Kee D B, Wood J H
Cerebral Blood Flow Laboratory, Emory University School of Medicine, Atlanta, Georgia.
Neurol Res. 1991 Dec;13(4):205-8. doi: 10.1080/01616412.1991.11739993.
The effect of haemodilution without volume expansion (isovolemic haemodilution) was assessed with respect to blood flow and oxygen transport across stenotic lesions of progressive severity in the dog carotid artery. As the mean haematocrit (Hct) was reduced from 40 +/- 1% (+/- SEM) to 32 +/- 0% (p less than 0.001), reductions in vascular resistance were significant across the 90% (p less than 0.001) and 95% (p less than 0.0003) relative carotid stenoses. Isovolemic haemodilution reduced fresh blood viscosity significantly by 27 +/- 3% (p less than 0.001) and 42 +/- 4% (p less than 0.001) at the low shear rates of 10 sec-1 and 1 sec-1 which are typical of low-flow states. Following a 20% reduction in Hct 30 to 35% increase (p less 0.001) in carotid blood flow occurred at non-critical degrees of stenosis while a mean 83% increase (p less than 0.001) occurred at the highly critical 95% relative stenosis. Oxygen transport after a 22% decrease in blood haemoglobin was significantly increased by 28% (p less than 0.01) at the 95% relative stenosis level. These data provide a physiologic rationale for the beneficial effects of haemodilution in acute cerebral ischaemia, cerebral vasospasm and cerebral revascularization or carotid endarterectomy.
在犬颈动脉中，针对血流以及跨越不同严重程度进行性狭窄病变的氧输送情况，评估了无容量扩张的血液稀释（等容血液稀释）的效果。随着平均血细胞比容（Hct）从40±1%（±标准误）降至32±0%（p<0.001），在相对颈动脉狭窄90%（p<0.001）和95%（p<0.0003）时，血管阻力的降低具有显著性。等容血液稀释在10秒⁻¹和1秒⁻¹的低剪切率（这是低血流状态的典型特征）下，显著降低了新鲜血液黏度，分别降低了27±3%（p<0.001）和42±4%（p<0.001）。在非临界狭窄程度下，Hct降低20%后，颈动脉血流量增加了30%至35%（p<0.001），而在高度临界的95%相对狭窄时，平均增加了83%（p<0.001）。在相对狭窄95%水平，血红蛋白降低22%后，氧输送显著增加了28%（p<0.01）。这些数据为血液稀释在急性脑缺血、脑血管痉挛以及脑血运重建或颈动脉内膜切除术中的有益作用提供了生理学依据。
