摘要:目的:定量測定50 %小兒在喉罩表面涂抹丁卡因膠漿的情況下平穩(wěn)拔除喉罩時呼氣末七氟烷濃度。方法:25例擇期行四肢及體表手術的患兒,高流量吸入七氟烷誘導并以七氟烷和氧化亞氮維持麻醉,不使用肌肉松弛劑及靜脈麻醉藥物,手術結束后停止吸入氧化亞氮,并維持設定的七氟烷濃度10min后拔除喉罩。根據(jù)Dixon序貫法確定喉罩拔除時的七氟烷濃度,每0.1 Vol%七氟烷為1個增減單位。患兒未出現(xiàn)咳嗽、牙關緊閉、體動、屏氣及喉痙攣則認為拔除喉罩平穩(wěn)。結果:50 %小兒平穩(wěn)拔除喉罩時呼氣末七氟烷濃度(EC50)為1.22 Vol%(95 %的置信區(qū)間分別為0.99 Vol%～1.49 Vol%)。結論:在喉罩表面涂抹丁卡因膠漿的情況下,3～8歲患兒喉罩滿意拔除時呼氣末七氟烷EC50值為1.22 Vol%。Abstract: 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: Twentyfive nonpremedicated children, aged 38 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 upanddown 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 38 years old with teracainum gel was 1.22 Vol%.