在深低温停循环中小预充量体外循环的脑保护效果

目的 观察在深低温停循环中小预充量体外循环的脑保护效果.方法 将实验动物分为假手术组(S组)、小预充量组(L组)、大预充量组(H组),建立联合脑微透析和体外循环(CPB)的动物模型.实验中进行微透析取样和生理指标监测,结束后取脑组织作组织学检测,用高效液相色谱法和CMA600分析仪检测微透析样品.结果 实验中,H组所用多巴胺和碳酸氢钠的量高于L组[(2.07±0.63)mg＞(1.12±0.47)mg;(14±3)ml＞(7±3)ml,P＜0.05].检测显示,H组的乳酸/葡萄糖和乳酸/丙酮酸比值在体外循环后高于L组(12.63±0.44＞3.71±1.31;13.14±1.37＞3.82±1.41,P＜0.05);H组的谷氨酸水平在实验后期高于L组(6.02±0.65＞2.21±0.72,P＜0.05);H组脑组织损伤程度明显重于L组.结论 深低温停循环时,与大预充量比较小预充量体外循环有显著的脑保护作用.

Effects of deep hypothermic circulatory arrest with low priming volume on brain injury

Objective To investigate the neuroprotective effect of deep hypothermic circulatory arrest (DHCA) with low priming volume in a rabbit model. Methods Rabbits were randomized into three groups : low priming volume ( group L) , high priming volume ( group H ), and sham-operated group (group S). The rabbits were simultaneously placed on brain microdialysis and cardopulmonary bypass (CPB). Physiological parameters were regularly recorded. The extracellular samples were collected by microdialysis and measured. Brain damage was evaluated with histological methods. Results Higher doses of dopamine and sodium bicarbonate were administered in group H than in group L[(2. 07 ± 0. 63 ) mg vs (1.12±0.47) mg; (2.07 ±0.63) mg vs (1.12 ±0.47) mg,P<0.05]. The ratio of lactate/glucose and lactate/pyruvate in group H was increased significantly as compared with that in group L from the beginning of weaning from CPB[(12.63±0.44) vs (3.71 ±1.31); (13. 14±1.37) vs (3.82 ±1.41),P <0. 05]. In latter time of experiment, the glutamate values in group H remained at higher levels than in group L[(6. 02 ±0. 65) vs (2.21 ±0. 72) ,P <0. 05). The injured extent of neurons in group H was significantly severe than that in group L. Conclusion A low priming volume during DHCA could have a more significantly neuroprotective effect than a high priming volume.