Greater Incidence of Delirium during Recovery from Sevoflurane Anesthesia in Preschool Boys

Background In the authors' clinical experience, preschool children are more likely to show delirium after sevoflurane than are older children. Methods Sixty-three preschool boys aged 3-5 yr (classified as American Society of Anesthesiologists [ASA] physical status I), and 53 school-age boys aged 6-10 yr (ASA physical status I) who underwent minor urologic surgery were randomly assigned to receive either halothane or sevoflurane, thus creating four groups: preschool-halothane (n = 32), preschool-sevoflurane (n = 31), school-halothane (n = 27), and school-sevoflurane (n = 26). Anesthesia was induced by inhalation of halothane or sevoflurane in oxygen and was maintained at 1 minimum alveolar concentration of each agent throughout surgery. For intra- and postoperative analgesia, caudal block with 0.5-1.0 ml/kg 0.25% plain bupivacaine and topical infiltration with 3-5 ml 1% lidocaine were provided for all patients. Recovery characteristics and incidence of delirium on emergence were compared among the four groups. Results Two patients in the preschool-halothane group, one in the preschool-sevoflurane group, and one in the school-halothane group were excluded from the comparison because of insufficient analgesia or agitation before induction. In both age groups, the time to emergence from sevoflurane was significantly faster (about 3 min) than from halothane. The incidence of delirium during recovery in the preschool-sevoflurane group (40%) was significantly greater than that in the other groups (preschool-halothane, 10%; school-halothane, 15.4%; school-sevoflurane, 11.5%). Conclusion Sevoflurane provided quicker emergence and early recovery compared with halothane, but the incidence of delirium was greater in preschool boys after sevoflurane.