体外循环下异丙酚靶控输注系统的准确性

Accuracy of target-controlled infusion of propofol for cardiac valve replacement performed under cardiopulmonary bypass

目的评价体外循环下异丙酚靶控输注系统的准确性。方法择期体外循环下行心脏瓣膜置换术患者20例，ASAⅡ或Ⅲ级，年龄25—64岁，体重50～70kg。静脉注射咪达唑仑、芬太尼和维库溴铵行麻醉诱导，气管插管后机械通气。麻醉维持采用嵌入Tackley药代动力学参数的靶控输注系统输注异丙酚至术毕，血浆靶浓度为1μg／ml。于体外循环前（TI）、体外循环开始后1、5、10、20、40、60min（T2-7）、体外循环结束后5、10min（R8,9）时采集桡动脉血样3ml，采用反相高效液相色谱法测定血浆异丙酚浓度，计算异丙酚靶控输注系统的偏离度、精确度、摆动度及分散度。结果，T1时异丙酚实测浓度高于血浆靶浓度（P〈0．05），T2～4时异丙酚实测浓度与血浆靶浓度差异无统计学意义（P〉0．05），T5～9时异丙酚实测浓度高于血浆靶浓度（P〈0．05）。异丙酚靶控输注系统的偏离度为21％、精确度为29％、摆动度为21％及分散度为-0．06％／h。结论心脏手术患者体外循环时，采用嵌入Tackley药代动力学参数的异丙酚靶控输注系统的准确性超出临床可接受范围。

Objective To investigate the performance of target-controlled infusion （TCI） of propofol for cardiac valve replacement performed under cardiopulmonary bypass （CPB）. Methods Twenty ASA Ⅱ or Ⅲ patients aged 25-64 yr weighing 50-70 kg undergoing cardiac valve replacement under CPB were enrolled in this study. Anesthesia was induced with intravenous midazolam, fentanyl and roeuronium and maintained with intravenous midazolam infusion （0.05-0.1mg·kg^-1·h^-1 ）, TCI of propofol （target plasma concentration was set at 1 μg/ml）, intermittent iv boluses of fentanyl and iv reeuronium infusion （0.05-0.1 mg·kg^-1·h^-1 ）. Propofol was administered with a specific TCI system incorporating the Tackley pharmaeokinetic parameters. Blood samples were obtained from radial artery before CPB （T1 ,baseline）, at 1, 5, 10, 20, 40, 60 min of CPB （T2,7） and 5,10 rain after CPB （T8,9 ） for measurement of propofol plasma concentration by HPLC. Median prediction performance error （MDPE）, median absolute performance error （MDAPE）, wobble and divergence of propofol TCI system were calculated. Results The measured plasma concentrations of propofol were significantly higher at T1 than the target plasma concentration （Cp） but there were no significant differences between the measured plasma concentrations and Cp of propofol at T2-4 . The measured plasma concentrations of propofol were significantly higher than Cp at T5-9. The MDPE, MDAPE, wobble and divergence of propofol TCI system were 21%, 29%, 21% and -0.06%/h respectively. Conclusion The accuracy of the TCI system incorporecting the Tackley pharmacokinetic parameters exceeds the clinically acceptable scopein patients undergoing cardiac valve replacement under CPB.