术前输注谷氨酰胺对体外循环下心脏手术患者的心肌保护效果

Efficacy of preoperative infusion of glutamine for myocardial protection in patients undergoing cardiac surgery with cardiopulmonary bypass

目的评价术前输注谷氨酰胺对体外循环下心脏手术患者的心肌保护效果。方法拟行体外循环下瓣膜置换术和／或冠状动脉旁路移植术的患者40例，年龄18～80岁，ASA分级I一Ⅲ级，心功能分级I一Ⅲ级，左室射血分数≥40％，采用随机数字表法分为2组：谷氨酰胺组（G组，n=18）于术前24h和术前1h分别静脉输注谷氨酰胺0．4g／kg（2ml／kg）与5倍容量（10ml／kg）的8．5％复合氨基酸混合液，经1h输完；对照组（C组，n=22）于术前24h和术前1h分别静脉输注等容量的乳酸钠林格氏液12ml／kg，经1h输完。于切皮前、术毕、术后20h时抽取静脉血样，采用酶联免疫吸附法检测血浆丙二醛（MDA）浓度。于切皮前、心脏复跳后6、20h时抽取静脉血样，采用化学发光法测定血浆心肌肌钙蛋白I（cTnI）浓度。记录心脏复跳和心室起搏情况、术后机械通气时间、ICU停留时间、ICU期间多巴胺和多巴酚丁胺用量、术后总住院时间、心力衰竭、呼吸功能衰竭、肝肾功能异常等不良事件发生情况和住院期间病死情况。结果G组15例、C组18例完成研究。与C组比较，G组心脏复跳后20h时血浆cTnI浓度降低，术前、术毕和术后20h时血浆MDA浓度降低，ICU期间多巴胺用量降低（P〈0．05或0．01），心脏复跳方式构成比、复跳后心室起搏率、术后机械通气时间、ICU期间多巴酚丁胺用量、ICU停留时间和术后总住院时间、术后不良事件发生率和病死率差异无统计学意义（P〉0．05）。结论术前输注谷氨酰胺虽可抑制氧化应激反应，减轻体外循环下心脏手术患者心肌损伤，但临床意义不明显。

Objective To evaluate the efficacy of preoperative infusion of glutamine for myocardial protection in patients undergoing cardiac surgery with cardiopulmonary bypass （CPB）. Methods Forty patients, aged 18-80 yr, of ASA physical status I -m （NYHA I -Ⅲ） , scheduled for elective cardiac valve replacement and/or coronary artery bypass grafting with CPB, with their left ventricular ejection fraction ≥40%, were enrolled in the study. The patients were randomly divided into 2 groups using a random number table： glutamine group （group G, n = 18） and control group （group C, n = 22）. In group G, the mixture of glutamine 0.4 g/kg （2 ml/kg） and 8.5% compound amino acid （ 10 ml/kg） was infused over 1 h starting from 24 and 1 h before surgery. Lactated Ringer＇ s solution 12 ml/kg was infused intravenously over 1 h starting from 24 and 1 h before surgery. Before skin incision, at the end of surgery and at 20 h after surgery, venous blood samples were collected for detection of malondialdehyde （MDA） concentrations using ELISA. Before skin incision and at 6 and 20 h after restoration of spontaneous heart beat, venous blood samples were collected to determine the plasma concentration of cardiac troponin I （cTnI）.The restoration of spontaneous heart beat, ventricular pacing, postoperative ventilation time, duration of ICU stay, consumption of dopamine and dobutamine during ICU stay, total postoperative length of hospital stay, adverse events such as heart failure, respiratory failure, abnormal hepatic and renal function, and the mortality rate during hospital stay were recorded. Results A total of 15 patients in group G and 18 patients in group C completed the study. Compared to group C ; the plasma cTnI concentration at 20 h after restoration of spontaneous heart beat, plasma MDA concentration before operation, at the end of operation and at 20 h after operation, and consumption of dopamine during ICU stay were significantly decreased in group G. There was no significant difference between the two groups in the constituent ratio of mode of spontaneous heart beats, rate of ventricular pacing after spontaneous heart beats, postoperative duration of mechanical ventilation, consumption of dobutamine during ICU stay, duration of ICU stay, postoperative length of hospital stay, incidence of postoperative adverse effects, and mortality rate. Conclusion Although preoperative infusion of glutamine can inhibit oxidative stress response and attenuate postoperative myocardial injury, it provides no clinical significance in the patients undergoing cardiac surgery with CPB.