体外循环心脏直视手术中心脏缺血预处理对肺的保护作用

通过对２０例病人在体外循环心内直视手术过程中进行心脏缺血预处理，观察其对肺缺血再灌注后的影响。结果表明：心脏缺血预处理对肺亦具有保护作用，其作用机制可能与抑制了中性粒细胞（ＰＭＮ）在肺内聚集与激活及减少了氧自由基的产生有关。

The protective effects of cardiac ischemic preconditioning on lung in cardiac operation with cardiopulmonary bypass]

Twenty direct vision intracardial operation patients were divided into two groups randomly. After cardiopulmonary bypass, ten patients were treated with myocardial ischemic preconditioning. The aorta were clamped for 3 minutes and released for 3 minutes (Group IP). Another ten patients were not treated with ischemic preconditioning (Group C), only underwent 6 minutes cardiopulmonary bypass. Then the aorta were clamped and intracardial operation were done. The left atrium blood and lung tissue were collected just after thoractomy and half an hour after cardiac reperfusion in both groups. RESULTS: (1) The numbers of polymorphonuclear (PMN) of the two groups were increased significantly after cardiopulmonary bypass (P < 0.01). (2) The number of PMN and SOD, PaO2 contents were significantly higher in Group IP than in Group C (P < 0.05). (3) The numbers of PMN in lung interstitum under microscopy were less in Group IP than in Group C. (4) MDA contents were less in Group IP than in Group C (P < 0.05). (5) Histological finding showed less damage in Group IP than in Group C. It is evident that cardiac ischemic preconditioning could protect lung against ischemia reperfusion injury. The possible mechanisms are that ischemic preconditioning inhibites the accumulation and activation of PMN in lung tissue and reduces the production of oxygen free radicals.