Xiao W, Deng X
Department of Anesthesiology, Plastic Surgery Hospital, The Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
Anesth Analg. 2001 Jan;92(1):72-5. doi: 10.1097/00000539-200101000-00014.
The end-tidal anesthetic gas concentration required to prevent the anesthetized patient from coughing or moving during or immediately after the laryngeal mask airway (LMA) extubation is not known. We sought to determine the minimum alveolar concentration of enflurane required for the removal of the LMA in children. We studied 21 nonpremedicated children between 4 and 11 yr of age, ASA physical status I, undergoing procedures below the umbilicus. General anesthesia was induced with a mask by using sevoflurane, nitrous oxide, and oxygen, and the LMA was inserted. Anesthesia was maintained with enflurane, nitrous oxide, and oxygen. At the end of surgery, a predetermined end-tidal enflurane concentration was achieved, and the LMA was removed. Each concentration at which the LMA extubation was attempted was predetermined by the up-and-down method (with 0.1% as a step size). When LMA removal was accomplished without coughing, clenching teeth, or gross purposeful muscular movements during or within 1 min after removal, it was considered a successful LMA removal. Removal was considered to be unsuccessful in patients who developed breath holding or laryngospasm during or immediately after LMA removal. The minimum alveolar concentration of enflurane at which 50% of children had a successful LMA removal was found to be 1.02% (95% CL, 0.95%-1.11%), and the 95% effective dose for successful extubation was 1.14% (95% CL, 1.07%-1.66%). In conclusion, the LMA removal may be accomplished without coughing or moving at 1.02% end-tidal enflurane concentration in 50% of anesthetized children aged 4-11 yr.
There may be fewer problems associated with the laryngeal mask airway extubation when patients are deeply anesthetized. The purpose of this study was to determine the minimum concentration of enflurane for successful removal of the laryngeal mask in children.
在喉罩气道（LMA）拔管期间或拔管后立即防止麻醉患者咳嗽或移动所需的呼气末麻醉气体浓度尚不清楚。我们试图确定儿童拔除LMA所需的恩氟烷最低肺泡浓度。我们研究了21名4至11岁、ASA身体状况为I级、接受脐以下手术的未用术前药的儿童。采用七氟烷、氧化亚氮和氧气面罩诱导全身麻醉，然后插入LMA。用恩氟烷、氧化亚氮和氧气维持麻醉。手术结束时，达到预定的呼气末恩氟烷浓度，然后拔除LMA。尝试拔除LMA的每个浓度均通过上下法预先确定（步长为0.1%）。如果在拔除LMA期间或拔除后1分钟内拔除LMA时未出现咳嗽、咬牙或明显的有意识肌肉运动，则认为LMA拔除成功。如果在LMA拔除期间或拔除后立即出现屏气或喉痉挛，则认为拔除不成功。发现50%的儿童成功拔除LMA时恩氟烷的最低肺泡浓度为1.02%（95%可信区间，0.95%-1.11%），成功拔管的95%有效剂量为1.14%（95%可信区间，1.07%-1.66%）。总之，在4至11岁的麻醉儿童中，50%的患儿在呼气末恩氟烷浓度为1.02%时可在不咳嗽或移动的情况下完成LMA拔除。
当患者深度麻醉时，与喉罩气道拔管相关的问题可能较少。本研究的目的是确定儿童成功拔除喉罩所需的恩氟烷最低浓度。
