Background: Sevoflurane is widely used in paediatric anaesthesia but frequently causes emergence agitation (EA). This study evaluated whether limiting the sevoflurane concentration by combining remifentanil with sevoflurane reduced the incidence of EA.

Methods: Eighty-four preschool children scheduled for adenotonsillectomy were randomly assigned to either the remifentanil or sevoflurane group. In the remifentanil group, anaesthesia was induced with thiopental, rocuronium, and 1% sevoflurane. It was maintained with 1% sevoflurane, 60% nitrous oxide in oxygen, and a continuous infusion of remifentanil. For the sevoflurane group, anaesthesia was induced with thiopental, rocuronium, and 8% sevoflurane, and was maintained with 2-3% sevoflurane. Both groups received ketorolac 1 mg/kg and dexamethasone 0.15 mg/kg. EA was measured using the paediatric anaesthesia emergence delirium (PAED) scale and a four-point EA scale in the post-anaesthesia care unit.

Results: The scores on the PAED scales were significantly lower in the remifentanil group than in the sevoflurane group [median (interquartile range); 6 (4.25-10.25) vs. 11 (7.75-14.0), P = 0.007], and the proportion of patients with PAED scores ≥ 10 was significantly lower in the remifentanil group than in the sevoflurane group [15 (35.7%) vs. 27 (64.2%), P = 0.009]. The incidence of EA evaluated using the four-point scale was also lower in the remifentanil group [11 (26.1%) vs. 21 (50%), respectively, P = 0.025].

Conclusion: The incidence of EA was lower in children undergoing adenotonsillectomy who received a lower concentration of sevoflurane combined with remifentanil than in those given a higher concentration of sevoflurane without remifentanil.