RESUMO
Sevoflurane is a volatile anaesthetic agent with low pungency, nonirritating odor, and low blood/gas partition coefficient that makes it an attractive alternative to halothane. However, a high incidence of emergence agitation [EA] has been reported in paediatric patients after sevoflurane anaesthesia. The underlying mechanism of sevoflurane-induced EA remains unclear. Rapid recovery of consciousness [emergence] from sevoflurane anaesthesia has been proposed as one possible mechanism. It was, therefore, hypothesized that sedatives such as midazolam may counteract sevoflurane's rapid emergence and thus reduce the incidence and the severity of sevoflurane-induced EA. This prospective, controlled, single-blinded study included 88 ASA class I or II paediatric patients scheduled for elective outpatient surgery. Patients were assigned to receive either oral midazolam [0.2 mg kg-_ as anaesthetic premedication] or saline [oral normal saline as premedication] before the conduct of anaesthesia. Induction and maintenance of anaesthesia were uniform in both groups. Induction of anaesthesia was made possible with 8% sevoflurane and N2O in 50% O2. Intubation was performed straight without the aid of muscle relaxant and the ventilator was set to maintain normocapnia. Anaesthesia was maintained with 3% sevoflurane and N2O in 50% O2 until the surgery was over. All matters of relevant time periods were recorded [induction, surgical procedure, extu bation and transportation]. In the post-anaesthesia care unit [PACU], adverse events, the incidence and the severity of EA, analgesic requirement, duration of PACU stay, and parental as well as PACU nurses' satisfaction were evaluated. A significant lower incidence and less severity of EA were noted in patients premedicated with midazolam. Less postoperative analgesia was required in patients who had received midazolam. Although midazolam premedicated patients remained sedated after sevoflurane anaesthesia, the duration of the PACU stay was not significantly different from that of saline-treated patients. Both parents and PACU nurses were more satisfied with midazolam as premedication. It was concluded that premedication with oral midazolam is safe, convenient and effective in decreasing the occurrence of sevoflurane-induced Emergence agitation [EA]. It does not delay discharge from PACU and is suitable for outpatient surgery