MEASUREMENT OF VENOUS OXYHEMOGLOBIN SATURATION IN THE ADULT HUMAN FOREARM BY NEAR-INFRARED SPECTROSCOPY WITH VENOUS OCCLUSION

Measurement of the oxygenation of the peripheral tissues provides usef ul information about tissue perfusion. A method is described for the-m easurement of peripheral venous oxyhaemaglobin saturation (SvO(2)) in the adult forearm by a noninvasive technique, near infrared spectrosco py (NIRS) with venous occlusion. A senses of studies is performed on h ealthy adults to compare measurements of forearm SvO(2) made by NIRS w ith measurements of superficial venous SvO(2) made by co-oximetry, and to study the effect of different optode spacings. There is a signific ant correlation between forearm SvO(2) measured by NIRS and SvO(2) of superficial venous blood measured by co-oximetry (n=19, r=0.7, p<0.000 1). Higher values for SvO(2) were obtained using a 2.5 cm spacing than with a 4 cm spacing (mean difference=4.1% (95% CI 1.4%-6.8%) n=16). T his difference is likely to have been due to a more superficial volume of tissue being studied with the closer optode spacing. Peripheral Sv O(2) can-be measured noninvasively using NIRS with venous occlusion. I t may prove to be a useful method to study circulatory disturbances.