Cerebral oximetry provides early warning of oxygen delivery failure during cardiopulmonary bypass

Abstract

EAR-INFRARED spectroscopy has become a well-established technology for oxygen saturation monitoring during cardiac and vascular surgery. It is the basis for not only pulse oximetry,but also continuous mixed venous and jugular bulb oximetry. Although these monitors offer valuable information on oxygen balance,each has important limitations. Pulse oximetry becomes unreliable with nonpulsatile perfusion. Mixed venous oximetry,representing an average of many vascular beds,is relatively insensitive to cerebral hypoxia. Because jugular bulb oximetry measures the entire cranial venous effluent,early indication of cerebral hypoxia primarily affecting the brain regions with the highest metabolic demand may go unnoticed. This case report describes the beneficial use of the newest form of near-infrared spectroscopy,cerebral oximetry, during cardiopulmonary bypass (CPB). Continuous noninvasive transcranial monitoring of brain oxygen balance,assisted by electroencephalogram (EEG) and transcranial Doppler ultrasound,led to the rapid detection and correction of an oxygen delivery failure. CASE REPORT