The safety of controlled hypotension for shoulder arthroscopy in the beach-chair position

Background: The safety of controlled hypotension during arthroscopic shoulder procedures with the patient in the beachchair position is controversial. Current practice for the management of intraoperative blood pressure is derived from expert opinion among anesthesiologists, but there is a paucity of clinical data validating their practice. The purpose of this study was to evaluate the effect of controlled hypotension on cerebral perfusion with use of continuous electroencephalographic monitoring in patients undergoing shoulder arthroscopy in the beach-chair position. Methods: Fifty-two consecutive patients who had undergone shoulder arthroscopy in the beach-chair position were enrolled prospectively in this study. All patients underwent preoperative blood pressure measurements, assignment of an American Society of Anesthesiologists (ASA) grade, and a preoperative and postoperative neurological and Mini-Mental State Examination (MMSE). The target systolic blood pressure for all patients was 90 to 100 mm Hg during surgery. Continuous intraoperative monitoring was performed with standard ASA monitors and a ten-lead portable electroencephalography monitor. Real-time electroencephalographic monitoring was performed by an attending-level neurophysiologist. Results: All patients violated at least one recommended limit for blood pressure reduction. The average decrease in systolic blood pressure and mean arterial pressure from baseline was 36% and 42%, respectively. Three patients demonstrated ischemic changes on electroencephalography that resolved with an increase in blood pressure. No adverse neurological sequelae were observed in any patient on the basis of the MMSE. Conclusions: This study provides the first prospective data on global cerebral perfusion during shoulder arthroscopy in the beach-chair position with use of controlled hypotension. Our study suggests that patients may be able to safely tolerate a reduction in blood pressure greater than current recommendations. In the future, intraoperative cerebralmonitoringmay play a role in preventing neurological injury in patients undergoing shoulder arthroscopy in the beach-chair position.