Blood flow and oxygen consumption with near-infrared spectroscopy and venous occlusion: spatial maps and the effect of time and pressure of inflation

We have measured the local blood flow (BF) and oxygen consumption (OC) in t he human calf muscle using near-infrared spectroscopy during venous occlusi on. Venous occlusion was achieved by inflating a pneumatic cuff around the thigh of the subject. We have investigated the influence of the inflation r ime and cuff pressure on the recovered values of BF and OC. We have found t hat if the cuff pressure is increased from a threshold pressure (similar to 30 mm Hg) to a critical pressure (similar to 45 mm Hg) in less than about 6 s, one measures the same values of BF and OC independent of the total inf lation time and final cuff pressure. We also report nine-pixel spatial maps of BF and OC to show that this technique can lead to spatially resolved me asurements of blood flow and oxygen consumption in tissues. (C) 2000 Societ y of Photo-Optical instrumentation Engineers. [S1083-3668(00)00903-5].