Influence of Beach Chair Position on Cerebral Oxygen Saturation: A Comparison of INVOS and FORESIGHT Cerebral Oximeter

Background: Although beach chair position (BCP) is frequently used for shoulder surgery, a potentially detrimental influence on cerebral oxygenation is discussed. Therefore, the present study investigated changes in regional cerebral oxygen saturation (rSO sub(2)/StO sub(2)) during BCP comparing 2 different devices for near-infrared spectroscopy measurement. Methods: Data were collected in 35 patients undergoing shoulder surgery in BCP and compared with a control group of 35 awake volunteers. The rSO sub(2)/StO sub(2) was assessed using INVOS and FORE-SIGHT monitors. Mean arterial blood pressure (MAP), peripheral oxygen saturation (SpO sub(2)), PeCO sub(2), FiO sub(2), end-tidal sevoflurane concentration, and rSO sub(2)/StO sub(2) were measured before positioning, during BCP, and in supine position after surgery. Results: A decrease in rSO sub(2)/StO sub(2) could be observed after BCP (INVOS: 76.1% supine vs. 66.7% BCP, P