中枢神经系统损伤与保护方法的评估

Assessment of Cerebral Injury and Effcct Different of Protection on Brain during Cardiopulmonary Bypass

目的 通过系列的动物实验及临床观察 ,探讨如何对心脏手术围术期中枢神经系统的损伤程度以及不同方法的脑保护效果进行合理的评估。方法 对体外循环 (CPB)、停循环以及上腔静脉逆行灌注 (RCP)期间的血液灌注进行观察 ,检测组织生化酶学和活体脑组织钙离子荧光强度 ,并进行组织病理及电镜检测。采用便携式眼底镜在临床手术患者进行前瞻性观察。结果 眼底血管造影、彩色多普勒超声波检查和同位素99mTc -ECD均证实 :逆行灌注期间的大脑灌注与单纯停循环相比 ,RCP能够明显减轻停循环后一氧化氮 (NO)的产生量以及钙超载的发生 ,维持组织较高的Na+-K+ATP酶、超氧化物歧化酶、谷胱甘肽过氧化物酶活力 ,较少丙二醛产生 ,从而减轻停循环后神经细胞的缺血缺氧程度。便携式眼底镜在临床手术患者同样观察到逆灌期间的血液灌注。结论 激光共聚焦显微镜技术和核磁共振仪检测脑组织中钙超载以及NO产生量、多种酶学检测结合组织病理检查可作为动物实验中对神经细胞损伤程度评价的手段。同位素99mTc -ECD、眼底血管荧光造影、彩色多普勒超声波检查可以评定脑组织的灌注状况 。

OBJECTIVE Investigate apt methods for assessment of cerebral injury and effect of different protection on brain retrospectively. METHODS Animal models of deep hypothermic circulatory arrest (DHCA) and retrograde cerebral perfusion (RCP) during DHCA were established, cerebral blood perfusion was observed by fundus fluorescein angiography (FFA), color Doppler sonography and isotope scanning. The concentration of Na +-K + ATPase, superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), malondialdehyde (MDA) were measured. The level of nitric oxide (NO) was detected by nuclear magnetic resonace (NMR) and calcium fluorescent intensity of vital brain slice by Laser Confocal Scanning Microscope (LCSM). Some preliminary clinical observations were made with ophthalmoscope. RESULTS FFA, color Doppler sonography and isotope scanning ( 99m Tc-ECD) all demonstrated that cerebral perfusion existed during RCP. Compared with DHCA, RCP could attenuate cerebral injury after DHCA through maintaining higher concentration of Na +-K + ATPase, SOD, GSH-PX and decreasing production of MDA, NO and calcium overload. CONCLUSION In animal experiment cerebral injury can be assessed by measurement of calcium fluorescent intensity of vital brain slice, production of NO and some biochemical markers. FFA, color Doppler sonography and isotope scanning are practicable for monitoring cerebral perfusion in clinics.