Combining median electroencephalography frequency and sympathetic activity in an index to evaluate opioid...

During rapid opioid detoxification, increased sympathetic activity and a greater median frequency (MF) of activity on electroencephalography (EEG) have been reported. The purpose of this study was to evaluate a new index for detoxification that combines sympathetic activity and MF data. After informed consent was obtained, eight patients were sedated with propofol. The MF of EEG activity derived from frontal electrodes was determined. Heart rate variability was evaluated in 256-second segments by power spectral analysis, and sympathetic activity was determined by the low frequency component. The Hoffman Index for narcotic detoxification was weighted 70% to sympathetic activity and 30% to MF to normalize the difference in scales and to provide adequate weight to the sympathetic component. Opioid detoxification was produced by infusion of 25 mg naloxone for 30 minutes, followed by a 24-hour infusion of 1 mg per hour. The MF showed a rapid increase during high-dose infusion of naloxone, but the peak response occurred 1 to 2 hours later. Sympathetic activation and the Hoffman Index increased more slowly after the start of naloxone infusion, but peak increases in all components occurred at approximately the same time. The peak increases in Hoffman Index (110% of baseline), MF (260%), and sympathetic activity (304%) during administration of naloxone were significant and correlated with respect to time (r = 0.89-0.94). The Hoffman Index showed an early increase related to MF and a well-defined peak response indicative of sympathetic and MF activity. The behavior of the Hoffman Index in relation to the MF and sympathetic activity more clearly indicated the onset of opioid detoxification and the maximum response to opioid reversal than did MF or sympathetic activity alone.