Cerebral oxygen saturation measured by near-infrared spectroscopy and jugular venous bulb oxygen saturation during arthroscopic shoulder surgery in beach chair position under sevoflurane-nitrous oxide or propofol-remifentanil anesthesia

Abstract

Background: We examined the effects of different anesthetics on cerebral oxygenation and systemic hemodynamics in patients undergoing surgery in beach chair position (BCP). Jugular venous bulb oxygen saturation (SjvO 2) and regional cerebral tissue oxygen saturation (SctO 2) were determined while patients were placed from the supine to BCP. Whether SctO 2 and SjvO 2 are interchangeable in assessing the cerebral oxygenation was also examined. Methods: Forty patients undergoing shoulder surgery in BCP were randomly assigned to receive sevoflurane-nitrous oxide (S/N) or propofol-remifentanil (P/R) anesthesia. Four patients taking angiotensin II receptor antagonists were excluded post hoc. Mean arterial pressure and heart rate, as well as SjvO 2 and SctO 2, were measured before (postinduction baseline in supine position) and after BCP. Results: Mean arterial pressure decreased by BCP in both groups. It was, however, significantly higher in S/N (n = 19) than in P/R group (n = 17) at 7 to 8 min after the positioning. SjvO 2 also significantly decreased after BCP in both groups, the magnitude of which was lower in S/N than in P/R group (11 ± 10% vs. 23 ± 9%, P = 0.0006). The incidences of SjvO 2 <50% and mean arterial pressure less than 50 mmHg were lower in S/N group, but SctO 2and the incidence of cerebral desaturation (more than 20% decrease from baseline) did not significantly differ between the groups. SctO 2 and SjvO 2 were only weakly correlated (β = 0.218, r 2 = 0.133). Bland-Altman analysis showed a mean difference of-7.2% with 95% limit of agreement between-38.2% and 23.8%. Conclusions: The margin of safety against impaired cerebral oxygenation is greater and SjvO 2 is more preserved with S/N than with P/R anesthesia. SctO 2 may not be reliable in detecting a low SjvO 2 during the surgery in BCP. © 2012, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.