The in vivo determination of the blood volume in the foot using a mercury strain gauge plethysmograph and I-131 labelled serum albumin.

Blood volume (cm 3 . 100 cm -3 tissue) measurements were performed in the foot of normal individuals and patients with occlusive arterial disease. The blood volume was estimated by measuring the radioactivity of the foot after the injection of I-131 labelled serum albumin. The calibration of this measurement is performed by comparing the temporary increase in radioactivity during a venous occlusion with the simultaneous volume increase of the foot measured by a mercury strain gauge plethysmograph. The mean blood volume (corrected value) in the foot of normal subjects is not significantly different from the mean corrected value measured in patients with occlusive arterial disease: normal 3.04+/- 0.69 cm3. 100 cm - 3 (n=13), versus pathological 3.23+/- 0.78 cm -3 . 100 cm -3 (n = 14). The measurements of Prerovsky et al on the calf were confirmed with the same technique.