THE P300 EVENT-RELATED POTENTIAL DURING PROPOFOL SEDATION - A POSSIBLE MARKER FOR AMNESIA

We have studied the effects of conscious sedation with propofol on lon g latency components of the auditory event-related potential (ERP) in 10 normal volunteers (aged 21-41 yr) receiving propofol 75 mu g kg(-1) min(-1) i.v. We examined the effects of propofol on ERP amplitudes an d latencies, and their relationship to delayed recognition performance using a verbal memory test, a selective attention task (button pushin g) and serum concentrations of propofol. During infusion of propofol, subjects were mildly sedated, oriented and readily responsive to verba l commands. ERP were recorded from monopolar F-Z, C-Z and P-Z electrod es. We used a standard paradigm requiring selective attention to rando mly occurring stimuli associated with a task (button push). The peak-t o-peak amplitudes and latencies of the N2 and P3 waves were obtained b efore and during infusion, and 15, 100 and 170 min after infusion. Pro pofol produced a 70% decrease in the amplitude of P3 (P < 0.0001) from baseline and a 50% increase in reaction time. The differential respon se to target compared with nontarget stimuli was maintained during inf usion for both N2 and P3. Memory performance correlated more strongly with changes in P3 amplitude (r = 0.59) than with serum propofol conce ntrations (r = -0.07), although this correlation with memory did not r each statistical significance (P = 0.08). We conclude that P3 amplitud e was profoundly affected by propofol given in sedative concentrations .