Sevoflurane EC50 Values for the Removal of the Laryngeal Mask Airway in Children with Teracainum Gel

Objective:To determine the concentration of sevoflurane where 50%(EC50 ) of the attempts to remove the laryngeal mask airway(LMA ) with the Teracainum Gel would be successful in children.Methods:Twenty-five nonpremedicated children,aged 3-8 years old.ASA physical status I,scheduled for extremities or peripherical surgery were enrolled in this study.General anesthesia was induced with sevoflurane and maintained with sevoflurane and nitrous oxide in oxygen.After the surgery,the target concentration was maintained for at least 10 min,and then the LMA was removed.Each target concentration was predetermined by the Dixon's up-and-down method(with 0.1 Vol% as a step size),starting at 1.20 Vol%concentration of sevoflurane.A removal accomplished without coughing,teeth clenching,gross purposeful movement,breath holding or laryngospasm,during or within 1 min after removal was considered to be successful.Results:The concentration of sevoflurane to achieve successful LMA removal in 50%of children was 1.22 Vol%(95%CL,0.99 Vol%-1.49 Vol%).Conclusion;The EC50 value of sevoflurane for LMA smooth extubation in children aged 3-8 years old with teracainum gel was 1.22 Vol%.