Similar excitation after sevoflurane anaesthesia in young children given rectal morphine or midazolam as premedication

Abstract

Sevoflurane is a rapid-acting volatile anaesthetic agent frequently used in paediatric anaesthesia despite transient postoperative symptoms of cerebral excitation, particularly in preschool children. This randomised and investigator-blinded study was designed to evaluate whether premedication with an opioid might reduce non-divertible postoperative excitation more than premedication with a benzodiazepine in preschool children anaesthetized with sevoflurane. Ninety-two healthy two to six year-old children scheduled for nasal adenoidectomy were randomised to be given rectal atropine 0.02 mg kg(-1) together with either morphine 0.15 mg kg(-1) or midazolam 0.30 mg kg(-1) approximately 30 min before induction and maintenance of sevoflurane anaesthesia. The patient groups were compared pre- and postoperatively by repeated clinical assessments of cerebral excitation according to a modified Objective Pain Discomfort Scale, OPDS. There were no statistically significant postoperative differences in incidence, extent or duration of excitation between children given morphine or midazolam for premedication, whereas morphine was associated with more preoperative excitation than was midazolam. The study groups did not differ significantly with respect to age, weight, duration of surgery and anaesthesia, and time from tracheal extubation to arrival in and discharge from the postoperative ward. In this study morphine for premedication in young children anaesthetized with sevoflurane was associated with similar postoperative and higher preoperative OPDS scores compared with midazolam. These findings indicate that substitution of morphine for midazolam is no useful way of reducing clinical excitation after sevoflurane anaesthesia.