Continuous, noninvasive measurement of cytochrome oxidase in cerebral cortex by near-infrared spectrophotometry during aortic arch surgery

The incidence of neurological dysfunction after cardiac surgery or thoracic aortic surgery with cardiopulmonary bypass (CPB) is much higher than after general surgery [1,2]. To prevent neurological complications, it is important to detect any deterioration in cerebral function and oxygenation as early as possible in the perioperative period. Accordingly, we noninvasively and continuously monitored changes in hemoglobin oxygenation and in the redox state of cytochrome oxidase (Cyt.aa3) in the cerebral cortex by near-infrared spectrophotometry (NIRS) during aortic arch surgery, and evaluated whether or not the level of reduced Cyt.aa3 could be used as a real-time indicator of any neurological prognosis.