靶控输注异丙酚对体外循环复温期脑代谢的影响

Effect of target controlled infusion of propofol on cerebral metabolism during rewarming period of cardiopulmonary bypass

目的观察靶控输注异丙酚对中低温体外循环（CPB）心内直视手术各时点脑代谢指标的变化，评价靶控输注异丙酚在体外循环复温期的脑保护作用。方法择期CPB下行心内直视手术患者40例，ASAⅡ或Ⅲ级，随机分为2组，A组（n=20）靶控输注异丙酚（1～2μg·mL^-1），B组（n=20）恒速输注咪唑安定0．10～0．20mg·kg^-1·h^-1。术中依据SNAP脑电指数（SI）值的变化，并参考血流动力学变化调整异丙酚靶浓度和咪唑安定输注速度，使SI值维持在（60±5）。术中分别于麻醉后5min（T1）、CPB开始5min（T2）、降温结束后5min（T3）、复温至鼻咽温37℃即刻（T4）、30min（T5）、60min（T6）从桡动脉和颈内静脉球部采集标本，分别行葡萄糖（Ga、Gjv）、乳酸（La、Ljv）测定，计算颈内静脉-动脉乳酸含量差（AVDL）、乳酸生成率（CLP）、颈内静脉-动脉血糖含量差（AVDG）、葡萄糖摄取率（CGU），并分别对以上指标进行统计学处理。结果AVDG、CGU2组之间均无明显差异（P〉0．05），AVDL、CLPT4、T5、T6B组明显高于A组（P〈0．05或0．01）。结论靶控输注异丙酚（1～2μg·mL^-1）在中低温体外循环复温期能改善脑代谢，具有一定的脑保护作用。

Objective To observe the change of cerebral metabolism at different phases of propofol given by target-controlled infusion （TCI） during mild hypothermic cardiopulmonary bypass （CPB）, and to evaluate cerebral protective effect of target-controlled propofol during rewarming period of CPB. Methods Forty consecutive ASA Ⅱ-Ⅲ patients undergoing elective cardiac surgery under mild hypothermic CPB were randomly divided into 2 groups. In group A the patients were given target controlled proprfol 1-2 μg · mL^-1, while in group B the patients were given midazolam 0. 10-0.20 mg·kg ^-1 · h^-1. SNAP index （SI） was maintained at （60±5） by adjustment. Blood samples were taken from radial artery and internal jugular vein 5 rain after anesthesia induction （T1）, 5 rain after beginning of CPB （T2）, 5 rain after finishing of hypothermia （T3）, nasopharyngeal temperature （NPT） reaching 37℃ 0 rain （T4）, 30 min （TS） and 60 min （T6）. All samples were measured lactate and glucose to calculate arterial-vein lactate difference （AVDL）, cerebral lactate production （CLP）, arterial-vein glucose difference （AVDG）, and glucose extraction rate （CGU）. All the above indexes were analyzed by statistics. Results The significant differences of AVDG and CGU were not seen between group A and group B （P〉0. 05） . AVDL and CLP were higher in group B than those in group A at T4, T5 and T6 （P〈0.05 or 0. 01）. Conclusion Target-controlled propofol （1-2 μg · mL^-1） can ameliorate cerebral metabolism , and play a role in the cerebral protection during rewarming period of cardiopulmonary bypass.