Amnesia for electric dental pulp stimulation and picture recall test under different levels of propofol or midazolam sedation.

AIM To compare the amnesic effect of propofol and midazolam to electric dental pulp stimulation (invasive) and picture recall test (non-invasive) at two sedation levels with the aid of bispectral index (BIS) monitoring. METHODS The subjects were 10 male volunteers (24-34 years) classified as ASA physical status I. Propofol was administered to achieve a sedation score of three with a target-controlled infusion technique; it was then regulated to give a sedation score of two (P group). Midazolam was administered by a titration dosage to achieve a sedation score of three (M group). It then gradually decreased to give a sedation score of two. The BIS score, sedation score, plasma/serum concentration of propofol and midazolam, blood pressure, pulse rate, respiratory rate, end-tidal CO(2) tension and arterial oxygen saturation were observed at each sedation level in both groups. Amnesic effects were evaluated using a picture recall test and electric dental pulp stimulation. RESULT No difference was observed in the amnesic effect evaluated by picture recall test at the two sedation levels. Likewise, there was no difference at a sedation score of three when the amnesic effect was evaluated by electric dental pulp stimulation. In contrast, a significant difference was observed at a sedation score of two; midazolam produced amnesia in more subjects than did propofol. CONCLUSION Propofol and midazolam did not show any significant difference in amnesic effects to non-invasive stimuli. For invasive stimuli, midazolam showed a stronger amnesic effect at the moderate sedation level, but not at the deeper sedation level.