七氟醚后处理对体外循环犬肺保护的作用

Protective effects of sevoflurane postconditioning on pulmonary function during cardiopulmonary bypass in dogs

目的探讨七氟醚后处理对体外循环(CPB)犬肺组织缺血-再灌注损伤(LIRI)的保护作用。方法健康成年杂种犬12只,随机分为两组(n=6),左肺缺血再灌注组(C组)、七氟醚后处理组(Y组)。两组犬麻醉后行双腔气管插管机械通气,股动、静脉穿刺置管测平均动脉压(MAP)及中心静脉压(CVP),开胸并建立犬CPB。C组犬左肺行缺血再灌注,Y组左肺缺血再灌注后行七氟醚后处理。分别于CPB前(T1)、开放左肺动脉时(T2)及停机后2h(T3)取肺组织HE染色观察形态学变化并进行病理评分,取股动脉血行动脉血气分析并计算氧合指数(OI)、呼吸指数(RI)和动态肺顺应性(Cd)。结果 (1)光镜观察:两组犬肺组织破坏程度随时间推移而增加,两组T1、T2时点肺组织无明显差异;T3时点C组肺组织破坏最为严重,Y组肺组织破坏程度明显低于C组;(2)病理学评分:两组T3时点病理学评分明显高于T1、T2时间点,Y组病理评分明显低于C组(P<0.05);(3)呼吸参数变化:随时间推移两组OI和Cd明显降低而RI明显升高,T3时间点Cd和OI,Y组明显高于C组(P<0.05),而RI,Y组明显低于C组(P<0.05)。结论七氟醚后处理可提高体外循环犬的OI、Cd,降低犬RI,对犬体外循环导致的肺损伤有一定的保护作用。

Objective To investigate the protective effects of sevoflurane post -conditioning on pulmonary function during Lung ischaemia reperfusion injury （LIRI） on cardiopulmonary bypass （CPB） in dogs.Method Twelve dogs were randomly divided into two groups with six dogs in each group which were left lung ischaemia reperfusion injury group （C group） and sevoflurane postconditioning group （Y group）.All the dogs were in narctism by injecting pentobarbital sodium into cavum abdominis （25mg/kg） followed by tracheal intubation with artificial ventilation.The mean arterial pressure （MAP） and central venous pressure were measured after opening the femoral artery and femoral vein.Then ,the CPB model was established after opened chest in dogs.The animal model of the left lung ischemia reperfusion was established in two groups.Finally ,to postconditioning by sevoflurane in Y group.The specimen of left lung tissue were collected at T1 （before CPB） ,T2 （after the left pulmonary artery was occluded opened ） and T3 （after 2h of CPB） to immobilization storage and observe changes of pathology with light microscope and get patho-logical score.The specimen of arterial blood was collected to calculate oxygenation index （OI） and respiration index （RI） ,dynamic lung compliance （Cd）.Result The extent of damage to increase with time in lung tissue in light micro-scope.The results showed that there were no differences between two groups on T 1 ,T2 time points and the lung tis-sue was significantly undermined in T3C.The results also showed that the situation of T3Y group was obviously bet-ter than T3 C.The pathological section score of lung tissue was significantly higher at T 3 time point compared with T1 ,T2 time point（P〈0.05） ,The pathological section score was lower at T3 time point of Y group compared with C group（P〈0.05）.The change of respiration parameters shown that dynamic lung compliance （Cd） and oxygenation index （OI） was significantly decreased and respiration inde x （RI） was significantly increased with time in two groups.Dynamic lung compliance （Cd） and oxygenation index （OI） was higer at T3 time point of Y group compared with C group（P〈0.05） ,on the contrary ,respiration index （RI） was lower at T3 time point compared with C group （P〈0.05）.Conclusion Sevoflurane postconditioning can reduce the RI and enhance the OI and Cd to improve the pulmonary function after CPB in dogs.