The effect of the beach-chair position angle on cerebral oxygenation during shoulder surgery

Background Although the safety of the beach-chair position (BCP) is widely accepted, rare devastating neurologic complications have been reported and attributed to cerebral hypoperfusion. Cerebral oxygenation (regional oxygen saturation [rSO2 ]) can be monitored noninvasively using near-infrared spectroscopy. The purpose of this study was to determine the effect of BCP angle on cerebral oxygenation in patients undergoing shoulder surgery in the BCP. Methods Fifty patients undergoing shoulder arthroscopy were prospectively enrolled to participate. Following induction of general anesthesia, each patient's rSO2 was recorded at 0° of elevation and again at 30°, 45°, 60°, and 80° of elevation. Mean rSO2 values and mean differences in rSO2 were reported. Results An average total decrease of 5% in rSO2 was seen when comparing 0° with 80° ( P