右美托咪啶对平稳拔除气管导管时七氟烷半数有效浓度的影响

Dexmedetomidine reduces median effective concentration(EC_(50)) of sevoflurane during endotracheal extubation

目的观察术中应用右美托咪啶对全麻患者术后平稳拔除气管导管时七氟烷半数有效浓度（EC50），以及患者苏醒质量的影响，探讨右美托咪啶改善全麻苏醒质量的可行性。方法将60例患者按随机数字表法分为对照组和右美托咪啶组，各30例。右美托眯啶组10min内静脉泵注右美托咪啶1μg／kg后改为0．5μg／（kg·h）。对照组泵注同等量的0.9％氯化钠溶液。常规给予麻醉诱导及维持，手术结束时根据Dixon序贯法确定拔除气管导管的七氟烷浓度，并观察患者气管导管拔管时间、睁眼时间、Ramsay评分达3、1分时间以及并发症情况。结果右美托咪啶组和对照组患者拔除气管导管时七氟烷EC50分别是0.22MAC和O.61MAC，其95％CI分别为（0.14～0.30）和（0．47～0．75）MAC．右美托咪啶组和对照组患者气管导管拔管时间、睁眼时间、Ramsay评分达3、1分时间比较差异均无统计学意义（均P〉0．05）。右美托咪啶组和对照组患者在拔管后出现低氧血症、呼吸抑制、需辅助通气、需放置口咽通气道例数分别为2、1、1、0例和5、4、2、2例，两组比较差异有统计学意义（P〈0．05）。结论围术期应用右美托咪啶可降低平稳拔除气管导管所需七氟烷EC50对患者苏醒时间无明显影响，可降低拔管后七氟烷所致呼吸抑制的发生率，改善苏醒质量。

Objective TO investigate the effect of dexmedetomidine on median effective concentration （EC50） of sevoflurane during endotracheal extubation in patients with general anesthesia. Methods Sixty patients were randomly divided into control group and Dex group. In Dex group 0.5μ g/ （kg·h） dexmedetomidine was given by intravenous injection pump after injection of 1μ g/kg for 10min; patients in control group were given injection of same amount of saline solution. The induction and maintenance of anesthesia was conventionally performed. At the end of the operation the concentration of sevoflurane during endotracheal extubation was determined by Dixon sequential method and time for tube withdrawal, time of eye opening, Ramsay score of 3h, 1rain and complications were documented. Results The EC50 of sevoflurane during tracheal extubation in Dex group and control group were 0.22MAC （95%CI 0.14-0.30） and 0.61MAC （95%CI 0.47-0.75）, respectively （P〈0.05）. There were no significant differences in time of trachea extubation, time of eye-opening and the time of Ramsay score up to 1 and 3 points of the patients awakening from the general anesthesia between two groups. The case numbers of hypoxemia, respiratory inhibition, assisted ventilation and cuffed oropharyngeal airway were 2, 1, 1, 0 in Dex group and 5, 4, 2, 2 in control group, respectively （P〈0.05）. Conclusion Perioperative application of dexmedetomidinein can reduce EC50 of sevoflurane during endotracheal extubation, it can also reduce the incidence of respiratory depression and improve the quality of awakening for patients under general anesthesia.