BISPECTRAL INDEX MONITORING ALLOWS FASTER EMERGENCE AND IMPROVED RECOVERY FROM PROPOFOL, ALFENTANIL, AND NITROUS-OXIDE ANESTHESIA

Background: The bispectral index (BIS), a parameter derived from the e lectroencephalograph (EEG), has been shown to correlate with increasin g sedation and loss of consciousness. This study determined whether ad dition of BLS monitoring to standard anesthetic practice results in im provements in the conduct of anesthesia or in patient outcomes. Method s: Three hundred two patients receiving a propofolalfentanil-nitrous o xide anesthetic were studied at four institutions. Thirty-four patient s were initially enrolled to determine preexisting anesthetic practice and patient outcomes at each institution. Subsequent patients were ra ndomized to either standard clinical practice (SP group), or standard practice plus BIS monitoring (BIS group). In all patients, the anesthe siologist attempted to provide a stable anesthetic with the fastest po ssible recovery. BIS was recorded for all patients, but viewed only in the BIS group. In the BIS group, propofol infusions were adjusted to achieve a target BIS between 45-60, increasing to 60-75 during the fin al 15 min of the case. In the SP group, propofol dose adjustments were made based only on standard clinical signs. Drug use, intraoperative responses, and patient recovery parameters were recorded. Results: Dem ographics were similar between groups. Com pared with the SP group, pa tients in the BIS group required lower normalized propofol infusion ra tes (134 vs. 116 mu g.kg(-1).min(-1); P < 0.001), were extubated soone r (11.22 vs. 7.25 min; P < 0.003), had a higher percentage of patients oriented on arrival to PACU (43% vs. 23%; P < 0.02), had better posta nesthesia care unit (PACU) nursing assessments (P < 0.001), and became eligible for discharge sooner (37.77 us. 31.70 min; P < 0.04). There was no significant difference in the incidence of intraoperative respo nses between the groups. Conclusions: Titrating propofol with BIS moni toring during balanced anesthesia decreased propofol use and significa ntly improved recovery. Intraoperative course was not changed. These f indings indicate that the use of BIS may be valuable in guiding the ad ministration of propofol intraoperatively.