右美托咪定用于丙泊酚麻醉诱导时适宜负荷剂量的研究

Proper loading dose of dexmedetomidine for propofol induction of general anesthesia in patients

目的：观察右美托咪定不同剂量对全麻患者丙泊酚诱导期间血流动力学的影响,探讨右美托咪定的适宜输注负荷剂量。方法：选择ASAⅠ~Ⅱ级择期手术患者60例,随机分为5组（每组n=12）：生理盐水对照组（C组）,右美托咪定0.25,0.50,0.75,1.00μg·kg-14组（D1-4组）。各组使用Graseby3500泵于麻醉诱导前10 min内泵注完毕,后丙泊酚靶控输注（TCI）泵入,每次增加0.5μg·mL-1,直至患者意识消失。记录入室（T0）、给药后5 min（T1）、10 min（T2）、睫毛反射消失时（T3）、意识消失时（T4）、置喉镜（T5）、气管插管后1 min（T6）、3 min（T7）时的心率（HR）、平均动脉压（MAP）值、脉搏血氧饱和度（SpO2）。记录睫毛反射消失时（T3）、意识消失时（T4）丙泊酚效应室浓度及剂量。结果：与T0比较,D1组HR,MAP在T5,T6时间点显著升高（P〈0.05）;D2组、D3组HR,MAP在T1-T4降低（P〈0.05）;D4组HR在各时间点均降低（P〈0.05）,MAP在T1,T2时间点显著升高（P〈0.05）。D2组、D3组、D4组在T3,T4时丙泊酚效应室浓度及用量比C组、D1组明显降低（P〈0.05）。麻醉诱导期间D4组出现呼吸抑制和心动过缓的发生率明显多于其他各组。结论：右美托咪定负荷剂量0.50-0.75μg·kg^-1复合丙泊酚全麻诱导期间血流动力学平稳,能明显降低丙泊酚效应室浓度和用量,并呈线性相关性,大剂量（0.75μg·kg^-1）具有封顶效应。

Objective：To observe the effects of different doses of dexmedetomidine on hemodynamics during induction of general anesthesia with propofol,and to investigate the proper loading dose of dexmedetomidine.Methods：Patients（n = 60） with ASA I - II level undergoing elective surgery were randomly divided into five groups.Graseby3500 pump was used to infuse dexmedetomidine（0,0.25,0.50,0.75 and 1.00 μg·kg^- 1） within 10 min before induction of anesthesia.All the patients received TCI of propofol with an increment of 0.5 μg·mL- 1 each time,until they were unconscious.In each group,MAP,HR and SpO2 were monitored at pre-induction（T0）;5 min（T1）,10 min（T2） after the treatment;eyelash reflex disappearance（T3）;loss of consciousness（T4）;laryngoscope（T5）;1 min（T6） and 3 min（T7） after intubation.The concentrations of propofol in an effect chamber（PCe） and its doses（P） were recorded when eyelash reflex disappearance（T3） and loss of consciousness（T4）.Results：Compared with T0,HR and MAP were decreased significantly at T5 to T6（P〈0.05） in 0.25 μg·kg^- 1 group;HR and MAP at T1- T4 were decreased in 0.50 and 0.75 μg·kg^- 1 groups（P〈0.05）;HR were decreased at various time points in 1.00 μg·kg^- 1 group（P〈0.05）.The MAP at T1 to T2 was significantly increased（P〈0.05）.Concentrations of propofol in PCe and its doses（P） at T3 to T4 were significantly lower in 0.50,0.75 and 1.00 μg·kg- 1 groups than in control and 0.25 μg·kg^- 1 groups（P〈0.05）.In 1.00 μg·kg^- 1 group,the incidences of respiratory depression and bradycardia were significantly more than those in other groups.Conclusion：The doses of dexmedetomidine ranging from 0.50 to 0.75 μg·kg- 1 for induction of anesthesia with propofol can effectively stablize the hemodynamics,and significantly reduce the PCe concentration and dose of propofol in a dosedependent manner with a maximum dose of 0.75 μg·kg^- 1.