体外循环低温室颤对犬肺功能的影响

Effect of hypothermic ventricular fibrillation on lung function in dogs undergoing cardiopulmonary bypass

目的:探讨体外循环低温室颤对犬肺功能的影响.方法:健康成年杂种犬14只随机分为实验组和对照组,每组7只.全麻,右侧第四肋间进胸,常规建立体外循环(CPB),心尖部左心引流.实验组:不阻断升主动脉,血流降温到28℃,心包腔内注入4℃生理盐水诱导室颤;对照组:阻断升主动脉,经主动脉根部灌注停跳液.检测不同时间点血清IL-8浓度、肺顺应性,观察肺组织形态学改变,比较体外循环条件下低温室颤对肺脏的损伤程度.结果:实验组与对照组的血清IL-8的浓度水平比较差异有统计学意义(P<0.05),各时间点之间也存在差异(P<0.05).两组在T1时间点的IL-8浓度无明显差别,转机后均开始升高,且均在T3时间点达到高峰,并于T4时间点逐渐下降,但仍然高于T1时间点水平.肺组织形态学显示:实验组较对照组肺组织病理损伤减轻;肺顺应性:实验组与对照组肺顺应性比较差异有统计学意义(P<0.05),各时间点之间也存在差异(P<0.05).两组在T1时间点肺顺应性无明显差别,转机后均开始降低,且均在T3时间点达到高峰,并于T4时间点逐渐恢复,但仍然低于T1时间点水平.结论:体外循环中应用低温室颤技术可降低组织的损伤程度,对肺功能有保护作用.

AIM： To evaluate the effect of hypothermic ventricular fibrillation on lung function in dogs undergoing cardiopulmonary bypass （ CPB ）. METHODS： Fourteen healthy adult dogs were randomly divided into 2 groups （n = 7 per group） ： hypothermic fibrillation group （ experimental group） and cold crystalloid cardioplegia group （control group）. Operation was performed through the fourth right intercostal space under general anesthesia, which was followed by systemic hypothermia to 28℃. A standard CPB was performed in the control group. Ventricular fibrillation was induced by injecting 4℃-normal saline into pericardial cavity. The concentration of serum IL-8 was measured by ELISA before CPB, at the 1st hour during CPB, at the end of CPB and at the 1st hour after CPB. Lung specimens were obtained before CPB and at the end of CPB. Lung compliance was used to evaluate lung function. RESULTS： The concentration of serum IL-8 in the 2 groups was significantly different（P〈0.05）, so was it at various time points （P〈0.05）. No difference was found in the 2 groups before CPB. The serum IL-8 level went up gradually after the initiation of CPB and reached its peak at the end of CPB. IL-8 level decreased at the 1st hour after CPB, but it was still higher than that before CPB. Compared with that in the control group, the histopathological lesion in lungs was less severe in the experimental group. No statistical difference of lung compliance was found between the experimental and control groups before CPB, but significant difference was found at various time points, between the two groups （ P 〈0. 05） after CPB. The lung compliance went down gradually after the initiation of CPB and reached the lowest point by the end of CPB. CONCLUSION. Compared with normal CPB, hypothermic ventricular fibrillation under cardiopulmonary bypass reduces the lesion of tissues and has some protective effects on lung function.