体外循环心脏手术术中影响听觉诱发电位相关因素分析

目的听觉诱发电位（AEP）应用于体外循环心脏手术病人，探讨体外循环（CPB）中可能影响AEP的因素。方法择期心脏瓣膜置换术患者20例，咪唑安定、乙咪酯、芬太尼、罗库溴铵诱导气管插管，靶控输注（TCI）丙泊酚、瑞芬太尼维持麻醉，设立麻醉与体外循环前后14个观察点，采用自身对照观察AEP变化和CPB时灌注流量（AQ）、灌注压（PP）、中心静脉压（CVP）、鼻咽温（Temp1）、直肠温（Temp2）对AEP的影响。术后访视病人。结果麻醉诱导后AEP迅速下降（P〈0．01），切皮、锯胸骨、主动脉插管及转机前AEP升高（P〈0．05）。CPB期间，AEP降低并与心脏停搏鼻温最低时达谷值（P〈0．05）。恢复循环后AEP值上升，停机时恢复CPB前水平（P〈0．05）。无术中知晓发生。结论AEP能及时准确的反映体外手术各时期的麻醉镇静深度变化，有效预防术中知晓。CPB期间，低温、低灌注压对AEP抑制明显。

Effect of open cardiac surgery around cardiopulmonary bypass on auditory evoked potential

Aim Auditory evoked potential (AEP) monitors patients in heart valve replacement undergoing cardiopulmonary bypass(CPB).To analyze the effect of the factor related to CPB on AEP.Methods Twenty ASA Ⅱ～Ⅲ patients undergone elective heart valve replacement were studied.The patients were induced with midazolam,etomidate,fentanyl and rocuronium used for neuromuscular block.Anesthesia was maintained with midazolam,fentanyl by target-controlled infusion(TCI).AEP,MAP,HR were recorded at 14 different time points and the statistics of CPB were also recorded.The patients were visited after recovery from anesthesia.Results AEP decreased significantly greater induction of anesthesia (P<0.01).During incision,sternotomy and aortic cannulation,AEP increased (P<0.05).The decrease in AEP was significantly greater during CPB especially in hypothermia with heart arrest (P<0.05).After rewarming and restoring heart beats,AEP began to increase and was elevated to the level before CPB in the end (P<0.05).All patients were detected no awareness during operation.Conclusion The depth of anesthesia in cardiac operation with CPB can be monitored promptly and precisely by AEP.Hypothermia,hypotension and non-pulsating perfusion markedly depressed AEP during CPB.