The effects of extreme hemodilutions on the autoregulation of cerebral blood flow, electroencephalogram and cerebral metabolic rate of oxygen in the dog.
The effects of extreme hemodilutions on the autoregulation of cerebral blood flow, electroencephalogram and cerebral metabolic rate of oxygen in the dog.
复制标题
极端血液稀释对狗脑血流自动调节、脑电图和脑氧代谢率的影响。
作者：
M. Maruyama;K. Shimoji;T. Ichikawa;M. Hashiba;E. Naito
在戊巴比妥钠麻醉的狗上，研究了血液深度稀释（Ht20%）和极度稀释（Ht5%）对平均动脉压（MAP）和脑血流量（CBF）关系的影响。在正常血压血液稀释（MAP 100 μ g）时，CBF与Ht值之间存在回归线：CBF（ml/100 g × min）=-98.9logHt（%）+195.5（p <0.001）。血液稀释使CBF增加，但其自动调节范围变窄，表明血液稀释时CBF对血压的敏感性逐渐增加。在CBF自动调节范围内，血液稀释对脑电图（EEG）没有显著影响，低于该范围时，EEG变慢。相反，即使在CBF自动调节范围内，血液稀释也会降低脑氧代谢率（CMRo 2），而MAP为100和40 mmHg之间的CMRo 2值无显著差异。因此，脑功能方面的脑电图似乎更相关的自动调节机制的CBF比CMRo 2值在血液稀释状态。
The effects of profound (hematocrit value, Ht 20%) and extreme (Ht 5%) hemodilutions on the relationship between the mean arterial pressure (MAP) and the cerebral blood flow (CBF) were studied in pentobarbital-anesthetized dogs. A regression line was found between the CBF and Ht values during normotensive hemodilution (MAP 100 torr): CBF (ml/100g X min) = -98.9 log Ht (%) + 195.5 (p less than 0.001). The CBF was increased by hemodilution, but the range of its autoregulation was narrowed, suggesting a progressive susceptibility of CBF to blood pressure with hemodilution. The electroencephalogram (EEG) was not significantly changed by hemodilution within the range of the CBF autoregulation, below which it became slowed. In contrast, the cerebral metabolic rate of oxygen (CMRo2) was decreased by hemodilution even within the range of the CBF autoregulation, while there were no significant differences in CMRo2 values between MAPs of 100 and 40 torr. Thus, the brain function in terms of the EEG seemed to correlate more with the autoregulatory mechanism of the CBF than with the CMRo2 value in the hemodiluted states.