Postoperative recovery with bispectral index versus anesthetic concentration-guided protocols

Use of the bispectral index (BIS) monitor has been suggested to decrease excessive anesthetic drug administration, leading to improved recovery from general anesthesia. The purpose of this substudy of the B-Unaware and BAG-RECALL trials was to assess whether a BIS-based anesthetic protocol was superior to an end-tidal anesthetic concentration-based protocol in decreasing recovery time and postoperative complications.

Patients at high risk for awareness were randomized to either BIS-guided or end-tidal anesthetic concentration-guided general anesthesia in the original trials. Outcomes included time to postanesthesia care unit discharge readiness, time to achieve a postoperative Aldrete score of 9-10, intensive care unit length of stay, postoperative nausea and vomiting, and severe postoperative pain. Univariate Cox regression and chi-square tests were used for statistical analyses.

The BIS cohort was not superior in time to postanesthesia care unit discharge readiness (hazard ratio, 1.0; 95% CI, 1.0-1.1; n = 2,949), time to achieve an Aldrete score of 9-10 (hazard ratio, 1.2; 95% CI, 1.0-1.4; n = 706), intensive care unit length of stay (hazard ratio, 1.0; 95% CI, 0.9-1.1; n = 2,074), incidence of postoperative nausea and vomiting (absolute risk reduction, -0.5%; 95% CI, -5.8 to 4.8%; n = 789), or incidence of severe postoperative pain (absolute risk reduction, 4.4%; 95% CI, -2.3 to 11.1%; n = 759).

In patients at high risk for awareness, the BIS-guided protocol is not superior to an anesthetic concentration-guided protocol in time needed for postoperative recovery or in the incidences of common postoperative complications.