Noninvasive measurement of cerebral hemoglobin oxygen saturation using twonear infrared spectroscopy approaches

Spatially resolved spectroscopy (SRS) is a new near infrared spectroscopy ( NIRS) method that, using the multi-distance approach, measures local cerebr al cortex hemoglobin oxygen saturation [J. Matcher, P. Kirkpatrick, K. Nahi d, M. Cope, and D. T. Delpy, Proc. SPIE 2389, 486-495 (1995)], Using a conv entional continuous wave NIRS photometer, cerebral venous oxygen saturation (SvO(2)) can be calculated from oxyhemoglobin and total hemoglobin rise in duced by partial occlusion of jugular vein [C. E. Elwell, S. J. Matcher, L. Tyszczuk, J. H. Meek, and D. T. Delpy, Adv. Exp. Med. Biol. 411, 453-460 ( 1997)]. The aim of this study was to compare direct measurements of forehea d tissue oxygenation index (TOI) with the calculated SvO(2) during venous o cclusion in 16 adult volunteers using a clinical two-channel SRS oximeter ( NIRO-300). Measured TOI and calculated SvO(2) values of either right or lef t forehead did not significantly differ. A good agreement between the two N IRS methods was also demonstrated. On 16 other subjects, no significant dif ferences were found between the right and left forehead TOI values measured simultaneously, and between the TOI values measured by channel 1 or 2 on t he same side. The results confirm that cerebral cortex hemoglobin oxygen sa turation, measured directly by the SRS method, reflects predominantly the s aturation of the intracranial venous compartment of circulation. (C) 2000 S ociety of Photo-Optical instrumentation Engineers. [S1083-3668(00)00802-9].