肥胖患者罗库溴铵的给药剂量应按理想体重还是校正体重计算

背景对于肥胖患者，药代动力学参数显示，应按照患者的理想体重计算罗库溴铵给药剂量，但此方生却可能延长罗库溴铵起效时间或不能满足插管条件。本研究按不同的校正体重将患者分成3组，并分别按照校正体重计算罗库溴铵给药剂量，比较3组中罗库溴铵的起效时间、插管条件和药物持续时间。方法将51例择期行腹腔镜胃束带减容术和胃转流术的肥胖患者随机分成3组，平均体重指数为44（34-72）kg／m^2，分别按照理想体重（IBW组，n=17）、理想体重加超标体重的20％[校正体重（CBW）20％组，n=17]、理想阵重加起标体重的40％（CBW40％组，n=17）计算罗库溴铵给药剂量（0．6mg／kg）．所有患者都采用丙泊酚-瑞芬太尼复合麻醉。一次静注丙泊酚200mg并以5mg·kg^-1·h^-1泵注维持麻醉，瑞芬太尼则以1．0μg·kg^-1·min^-1的速度维持输注，2种药物均采用CBW40％组的校正体重计算给药量。采用TOF（4个成串刺激）监测神经肌肉功能，首要观察指标为罗库溴铵持续时间，即4个成串神经刺激中第4个肌颤搐的恢复时间。结果IBW组、CBW20％组和CBW40％组罗车溴铵持续时间分别为32（18～49）分钟、38（25～66）分钟和42（24—66）分钟，IBW组和CBW40%组间差异有统计学差异（P=0．001）：而在各组罗库溴铵的起效时间（分别为85、84和80秒）和注药后90秒内的插管条件差异无统计学意义。结论对于行胃束带减容术和胃转流术的肥胖患者，按照理想体重给予罗库溴铵后其持续时间短，不会明显延长药物的起效时间，也不会影响插管条件。

BACKGROUND： Pharmacokinetic studies in obese patients suggest that dosing of rocuronium shouki be based on ideal body weight （IBW）. This may, however, result in a prolonged onset time or compromised conditions for tracheal inmbation. In this study, we compared onset time, conditions for tracheal intubation, and duration of action in obese patients when the intubation dose of rocuronium was based on three different weight corrections. METHODS： Fifty-one obese patients, with a median （range） body mass index of 44 （34 -72） kg/m^2, scheduled for laparoscopic gastric banding or gastric bypass under propofol-remifenmnil anesthesia were randomized into three groups. The patients received rocuronium （0.6 mg/kg） based on IBW （1BW group, n = 17）, IBW plus 20% of excess weight （corrected body weight [ CBW] 20% group, n = 17）, or IBW plus 40% of excess weight （CBW40% group, n = 17）. Propofol was administered as a bolus of 200 ng and an infusion at 5 mg· kg^-1·h^-1~ and remifentanil was administered at 1.0 μg ·kg^-1·min^-1, both according to CBW40%. Neuromuscular function was monitored with train-of-four nerve stimulation and acceleromyography. The primary end point was duration of action, defined as time to reappearance of the fourth twitch in train-of-four. RESULTS： The median （range） duration of action was 32 （18 -49）, 38 （25 - 66）, and 42 （24 - 66） min in the IBW, CBW20%, and CBW41）% groups, respectively （P = 0. 001 for comparison of the 1BW and CBW40% group）. There were no significant differences in onset time （85 vs 84 vs 80 s） or in intubation conditions 90 s after administration of rocuronium. CONCLUSIONS： In obese patients undergoing gastric banding or gastric bypass, rocuronium dosed according to IBW provided a shorter duration of action without a significantly prolonged onset time or compromised conditions for tracheal intubation.