缺血预处理对体外循环犬肺损伤的保护作用

目的 探讨缺血预处理（IP）对体外循环（CPB）犬肺损伤的保护作用.方法 健康杂种犬N =12,随机均分为两组,对照组（C组）和IP组（Y组）,麻醉后行双腔气管插管,开胸建立CPB肺缺血再灌注损伤模型.C组在左肺行缺血再灌注,Y组在阻断左肺动脉前进行IP.于CPB前（T1）、阻断左肺动脉前（T2）、停机时（T3）、停机后2h（T4）取肺组织称湿、干重及行光镜学检查.在T1、T3、T4时点取动脉血行血气分析计算呼吸指数（RI）和氧合指数（OI）.结果 ①湿、干重比：组内随着时间的延长逐渐升高（P＜0.05）;组间Y组T3、T4时点明显低于C组（P＜0.05）;②病理学变化及评分：组内T3、T4时点病理评分明显高于T1时点（P＜0.05）.组间Y组T3、T4时点评分明显低于C组（P＜0.05）;③RI和OI的变化：组内随时间推移RI逐渐升高,OI则降低（P＜0.05）;组间Y组T3、T4时点RI明显低于C组,OI则相反（P＜0.05）.结论 IP可降低CPB犬RI,提高其OI,改善犬的肺功能,对犬CPB肺损伤有一定的保护作用.

Ischemic preconditioning effects on pulmonary function after cardiopulmonary bypass in dogs

Objective To explore the protective effect of ischemic preconditioning （IP） on pulmonary function of dogs after cardiopulmonary bypass （CPB）. Methods A total of 12 healthy mongrel dogs were randomly assigned to two groups： Control group （group C n = 6 ）, Ischemic preconditioning group （group Y n =6）. Two groups of dogs were injected anesthetic, then fixed and operated endotracheal in- tubation and established the model of lung ischemia - reperfusion injury after cardiopulmonary bypass. Group C received ischemia- reperfusion in left lung, and dogs in the group Y received the lung ische- mic preconditioning before blocking the left pulmonary artery. Samples of lung tissue were collected at T1 （before the CPB）, T2 （before blocking the pulmonary artery）, T3（end of CPB） , and T4（2 hours af- ter CPB）. The wet weight and dry weight of lung were recorded, and the lung histology was observed by optical microscopy. Samples of arterial blood were collected at T1 , T3, T4 time points for being used to calculate respiration index （RI） and oxygenation index （OI）. Results ①The wet and dry weight ratio of lung tissue gradually increased with time （P 〈 0.05 ）. and was significantly lower in Y group at T3 and T4 time point （ P 〈 0.05 ）. ②Pathological section score of lung tissue was significantly higher at T3 and T4 time point compared with T1 time point （ P 〈 0.05 ）. Pathological section score of lung tissue of Y group was significantly lower than C group at T3and T4time point （P 〈 0.05 ）. ③RI gradually in- creased with time, but OI was decreased （P 〈 0.05 ）. These alterations were ameliorated in Y group （ P 〈 0.05 ）. Conclusion Ischemic preconditioning can reduce the RI and increase OI and improve the pul- monary function after CPB in dogs.