体外循环中白细胞对肺损伤机制及白细胞过渡的肺保护作用

肺损伤为体外循环术后常见的并发症之一，血液与体外循环管道接触，能够活化补体，激活白细胞，白细胞激活后黏附于血管内皮细胞或进入肺组织，释放具有趋化作用的炎性介质及代谢产物，如蛋白酶，氧自由基和花生四烯酸等在肺损伤中起着重要作用，动物实验及临床应用白细胞过滤器在体外循环中对白细胞进行过滤，肺血管阻力明显降低，血氧饱和度，动脉血氧分压升高，尤其对术前缺氧越重和体外循环时间越长的患者作用越明显，因此，在体外循环中进行白细胞过滤能够减轻其对肺的损伤，起到肺保护作用。

The Mechanism of Lung Injury by Leukocyte During Extracorporeal Circulation and Protective Effects of Leukocyte Depletion on Lung Function

Lung injury was one of the most complications after extracorporeal circulation. As a result of blood exposure to the surface of the extracorporeal circulation circuit, the complements and leukocytes were activated. The activated neutrophil adhered to endothelial cells and released many inflammatory mediators, as protease, oxygen free radicals, arachidonic acid metabolites. All of these inflammatory mediators caused lung injury. In vivo and in vitro, many studies demonstrated that leukocyte depletion in extracorporeal circulation of heart operation could reduce lung injury and improve lung function. Leukocyte depletion could reduce pulmonary resistance, particularly effective in patients with a low preoperative oxygenation capacity and in those for whom an extended period of extracorporeal circulation was required.