Abstract
We investigated the effects of dexmedetomidine infusion on the end-tidal concentration of sevoflurane required for smooth removal of the laryngeal mask airway (LMA) and on the incidence of respiratory complications during postoperative recovery in paediatric patients anaesthetised with sevoflurane. Eighty-seven patients (ASA 1 or 2, aged 3–7 years) were randomly allocated to receive saline (Group C), 0.5 μg/kg dexmedetomidine (Group D1), or 1 μg/kg dexmedetomidine (Group D2) after LMA insertion. A predetermined end-tidal sevoflurane concentration for each patient was determined using the Dixon's up-and-down method (starting at 2.2% and step was 0.2%). The LMA was removed after the predetermined concentration had been maintained stable for five minutes. Sevoflurane minimum alveolar concentration for smooth LMA removal and postoperative recovery were assessed. The end-tidal concentration of sevoflurane required for smooth LMA removal in 50% of children (MACLMA-RM) in Group D2 (0.84±0.15%) was significantly lower than in Group D1 (1.39±0.20%; P=0.003), the latter being significantly lower than in Group C (1.73±0.14%; P <0.001). The incidence of breath-holding was significantly lower in Group D2 (3%) than in Group C (27%;P=0.009), but comparable between Groups D1 (17%) and C (P=0.385). The incidence of severe coughing was significantly lower in Groups D1 (14%) and D2 (6%) as compared to Group C (39%; P=0.005), but comparable between Groups D1 and D2 (P=0.323). In conclusion, dexmedetomidine infusion produced a dose-dependent decrease in the end-tidal concentration of sevoflurane required for smooth LMA removal in children and was associated less agitation in the post-anaesthetic care unit.