Purpose: To study the effect of midazolam premedication on the recovery characteristics of sevoflurane anesthesia induced with propofol in pediatric outpatients.

Methods: Sixty children, one to three years, presenting for ambulatory adenoidectomy were randomly assigned , in a double-blind fashion, to receive either 0.5 mg x kg(-1) midazolam (Group M) or placebo (Group P) p.o. 30 min before anesthesia. Anesthesia was induced with 10 microg x kg(-1) atropine, 10 microg x kg(-1) alfentanil, and 3-4 mg x kg(-1) propofol i.v.. Tracheal intubation was facilitated with 0.2 mg x kg(-1) mivacurium. Anesthesia was maintained with nitrous oxide/oxygen (FiO2 0.3) and sevoflurane with controlled ventilation. Recovery characteristics were compared using the modified Aldrete scoring system, the Pain/Discomfort scale and measuring specific recovery end-points (emergence, full Aldrete score, discharge). A postoperative questionnaire was used to evaluate the children's well-being at home until 24 hr after discharge.

Results: Emergence from anesthesia (22 +/- 9 vs 16 +/- 6 min (mean +/- SD), P = 0.005) and achieving full Aldrete scores (30 +/- 11 vs 24 +/- 16 min, P = 0.006) were delayed in patients receiving midazolam. Children in the placebo group were given postoperative analgesia sooner than those in the midazolam group (18 +/- 11 vs 23 +/- 8 min, P = 0.009). More children premedicated with midazolam suffered from arousal distress (20% vs 3%, P = 0.04) and scored higher on the Pain/Discomfort scale (P = 0.004) at 20 min after arrival in the recovery room. Discharge was not affected by premedication and well-being at home was similar in the groups.

Conclusions: Oral premedication with midazolam delays early recovery but not discharge after ambulatory sevoflurane anesthesia induced with propofol in children one to three years. Midazolam did not improve the quality of recovery.