不同剂量右美托咪定对靶控麻醉丙泊酚Cp50的影响

Effects of Different Dosage of Dexmedetomidine on Propofol Cp50 under General Anesthesia with Propofol TCI

目的比较不同剂量右美托咪定对丙泊酚靶控麻醉下成功插入喉罩丙泊酚Cp50的影响。方法选择ASA分级Ⅰ～Ⅱ级，年龄18～65岁，体质量指数18～30kg·m-2，行择期骨科四肢手术患者74例。患者均知情同意并签署知情同意书，随机分为4组：丙泊酚组（P组，／1=21）；瑞芬太尼（2．0ng／mL）丙泊酚组（R组，n=18）；右美托咪定（0．5μg／kg）±丙泊酚组（D1组，n=16）；右美托咪定（1．0μg／kg）±丙泊酚组（D2组，n=16）。待丙泊酚血药浓度与效应室浓度达到平衡时插入喉罩。采用改良的上下交叉点法根据患者的体动反应增加或减少下一个患者丙泊酚（0．5μg／mL）＆浆靶浓度，计算丙泊酚的Cp50值。结果4组患者的年龄、身高、体质量、性别构成比、麻醉诱导前心率、平均动脉压、BIS值、手术类别比较均无统计学差异（P〉0．05）。4组患者诱导后与诱导前比较心率、平均动脉压、BIS值均有明显下降（P〈0．05），但4组间比较并无统计学差异（P〉0．05）。P组、R组、D1组及D2组丙泊酚Cp50分别为（4．86±0．40）μg／mL、（2．42±0．33）μg／mL、（3．94±0．63）μg／mL、（2．44±0．27）μg／mL。与P组比较，R，D1和D2组的丙泊酚Cp50明显降低（P〈0．05）；与D1组比较，D2组Cp50值明显降低（P〈0．05）。结论右关托咪定能有效降低插入喉罩时丙泊酚的Cp50．1．0μg／kg右关托咪定与靶浓度为2．0ng／mL的瑞芬太尼相当。

Objective To study the effect of different dosage of dexmedetomidine on propofol Cp50 under general anesthesia with propofol TCI. Methods Seventy four ASA I-II patients aged 18-65yr with body weight index 18-30 kgm-1 undergoing the selective limb surgery. The patients were randomly divided into 4 groups：propofol group （P group, n --21 ）：threated with propofol alone ;Alpharemifentanil group （R group, n =18）：pmpofol plus remifentanil target plasma concentration of 2.0 ng/mL;dexmedetomidine group ：propofol plus dexmedetomidine 0.5μg/kg （D1 ,n =16） and 1 μg/kg （D2,n =16）. Laryngeal mask to be insert until propofol plasma concentration and effect-site concentra- tion is equilibrium. According to the patient＇s body movement in response to increase or to decrease 0.5 μg/mL of propofol Cp. 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 4.86±0.40 μg/mL, 2.42±0.33μg/mL, 3.94±0.63 μg/mL and 2.44±0.27 μg/mL in P, R, D1 and D2 group,respectively;it was significantly deceased in R,D1 and D2 groups as compared with P group （P 〈 0.05）. Cp50 in D2 group was low- er that in D1 group （ P 〈 0.05 ）. Conclusion Our study shown that dexmedetomidine able to reduce propofol CpS0 during successfully in- serted the laryngeal mask under general anesthesia, the effect of dexmedetomidine 1.0 txg/kg to be quite with remifentanil 2.0 ng/mL.