- This study aimed to investigate the impact of posture and anesthesia techniques on blood pressure changes, heart rate and regional cerebral oxygen saturation during shoulder arthroscopy in the beach chair position (BCP). Sixty patients were included in this prospective cohort study: 30 patients mechanically ventilated and subjected to general anesthesia (GA) and 30 patients subjected to interscalene block (ISB) without mechanical ventilation. Noninvasive blood pressure, heart rate (HR), peripheral blood oxygen saturation and regional oxygen saturation of the brain were measured in twelve predefined points during perioperative period. The GA group patients had significantly lower mean arterial pressure and heart rate values compared to patients in ISB group during BCP (p<0.001). There was a significant difference in regional cerebral saturation between the groups measured only in points of induction and emergence from anesthesia in favor of GA group when receiving 100% oxygen (p<0.001). Changes in the mean arterial pressure and regional cerebral oxygen saturation for both brain hemispheres correlated only at the 10 minute after setting up BCP in GA patients (right, p=0.004 and left, p=0.003). This correlation did not exist in the ISB group patients at any of the points measured. Cerebral desaturation events recorded in both groups were not statistically significantly different. Results of this study demonstrated that GA preserved regional cerebral oxygenation in a safe range during BCP despite changes in the arterial blood pressure and heart rate in comparison to ISB.