Monitoring brain hemoglobin oxygenation in per-operatory conditions through near infra-red absorbance measurements

A near infra-red absorbance meter designed to monitor haemoglobin oxygenation at two wavelength on adult skulls in per-operatory conditions of noise and illumination is presented in this paper, together with examples of records on volunteers. The absorbance variations due to apnea or oxygen enriched gaz mixtures are clearly detectable. The total blood content of the examined volume is simultaneously measured through this technique.