THE EFFICACY OF RETROGRADE CEREBRAL PERFUSION

近年来，深低温逆行脑灌注在胸主动脉手术中得到广泛应用。然而，这些方法的有效性仍存在争议。在此基础上，我们通过实验评估了逆行脑灌注（RCP）在循环骤停期间的疗效。然后用狗在常温状态下评估RCP的疗效。采用近红外分光光度法（NIRS）根据个体差异（灌注流量、灌注压力、静脉是否存在瓣膜等）测定脑代谢和氧合。用直接刺激脊髓引起的脑诱发电位估计脑功能。在正常状态下，将狗分为两组。第一组（n=5）；单纯循环停止15 min，再灌注60 min， II组（n=S）；循环停搏15分钟，再灌注60分钟。结果如下：1)在RCP中，NIRS主要通过静脉瓣来检测脑灌注不良。2)在嘈杂环境下，直接刺激脊髓诱发的脑诱发电位（体感皮层诱发电位）比刺激周围神经诱发的脑诱发电位更有效。3)在近红外光谱控制脑灌注的情况下，分析pi组和pii组的诱发电位、潜伏期、消失时间和恢复时间。从本研究中，我们得出结论，循环停止时逆行脑灌注的效果不足以维持正常状态。那么RCP可能只有在深度低温循环停止时才有可能通过周围的静脉有效地冷却大脑。

Deep hyporthermic retrograde cerebral perfusion has been employed recently during operation on thoracic aorta. However the efficacy of of the methods are still controversial. Then we estimated the efficacy of retrograde cerebral perfusion (RCP) during circulatory arrest experimentally. Then dogs were used for estimating the efficacy of RCP in normothermic state. Near-infrared spectrophotometory (NIRS) was employed for measurement of cerebral metabolism and oxygenation according to the individual differences (perfusion flow, perfusion pressure, existence of valve in vein, etc.). And evoked cerebral potentials elicited by direct stimulation of the cord was employed for estimating cerebral function. In normothermic state, the dogs were divided into two groups. Group I (n=5) ; simple ciculatory arrest 15 min, reperfusion 60 min, Group II (n=S) ; RCP during ciculatory arrest 15 min, reperfusion 60 min. Results were as follows ; 1) NIRS was useful during RCP for detecting malperfusion of the brain mainly by valve of veins. 2) Evoked cerebral potentials elicited by direct stimulation of the cord was useful in the noisy circumstances compared with them by stimulation of the peripheral nerve (somatosensory cortical evoked potentials). 3) Under controlling cerebral perfusion by NIRS,potentials, latencies, time of their loss and recovering time of evoked potentials were analyzed in groupI and groupII.From this study, we concluded that the efficacy of retrograde cerebral perfusion during circulatory arrest is not enough for maintaining normothermic state. Then RCP might have possibility of cooling brain effectively through veins around it only during deep hypothermic circulatory arrest.