体外循环对红细胞流变学特性和形态的影响

Changes of Morphology and Deformability of Erythrocytes in Cardiac Surgery with Cardiopulmonary Bypass

目的观察体外循环(CPB)时间超过120min时对红细胞变形能力的影响。方法 20例择期心脏手术患者,分别在术前、CPB 60min、120min和结束时测定红细胞的流变学特性,术前和CPB结束时的血浆游离血红蛋白的水平。结果红细胞最大变形指数、综合变形指数、小变形指数在CPB 60min时均明显降低(P<0.01),之后三者都有所恢复;至CPB 120min时,最大变形指数、综合变形指数仍低于术前水平(P<0.01),而小变形指数已基本接近术前水平;CPB结束时,最大变形指数仍低于术前水平(P<0.05),综合变形指数、小变形指数已基本接近术前水平。红细胞形态在CPB中发生了轻度畸形变,血浆游离血红蛋白在CPB结束时明显升高。结论CPB虽然可导致红细胞的损伤及血浆游离血红蛋白水平升高,并可引起红细胞形态的轻度畸形变,但对红细胞群体的变形能力没有明显不利影响。

OBJECTIVE To observe the dynamic changes of morphology and deformability of erythrocytes in cardiopul-monary bypass (CPB) lasted more than 120 minutes. METHODS 20 patients who underwent cardiac surgery with CPB were enrolled in this study. The duration of CPB was over 120 minutes in all cases. The morphology and deformability of erythrocytes were measured before operation, at 60 minutes, 120 minutes and the end of CPB. The deformability of erythrocytes was measured with ektacytometry . The morphology of erythrocytes was observed with scanning electron microscope. In additional, The concentration of plasma hemoglobin was measured before operation and at end of CPB. RESULTS Maximum deformability, integrate deformation index and small deformation index greatly decreased at 60 minutes of CPB ( P < 0.01), then gradually restored. Maximum deformability and integrate deformation index yet were lower than that before operation at 120 minutes of CPB. At the end of CPB, there were no significant differences between preoperative integrate deformation index and small deformation and postoperative parameters. However, maximum deformability was still lower than that before operation ( P < 0.05). There was no significant change of orientation index during CPB. The morphological examination indicated that normal erythrocytes underwent an ecchinocytic shape transformation during CPB. The concentration of plasma hemoglobin increased significantly at the end of CPB ( P < 0. 01 ). CONCLUSION During CPB that lasted more than 120 minutes, there were some erythrocytes destroyed that can be demonstrated by increase of plasma hemoglobin. There were some changes of morphology of erythrocytes. However, the deformability of major erythrocytes was not affected.