Cerebral oxygenation measurements
After performing basic monitoring, non-invasive cerebral oxygenation sensors were applied bilaterally to both sides of the forehead (near the frontotemporal hairline and avoiding the frontal sinus) after cleansing the skin with facial scrub. Monitoring of cerebral oxygenation was initiated before the induction of general anesthesia. During surgery, cerebral oxygenation was monitored continuously using the FORE-SIGHT system (CAS Medical Systems, US) under the supervision of the attending anesthesiologist. The regional oximetry device used NIRS to measure the oxygen saturation of hemoglobin in the local brain tissue and displayed both absolute and trend rSO