OPTIMAL PERFUSION CONDITION FOR RETROGRADE BRAIN PERFUSION

实验1。经矢状窦和SVC逆行灌注。激光血流仪测脑表面血流量分别为5.5、9.0、10.1ml/100g/min，驱动压力分别为15、25、35mmHg。在15、25、35mmHg驱动压力下，逆行灌注90分钟后，中性红生命染色测得脑组织pHi值分别为6.38 ~ 6.8、6.73 ~ 7.08、6.79 ~ 7.16。大脑前部/皮质微球测组织血流量分别为2.2/4.0、7.0/12.1和8.1/13.6ml/100g/min。脑逆行灌注功能驱动压在25mmHg及以上，对脑有保护作用。虽然在该动物模型中证实脑组织有大量血流量，但血流和局部pHi呈高额状。在实验上建立均匀脑灌注来检测逆行灌注后的脑水肿。实验2。在20c下进行极低血流顺行灌注（120min），观察灌注压、脑组织血流量与脑组织pHi的关系。10、20ml/kg/min灌注脑组织pHi可使脑组织pHi维持高120分钟。当驱动压在10mmHg以上时，大脑皮层血流量大于10.2<正负>1.9ml/100g/min。当皮层血流量大于9ml/100g/min时，大脑皮层pHi值大于7.1。当皮层血流量小于此值时，脑耗氧量和皮层pHi降低，而葡萄糖摄取并未同时降低。这种血流小于10ml/100g/min的灌注状态会引起脑酸中毒，可能造成脑损伤。应该进一步研究这种不完全的脑灌注是否保护了大脑，或者相反地损害了大脑

Experiment 1.Dogs were perfused retrogradely via the sagittal sinus and SVC.Cerebral surface blood flow by laser flowmetry was 5.5,9.0,10.1ml/100g/min with driving pressure of 15,25,35mmHg.Cerebral tissue pHi measured photometrically with Neutral Red vital staining was 6.38-6.8,6.73-7.08,6.79-7.16 after 90 minutes of retrograde perfusion with driving pressure of 15,25 and 35mmHg. Tissue blood flow measured with microspheres in the anterior cerebrum/cortex was 2.2/4.0,7.0/12.1 and 8.1/13.6ml/100g/min, respectively. Retrograde brain perfusion with functional driving pressure of 25mmHg or more protects the brain. Although substancial blood flow in the brain tissue was proved in this animal model, there was a hyperfrontality in blood flow and regional pHi. Homogenous brain perfusion should be experimentally established to examine brain edema after retrograde perfusion.Experiment 2.Antegrade very low-flow perfusion (120 minutes) was tested at 20ﾟC to examine the relationship between perfusion pressure, brain tissue blood flow and brain tissue pHi. Brain tissue pHi was maintained high for 120 minutes by the perfusion with flow-rate of 10 and 20ml/kg/min. Cerebral cortex blood flow was larger than 10.2<plus-minus>1.9ml/100g/min when the driving pressure was above 10mmHg. Cerebral cortex pHi was greater than 7.1 when cortex blood flow was greater than 9ml/100g/min. When the cortex blood flow was smaller than this, brain oxygen consumption and cortex pHi decreased while glucose uptake did not simultaneously decrease. This perfusion condition with blood flow less than 10ml/100g/min causes brain acidosis and may cause brain damage. It should be further investigated whether this incomplete brain perfusion protects the brain or not, or paradoxically insults the brai