Prediction of Movement Using Bispectral Electroencephalographic Analysis During Propofol/Alfentanil or Isoflurane/Alfentanil Anesthesia

Abstract
Conventional electroencephalographic (EEG) analysis techniques do not use the phase information from the Fourier analysis.This study used a new technique of EEG analysis, bispectral analysis, which measures interfrequency phase relationships in the EEG. Using a reference database, and a process of multivariate discriminant analysis, we developed a univariate bispectral variable, the bispectral index (BIS). This study was designed to test the efficacy of BIS in predicting movement to incision during either an isoflurane/alfentanil anesthetic or a propofol/alfentanil anesthetic technique. Fifty consenting patients were randomized to two groups; one received isoflurane/alfentanil and the other, propofol/alfentanil for anesthesia. EEG was recorded using a microcomputer system and the data were analyzed off-line. Hemodynamic variables were also recorded. After skin incision, each patient was observed carefully for 2 min to detect purposeful movement. A significant difference was found between the BIS values for movers versus nonmovers within each of the two treatment groups (P (Anesth Analg 1995;80:780-5)