Yaguchi Yuichi, Inomata Shinichi, Kihara Shin-ichi, Baba Yasuyuki, Kohda Yukinao, Toyooka Hidenori
Department of Anesthesiology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba City, Ibaraki, Japan.
Anesth Analg. 2002 Apr;94(4):863-6, table of contents. doi: 10.1097/00000539-200204000-00016.
The effects of clonidine on minimum alveolar concentration for tracheal extubation (MAC-ex) have not been elucidated. Clonidine may lead to prolonged emergence from anesthesia. We investigated the effects of oral clonidine premedication on MAC-ex and examined the emergence properties of sevoflurane in children. Sixty ASA physical status I pediatric patients, aged from 2 to 9 yr, were randomly divided into one of three groups and received placebo, clonidine 2 microg/kg, or clonidine 4 microg/kg (n = 20 each) orally, 100 min before the induction of anesthesia. The induction of anesthesia, tracheal intubation, and maintenance of anesthesia were performed with sevoflurane in air and oxygen. MAC-ex was defined according to the modification of Dixon's up-and-down method, with 0.25% as a step size. In addition, in the Control and 4 microg/kg groups, the time from tracheal extubation to spontaneous eye opening (eye-opening time) and the time from tracheal extubation to leaving the operating room (awakening time) were recorded. MAC-ex for sevoflurane (mean +/- SD) was 1.63% +/- 0.13%, 1.04% +/- 0.26%, and 0.66% +/- 0.09% respectively in the Control group, 2 microg/kg group, and 4 microg/kg group. Significant differences were observed among the three groups. The eye-opening times were 5.7 +/- 3.5 min in the Control group and 5.1 +/- 1.0 min in the 4 microg/kg group. The awakening times were 9.7 +/- 3.7 min in the Control group and 9.2 +/- 3.8 min in the 4 microg/kg group. No significant differences were observed among the groups.
Oral clonidine premedication decreased MAC for tracheal extubation for sevoflurane dose dependency and did not prolong emergence from anesthesia.
可乐定对气管拔管时最低肺泡浓度（MAC-ex）的影响尚未阐明。可乐定可能导致麻醉苏醒延迟。我们研究了口服可乐定进行术前用药对MAC-ex的影响，并观察了七氟醚在儿童中的苏醒特性。60例年龄在2至9岁的美国麻醉医师协会（ASA）I级儿科患者，随机分为三组，在麻醉诱导前100分钟分别口服安慰剂、2μg/kg可乐定或4μg/kg可乐定（每组20例）。采用七氟醚与空气和氧气混合进行麻醉诱导、气管插管和维持麻醉。MAC-ex根据Dixon上下法的改良方法定义，步长为0.25%。此外，在对照组和4μg/kg组中，记录从气管拔管到自主睁眼的时间（睁眼时间）以及从气管拔管到离开手术室的时间（苏醒时间）。对照组、2μg/kg组和4μg/kg组七氟醚的MAC-ex（均值±标准差）分别为1.63%±0.13%、1.04%±0.26%和0.66%±0.09%。三组间差异有统计学意义。对照组的睁眼时间为5.7±3.5分钟，4μg/kg组为5.1±1.0分钟。对照组的苏醒时间为9.7±3.7分钟，4μg/kg组为9.2±3.8分钟。组间差异无统计学意义。
口服可乐定进行术前用药可使七氟醚气管拔管时的MAC呈剂量依赖性降低，且不会延长麻醉苏醒时间。
