Effects of cardiopulmonary bypass with mild hypothermia on pharmacodynamics of rocuronium in infants undergoing cardiac surgery / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of cardiopulmonary bypass (CPB) with mild hypothermia on the pharmacodynamics of rocuronium in infants undergoing cardiac surgery.Methods Fifty ASA Ⅰ or Ⅱ and NYHA class Ⅰ or Ⅱ infants,aged 6 months-3 yr,weighing6-15 kg,undergoing repair ofventricular septal defect or atrial septal defect under CPB,were randomly divided into 2 groups ( n =25 each)profound hypothermia group and mild hypothermia group.The target temperature was controlled at 28-30 ℃ during CPB in profound hypothermia group,and at 32-34 ℃ during CPB in mild hypothermia group.Neuromuscular block was assessed by TOF-stimulation of ulnar nerve using with TOF-Watch accelerometer.Anesthesia was induced with midazolam O.1 mg/kg,propofol 2 mg/kg,fentanyl 6-8 μg/kg and rocuronium 600 μg/kg,and maintained with intermittent iv boluses of fentanyl and midazolam.The patients was tracheal intubated and mechanically venti1ated when the maximal depression of T1 was achieved.PETCO2 was maintained at 30-40 mm Hg.When T1 returned to 75％ of the control twitch,rocuronium 200 μg/kg was injected intravenously.The onset time,maximal N-M block time,clinical muscle relaxation time,and recovery index were recorded before CPB,during CPB and after CPB.Results Compared with profound hypothermia group,the onset time,maximal N-M block time and clinical muscle relaxation time were significantly shortened during CBP in mild hypothermia group ( P ＜ 0.05).Conclusion Compared with profound hypothermic CBP,mild hypothermic CBP can shorten the onset time and muscle relaxation time of rocuronium in infants undergoing cardiac surgery.