TECHNOLOGY,COMPUTING, AND SIMULATION SOCIETY FOR TECHNOLOGY IN ANESTHESIA SECTION EDITOR STEVEN J. BARKER The Effect of Cerebral Monitoring on Recovery After General Anesthesia: A Comparison of the Auditory Evoked Potential and Bispectral Index Devices with Standard Clinical Practice Alejandro Recart, MD, Irina Gasanova, PhD, MD, Paul F. White, PhD, MD, Tojo Thomas, MS, Babatunde Ogunnaike, MD, Mohammed Hamza, MD, and Agnes Wang, MS From the Department of Anesthesiology and Pain Management University of Texas Southwestern Medical Center at Dallas The use of cerebral monitoring may improve the ability of anesthesiologists to titrate anesthetic drugs. However, there is controversy regarding the impact of the alleged anesthetic-sparing effects of cerebral monitoring on the recovery process and patient outcome. We designed this prospective double-blinded, sham-controlled study to evaluate the impact of intraoperative monitoring with the electroencephalogram bispectral index (BIS™) or audi- tory evoked potential (AEP) device on the usage of desflu- rane and the time to discharge from the recovery room, as well as on patient satisfaction with their anesthetic experi- ence and recovery. Ninety healthy patients undergoing laparoscopic general surgery procedures using a stan- dardized anesthetic technique were randomly assigned to one of three monitoring groups: standard clinical practice (control), BIS-guided, or AEP-guided. Both the BIS and AEP monitors were connected to all patients before induc- tion of general anesthesia. In the control group, the anes- thesiologists were not permitted to observe the BIS or AEP index values during the intraoperative period. In the BIS- guided group, the volatile anesthetic was titrated to main- tain a BIS value in the range of 45–55. In the AEP-guided group, the targeted AEP index range was 15–20. The BIS and AEP indices, as well as end-tidal desflurane concen- tration, were recorded at 3–5 min intervals. Recovery times to awakening, tracheal extubation, fast-track score 12, and postanesthesia care unit (PACU) discharge criteria were recorded at 1–10 min intervals. In addition, patient satisfaction with anesthesia and quality of recov- ery were evaluated on 100- and 18-point scales, respec- tively, at 24 h after surgery. The AEP- and BIS-guided groups were administered significantly smaller average end-tidal desflurane concentrations than the control group (3.8  0.9 and 3.9  0.6 versus 4.7  1.7, respec- tively) (P  0.01). Although the emergence times to eye opening, tracheal extubation, and obeying commands were consistently shorter in the AEP and BIS groups (6  4 and 6  5 versus 8  8 min; 6  5 and 6  4 versus 11  10 min; and 8  4 and 7  4 versus 12  9 min, respective- ly), only the extubation times were significantly different from the control group (P  0.05). More importantly, the length of the PACU stay was significantly shorter in both the AEP- and BIS-guided groups (79  43 and 80  47 versus 108  58 min, respectively) (P  0.05). The patients’ quality of recovery was also significantly higher in the two monitored groups (15  2 versus 13  3 in the control group, P  0.05). We concluded that cerebral monitoring with either the BIS or AEP devices reduced the mainte- nance anesthetic (desflurane) requirement, resulting in a shorter length of stay in the PACU and improved quality of recovery after laparoscopic surgery. However, there were no significant outcome differences between the two cerebral monitored groups. (Anesth Analg 2003;97:1667–74) T he impact of monitoring the level of conscious- ness during general anesthesia on recovery re- mains controversial (1–5). The monitoring of pa- tients’ vital signs remains the most common method for determining “depth of anesthesia” during surgery. The value of cerebral monitoring as an adjuvant to clinical monitoring of autonomic responses during surgery has been questioned (1,3,5). However, recent studies have suggested that use of cerebral monitoring could improve early recovery after general anesthesia because of the ability to minimize both over- and underdosage with anesthetic drugs during the main- tenance period (6 – 8). Several different electroencephalographic (EEG)- based algorithms have been evaluated in an attempt to correlate EEG-derived indices and anesthetic drug con- centrations with clinical signs of depth of anesthesia Supported, in part, by an educational grant from Alaris Medical Systems (San Diego, CA), and salary support for Dr. P. F. White from the Margaret Milam McDermott Distinguished Chair of Anesthesiology. Accepted for publication July 3, 2003. Address correspondence to Dr. Paul F. White, Department of Anesthesiology and Pain Management, University of Texas South- western Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390 –9068. Address email to paul.white@utsouthwestern.edu. DOI: 10.1213/01.ANE.0000087041.63034.8C ©2003 by the International Anesthesia Research Society 0003-2999/03 Anesth Analg 2003;97:1667–74 1667