不同剂量右美托咪定对依托咪酯致患者意识消失ED95的影响

Effects of different doses of dexmedetomidine on ED95 of etomidate for loss of consciousness

目的探讨不同剂量右美托咪定对依托咪酯致患者意识消失ED95的影响。方法择期行全麻手术患者120例,男69例,女51例,年龄20~60岁,体重58~79 kg,ASAⅠ或Ⅱ级。按照随机数字表法将患者分为三组:依托咪酯组(E组)、依托咪酯复合右美托咪定0.5μg/kg组(ED1组)和依托咪酯复合右美托咪定1.0μg/kg组(ED2组)。E组按照偏性掷币(BCD)序贯法给予依托咪酯,首剂量为0.04 mg/kg,相邻剂量差0.04 mg/kg。ED1组和ED2组先给予负荷剂量的右美托咪定0.5μg/kg和1.0μg/kg,给药时间为10 min,之后按照BCD序贯法给予依托咪酯。应用保序回归及合并相邻者算法计算依托咪酯致患者意识消失的ED95及其95%可信区间(CI)。观察患者不良反应发生情况。结果 E组依托咪酯ED95及其95%CI为0.222(0.197~0.255)mg/kg,ED1组为0.158(0.121~0.186)mg/kg,ED2组为0.138(0.112~0.168)mg/kg。ED1组和ED2组ED95明显低于E组(P<0.05)。ED2组心动过缓的发生率明显高于E组和ED1组(P<0.05)。结论预注右美托咪定0.5μg/kg和1.0μg/kg可明显降低依托咪酯致患者意识消失的ED95,但右美托咪定1.0μg/kg有增加心动过缓的风险。

Objective To determine the effects of different doses of dexmedetomidine on ED95 of etomidate for loss of consciousness. Methods A total of 120 patients, 69 males and 51 females, aged 20-60 years, weighing 58-79 kg, ASA physical status Ⅰ or Ⅱ, undergoing general anesthesia were enrolled. These patients were randomly allocated into three groups: receiving etomidate alone(group E), etomidate combined with dexmedetomidine 0.5 μg/kg for intravenous premedication(group ED1), etomidate combined with dexmedetomidine 1.0 μg/kg for intravenous premedication(group ED2). For group E, the etomidate dosage was determined using the biased coin design(BCD) up-and-down sequential method. The first patient was administered with etomidate of 0.04 mg/kg. For groups ED1 and ED2, 0.5 μg/kg and 1.0 μg/kg of dexmedetomidine were respectively injected for more than 10 minutes before the etodidate dosage, this was determined using the BCD up-and-down sequential method. ED95 of etomidate for loss of consciousness of every group was determined by the isotonic regression with pooled adjacent violators algorithm separately. The bootstrap was used to estimate the 95% confidence interval(CI) of ED95. Results ED95 and the 95%CI of etomidate for loss of consciousness was 0.222 mg/kg(0.197-0.255 mg/kg) in group E, 0.158 mg/kg(0.121-0.186 mg/kg) in group ED1 and 0.138 mg/kg(0.112-0.168 mg/kg) in group ED2, respectively. The ED95 of etomidate for loss of consciousness in groups ED1 and ED2 were significantly lower than that in group E(P<0.05). Compared with groups E and ED1, the incidence of bradycardia was higher in group ED2(P < 0.05). Conclusion Dexmedetomidine 0.5 or 1.0 μg/kg for intravenous premedicationcan significantly reduce the ED95 of etomidate for loss of consciousness, however dexmedetomidine 1.0 μg/kg may cause more bradycardia.