Noninvasive measurement of forearm blood flow and oxygen consumption by near-infrared spectroscopy.

We applied near-infrared spectroscopy (NIRS) for the simultaneous measurement of forearm blood flow (FBF) and oxygen consumption (VO2) in the human by inducing a 50-mmHg venous occlusion. Eleven healthy subjects were studied both at rest and after hand exercise during vascular occlusion. FBF was also measured by strain-gauge plethysmography. FBF measured by NIRS was 1.9 +/- 0.8 ml.100 ml-1.min-1 at rest and 8.2 +/- 2.9 ml.100 ml-1.min-1 after hand exercise. These values showed a correlation (r = 0.94) with those obtained by the plethysmography. VO2 values were 4.6 +/- 1.3 microM O2 x 100 ml-1.min-1 at rest and 24.9 +/- 11.2 microM O2 x 100 ml-1.min-1 after hand exercise. The scatter of the FBF and VO2 values showed a good correlation between the two variables (r = 0.93). The results demonstrate that NIRS provides the particular advantage of obtaining the contemporary evaluation of blood flow and VO2, allowing correlation of these two variables by a single maneuver without discomfort for the subject.