右美托咪定对丙泊酚靶控输注意识消失Cp50的影响

Effects of dexmedetomidine on propofol Cp50 under general anesthesia with propofol TCI

目的观察右美托咪定对丙泊酚靶控输注意识消失Cp50的影响。方法选择年龄18~65岁、ASA分级为Ⅰ~Ⅱ级、体质量指数（BMI）为18~30 kg/m2的择期全身麻醉患者,随机分为4组：空白组（C组）、瑞芬太尼组（Remif组）、右美托咪定（0.5μg/kg）组（Dex1组）、右美托咪定（1.0μg/kg）组（Dex2组）。4组患者均采用丙泊酚行麻醉诱导,待丙泊酚血药浓度与效应室浓度达到平衡时,应用镇静/警觉（OAA/S）评分判断患者的意识情况。根据改良的上下交叉点法增加或减少下一个患者0.5μg/ml丙泊酚血浆靶浓度,直至观察到6个连续上升波形出现,记录每次丙泊酚的靶控浓度值,以计算丙泊酚的Cp50值。结果 4组患者丙泊酚Cp50值分别为C组（3.50±0.27）μg/ml、Remif组（2.33±0.20）μg/ml、Dex1组（3.08±0.26）μg/ml、Dex2组（2.42±0.26）μg/ml。与C组比较,其他3组丙泊酚Cp50值均明显降低（P〈0.05）;Dex1组和Remif组比较,差异有统计学意义（P〈0.05）;Dex2与Remif组比较,差异无统计学意义（P〉0.05）。结论右美托咪定能降低丙泊酚靶控输注意识消失的Cp50,且与剂量相关,1μg/kg的右美托咪定与靶浓度为2.0 ng/ml的瑞芬太尼作用相当。

Objective To explore the effect of different dosage of dexmedetomidine on propofol CpSO under general anesthesia with propofol TCI. Methods Seventy-four ASA Ⅰ-Ⅱ patients aged 18-65 years old with body weight index（BMI） 18-30 kg/m2 undergoing the selective limb surgery. The patients were randomly divided into 4 groups：control group （ C group, n = 18 ） , threated with propofol alone; remifentanil group（ R group, n = 18 ）, propofol plus remifentanil target plasma concentration of 2.0 ng/ml; dexmedetomidine group, propofol plus dexmedetomidine 0.5 μg/ml （ D1 group, n = 19 ） and 1.0 μg/ml （ D2 group, n = 20）. The patients awareness was observed until propofol plasma concentration and effect site concentration was equilibrium. According to the patients body movement in response ,0.5 g/ml of propofol Cp was increased or decreased. CpS0 of propofol in each group was calculated using＇ up and down＇ method. Results No differences were found in the demographic data among the four groups. Cp 50 of propofol was （ 3.50 ± 0. 27 ） μg/ml, （2.33 ±0.20） μg/ml, （3.08 ±0.26） μg/ml and（2.42 ±0.26） μg/ml in patients of C,R,D1 and D2 groups,respectively. Cp 50 of propofol had significantly deceased in R, D1 and D2 groups when compared with C group（P 〈 0.05 ）. Cp50 in D2 group was lower than that in Dl group （P 〈 0.05）. Conclusion Our study shown that dexmedetomidine is able to reduce propofol CpS0 during successfully inserted the laryngeal mask under general anesthesia, and the effect of dexmedetomidine 1.0 μg/kg is similar with remifentanil 2.0 ng/ml.