Midazolam enhances anterograde but not retrograde amnesia in pediatric patients.

BACKGROUND

Midazolam sedation has been shown to diminish recall of one to four cards shown prior to induction of general anesthesia in pediatric patients. This promising but limited finding prompted us to investigate the effect of midazolam sedation on retrograde and anterograde recall and recognition in children scheduled for elective surgery.

METHODS

Forty patients aged 4-10 yr were randomized using a double-blind study design to receive either 0.2 mg/kg intranasal midazolam or 0.2 ml/5 kg placebo (distilled water) using a Devilbiss #286 atomizer. To assess postoperative memory of preoperative events, recall and recognition tasks were performed using a series of picture cards designed for this purpose. Retrograde amnesia was measured by postoperative recall and recognition of cards shown prior to midazolam/placebo administration, and anterograde amnesia was measured by postoperative recall and recognition of cards shown during the interval between midazolam/placebo administration and induction of general anesthesia.

RESULTS

Compared to placebo, the midazolam group experienced a significant postoperative reduction in ability to both recall (P < .003) and recognize (P < .001) cards shown subsequent to midazolam/placebo administration (anterograde amnesia). In distinction, there was no difference between groups in postoperative ability to recall or recognize cards shown prior to midazolam/placebo administration (retrograde amnesia).

CONCLUSIONS

These results support and extend the inference that midazolam diminishes anterograde recall. In addition, our findings indicate that midazolam diminishes anterograde recognition, thereby providing partial anterograde amnesia without affecting retrograde memory in pediatric patients.