SEDATIVE DOSES OF PROPOFOL INCREASE BETA ACTIVITY OF THE PROCESSED ELECTROENCEPHALOGRAM

The effects of sedative infusions of propofol on the processed electro encephalograms (EEG) of eight healthy male volunteers were studied. EE G data for aperiodic analysis were collected during three 5-min period s: before propofol, during propofol infusion, and 30 min after termina tion of the infusion. After an initial dose of 1 mg/kg, subjects recei ved a propofol infusion titrated to produce a standard level of consci ous sedation. The infusion rate was 84 +/- 27 mug.kg-1.min-1 (mean +/- SE) and plasma propofol levels were 2180 +/- 43 ng/mL. Total EEG powe r, defined as the sum of the squares of peak-to-peak amplitudes during each 5-s epoch, increased from 1350 +/- 295 muV2.epoch-1 to 9675 +/-2 390 muV2.epoch-1 during the propofol infusion (P < 0.05); it returned to 1445 +/- 145 muV2.epoch-1 30 min after the infusion was discontinue d (P < 0.05 vs the result during propofol). The change in total power was accompanied by a change in the distribution of power within the EE G spectrum, as the fraction of activity in the beta-band (12-35 Hz) in creased during the infusion from 23% +/- 3% to 44% +/- 5% (P < 0.05). Thirty minutes after the infusion was terminated, the distribution of activity within the EEG spectrum had reverted to prepropofol patterns. The similarity of EEG effects seen with sedative doses of propofol an d benzodiazepines suggests that these drugs may share some neurochemic al effects.