Caudal anesthesia reduces the minimum alveolar concentration of enflurane for laryngeal mask airway removal in children<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 邓晓明 肖文静 唐耿志 罗茂平 胥琨琳 薛富善 安刚 中国医学科学院 中国协和医科大学 整形外科医院麻醉科 (100041) Deng Xiaoming,Xiao Wenjing,Tang Genzhi et al. Department of Anesthesiology,Plastic Surgery Hospital,Chinese Academy of Medical Sciences,Peking Union Medical College,Beijing,100041,PR of China. ABSTRACT Objective To investigate the effects of the caudal analgesia on the minimal alveolar concentration of enflurane for laryngeal mask airway (LMA) smooth extubation (MACex). Methods We studied 50 nonpremedicated children,aged 3~10 yr,ASA physical status,undergoing hypospadias repair operation. After sevoflurane inhaled induction,children were randomized in a double~blinded fashion to receive LMA insertion with or without ropivacaine caudal analgesia. 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. Results It was found the MACex of enflurane in LMA without caudal anesthesia group was 1.04% (95% Confidence Interval,1.00 - 1.10) and the MACex of enflurane in LMA with caudal anesthesia group was 0.74% (95% Confidence Interval,0.63 - 0.81). Caudal analgesia significantly reduced enflurane requirements by 29% (95% Confidence Interval,22 - 36). Conclusion In conclusion,caudal analgesia significantly reduced the MACex of enflurane by approximately 29%. The possible mechanism may be the preemptive analgesia of caudal blockade and the general anesthetics effects of caudal blockade. Keywords Caudal Analgesia. Laryngeal Mask Airway. Minimum alveolar concentration. Extubation. 骶管阻滞是小儿区域麻醉中最常用的神经阻滞技术,其操作相对简单,阻滞效果可靠,主要用于脐以下的手术。喉罩通气道目前广泛应用于小儿麻醉时的呼吸道维持,具有创伤小,麻醉效果可靠,手术后并发症少等优点。在小儿喉罩通气道拔除时,深麻醉拔管较浅麻醉拔管的并发症明显减少[1,2]。临床观察已经证实,神经阻滞可以明显提高咪达唑仑的镇静作用,提示中枢神经阻滞本身可能具有镇静的效果[3]。本研究假定骶管阻滞可以降低小儿喉罩通气道拔管时的麻醉深度,用小儿喉罩通气道拔除时安氟烷的肺泡最低有效浓度为指标(MACLMA)[6],观察小儿罗哌卡因骶管阻滞对喉罩通气道拔除时安氟烷的肺泡最低有效浓度的影响。 |