Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors

Study Objectives To evaluate changes in cerebral tissue oxygen index (TOI) values under the beach chair position before and during general anesthesia in surgical patients with or without cardiovascular risk factors. Design Prospective study. Setting Operating room in the university hospital. Patients Ninety-one patients undergoing surgery, including healthy patients (n = 28), patients with 1 cardiovascular risk factor (n = 33), and those with more than 1 risk factor (n = 30). Interventions and Measurements Cerebral TOI the day before and during general anesthesia was evaluated using a near-infrared spectroscopy NIRO-200 (Hamamatsu Photonics, Hamamatsu, Japan) for each patient. The initial TOI measurement in the supine position after a 10-minute rest or 10 minute after the endotracheal intubation was followed by measurements in 30° and subsequent 60° upright position for 5 minutes. Phenylephrine 0.1 mg and/or ephedrine 4 mg was administered intravenously to maintain mean blood pressure above 60 mm Hg accordingly. Main Results The beach chair position decreased mean arterial blood pressure and heart rate under general anesthesia, although patients with more than 1 cardiovascular risk factor needed significantly more phenylephrine doses to maintain mean blood pressure above 60 mm Hg. Values of TOI were within the normal range of about 70% before and during anesthesia in all groups. Conclusions The beach chair position under general anesthesia did not alter cerebral oxygenation in patients with or without cardiovascular risk factors showing normal preoperative cerebral TOI values when the mean blood pressure was maintained above 60 mm Hg. The careful management using the cerebral oxygenation monitoring appears to maintain cerebral perfusion in the beach chair position during general anesthesia.