[The study on cerebral hemodynamics during selective cerebral perfusion]

This study was undertaken to clarify characterization on cerebral hemodynamics during deep hypothermic selective perfusion (SCP) in 18 pigs. Besides, the changes on cerebral hemodynamics were investigated with obstruction to venous drainage due to the clamp of superior vena cava (SVC) cannula. For SCP, blood was infused into aortic arch with the clamp of descending aorta, during 90 minutes at 20 degrees C. We measured regional cerebral blood flow (CBF), intracranial pressure (ICP), and carotid arterial flow (CAF), and carotid arterial pressure. The carotid arterial pressure as perfusion pressure was not significantly correlated with CAF, CBF and ICP. Although CAF increased as pump flow rate increased, the relationship between pump flow and CBF was not significant. Moreover, SVC pressure showed a tendency to increase, as CAF increased. Both ICP and internal jugular vein pressure (IJVP) were significantly (p < 0.01) increase, and CAF was significantly (p < 0.05) decrease with the clamp of SVC cannula. On the other hand, both ICP and IJVP were significantly decrease, and both CAF and CBF were increase, without unclamp of SVC cannula. The results suggest that cerebral autoregulation is intact during deep hypothermic SCP, and hyperperfusion cause the increase of shunt flow in extracranial area, and besides, the increase of ICP with obstruction to venous drainage cause decrease in cerebral blood flow.