Relationship between Bispectral Index Values and Volatile Anesthetic Concentrations during the Maintenance Phase of Anesthesia in the B-Unaware Trial

作者：Elizabeth L. Whitlock, Alexander Villafranca, Nan Lin, Ben Julian A. Palanca, Eric Jacobsohn, Kevin J. Finkel, Lini Zhang, Beth Burnside, Heiko A. Kaiser, Alex S. Evers, Michael Simon Avidan · 发表于：Anesthesiology · 年份：2011 · DOI：10.1097/aln.0b013e3182395dcb · 被引用次数：146 · 研究领域：Anesthesia and Sedative Agents、Nausea and vomiting management、Intensive Care Unit Cognitive Disorders

BACKGROUND: Hypnotic depth during anesthesia affects electroencephalography waveforms and electroencephalogram-derived indices, such as the bispectral index (BIS). Titrating anesthetic administration against the BIS assumes reliable relationships between BIS values, electroencephalogram waveforms, and effect site concentration, beyond loss of responsiveness. Associations among BIS, end-tidal anesthetic concentrations (ETAC), and patient characteristics were examined during anesthetic maintenance, using B-Unaware trial data. METHODS: Pharmacokinetically stable ETAC epochs during intraoperative anesthetic maintenance were analyzed. A generalized estimating equation determined independent relationships among BIS, ETAC (in age-adjusted minimum alveolar concentration equivalents), patient characteristics, and 1-yr mortality. Further individual and population characteristics were explored graphically. RESULTS: A total of 3,347,523 data points from 1,100 patients were analyzed over an ETAC range from 0.42 to 1.51 age-adjusted minimum alveolar concentration. A generalized estimating equation yielded a best predictive equation: BIS = 62.9-1.6 (if age younger than 60 yr) -1.6 (if female) -2.5 (if American Society of Anesthesiologists physical status more than 3) -2.6 (if deceased at 1 yr) -2.5 (if N2O was not used) -1.4 (if midazolam dose more than 2 mg) -1.3 (if opioid dose more than 50 morphine equivalents) -15.4 × age-adjusted minimum alveolar concentration. Although a population re...