The effectiveness of cerebral oxygenation monitoring during arthroscopic shoulder surgery in the beach chair position: a randomized blinded study

Beach chair positioning for shoulder surgery is associated with measurable cerebral desaturation events (CDEs) in up to 80% of patients. Near-infrared spectroscopy (NIRS) technology allows real-time measurement of cerebral oxygenation and may minimize the frequency of CDEs. The purpose of this study was to investigate the incidence of CDEs when anesthetists were aware of and blinded to NIRS monitoring and to determine the short-term cognitive effects of surgery in the beach chair position. NIRS was used to monitor cerebral oxygenation saturation in 41 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Patients were randomized to 2 groups, anesthetists aware of or blinded to NIRS data. The Montreal Cognitive Assessment (MoCA) was used to assess cognitive function preoperatively, immediately postoperatively, and at 2 and 6 weeks postoperatively. Overall, 7 (17.5%) patients experienced a CDE, 5 (25%) in the aware group and 2 (10%) in the blinded group. There was no significant difference in MoCA scores between the aware and blinded groups preoperatively (27.9.1 vs. 28.2; P = .436), immediately postoperatively (26.1 vs. 26.2; P = .778), 2 weeks postoperatively (28.0 vs. 28.1; P = .737), or 6 weeks postoperatively (28.5 vs. 28.4; P = .779). There was a correlation of NIRS with systolic blood pressure (r = 0.448), diastolic blood pressure (r = 0.708), and mean arterial pressure (r = 0.608). In our series, the incidence of CDEs was much lower than previously reported and was not lowered by use of NIRS. Patients did not have significant cognitive deficits after arthroscopic surgery in the beach chair position, and there was a correlation between NIRS and intraoperative brachial blood pressure.