Fan F C, Chen R Y, Schuessler G B, Chien S
Am J Physiol. 1980 Apr;238(4):H545-22. doi: 10.1152/ajpheart.1980.238.4.H545.
The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.
在20只戊巴比妥麻醉的犬中研究了局部血流动力学改变和氧运输速率对血细胞比容（Hct）的反应。12只犬通过与血浆进行等容交换实现血液稀释，8只犬通过输注浓缩红细胞实现血液浓缩。采用微球技术测定心输出量和局部血流量。血液稀释时，心肌和脑血流量的增加与心输出量的增加不成比例；心肌的氧供应保持不变，而脑的氧供应仅略有下降。血液浓缩时，心肌和脑发生血管舒张以维持恒定的氧供应。无论Hct向哪个方向改变，脾血管均有明显的血管收缩。肝、肠和肾血管的反应为轻度血管收缩，并在Hct为30%至55%之间维持恒定的氧供应。因此，在Hct改变期间，血流重新分布至心肌和脑。不同器官维持恒定氧供应的最佳Hct范围不同。
