Partitional measurements of circulation can be made between capillaries and arterovenous anastomoses in the human finger.

Abstract

We compared the responses of finger blood flow to local and/or whole body warming, as measured by laser Doppler flowmetry (PERIFLUX PF-ld) (LDF), and by venous occlusion plethysmography (BF). The subject's hands were immersed in a bath of water whose temperature (TW) was initially set at 25°C. The tested hand was kept at about 10 cm above heart level to facilitate the drainage of finger veins during measurement. The ambient temperature (Ta) was initially 20 C. Then, measurements were made under the following conditions on separate days: 1) local hand warming ony (LHW), Tw was raised from 25 to 40°C; 2) whole body warming only (WBW), Ta was raised from 20 to 35°C; and 3) LHW and WBW combined (CW), LHW (TW was raised to 35°C and maintained) was followed by WBW. Results showed that both LHW and WBW increased LDF and BF. LDF signals correlated significantly with BF values in each condition (r = 0.932-0.955). However, the slope of the line showing the relationship of LDF and BF, determined by least squares linear regression analysis, was steeper in LHW than in WBW. In CW, the slope showed a bend, creating two different sections in the relationship. Below the bend the relation was steeper and showed a similar slope as that in LHW; above the bend, the relation was more gradual and a similar slope as that in WBW. No such bend was observed in measurements of the forearm skin in CW. The present results suggest that partitional measurements of circulation between AVA's and superficial vessels can be made in the finger by the simultaneous use of laser Doppler flowmetry and venous occlusion plethysmography. Local warming of the hand increases finger blood flow mainly through capillaries and subpapillary vessels and indirect whole body warming increases finger blood flow predominantly through deeply located vessels, presumably including AVA's.

Finger cold-induced vasodilation: a review

“…Nagasaka et al (1988) argues that only a minimal part of the AVAs can be ''seen'' by laser Doppler flowmetry using He-Ne lasers. Wollersheim (1988), however, shows that at least part of the shunt flow is included in the laser Doppler results.…”