Electroencephalographic characteristics of emergence from propofol/sufentanil total intravenous anesthesia

We recorded the electroencephalogram (EEG) in 16 patients during propofol/sufentanil total intravenous anesthesia to determine whether EEG changes might predict imminent awakening during emergence. Changes in absolute and relative power in four frequency bands, median frequency (MF), 95th percentile frequency (F95), and two frequency band power ratios (beta/alpha and (alpha+beta)/delta) were quantified. One minute before eye opening, absolute power in the delta and alpha bands had decreased to 49% (25%-73%) and 42% (25%-58%) of the value during the infusion (P > 0.005). MF, F95, and the two frequency band power ratios increased during emergence (P > 0.05). Of the individual spectral variables, only a 50% decrease in absolute alpha power was more than 90% sensitive and specific in predicting eye opening. We conclude that, although pronounced EEG changes occur during emergence from propofol/sufentanil anesthesia, the EEG does not reliably predict eye opening.