expected that the described results obtained from 20 normal subjects will serve as a basis for future clinical studies involving skin perfusion disorders.