The relative influence of hematocrit and red blood cell velocity on oxygen transport from capillaries to tissue.
The relative influence of hematocrit and red blood cell velocity on oxygen transport from capillaries to tissue.
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DOI：
10.1111/micc.12337
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发表时间：
2017-04
期刊：
影响因子：
--
通讯作者：
Jenny P
中科院分区：
文献类型：
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作者：
Lücker A;Secomb TW;Weber B;Jenny P
氧向实质细胞的转运主要发生在微血管水平，并依赖于对流红细胞(RBC)通量，RBC通量与毛细血管内红细胞压积和红细胞速度的乘积成正比。本研究探讨这两种因素对组织氧分压的相对影响。一个简单的分析模型被用来量化红细胞压积、红细胞速度和血流对毛细血管周围组织氧合的影响。预测的组织PO2水平与详细的计算模型进行了比较。红细胞压积对组织氧分压的影响比红细胞速度大。RBC速度的影响随着与小动脉的距离增加而增大。分析结果与数值计算结果吻合较好，并对差异进行了解释。当红细胞压积较低时，传质系数与红细胞速度有显著的相关性。对于毛细血管中给定的RBC流量，周围组织中的PO2随着红细胞压积的增加而增加，这是由于血管内对从RBC到组织的扩散氧运输的阻力降低的结果。这些结果有助于理解血流变化对氧气运输的影响，例如发生在大脑中的功能性充血。
Oxygen transport to parenchymal cells occurs mainly at the microvascular level, and depends on convective red blood cell (RBC) flux, which is proportional in an individual capillary to the product of capillary hematocrit and red blood cell velocity. This study investigates the relative influence of these two factors on tissue oxygen partial pressure (Po2). A simple analytical model is used to quantify the respective influences of hematocrit, RBC velocity and flow on tissue oxygenation around capillaries. Predicted tissue Po2 levels are compared with a detailed computational model. Hematocrit is shown to have a larger influence on tissue Po2 than RBC velocity. The effect of RBC velocity increases with distance from the arterioles. Good agreement between analytical and numerical results is obtained and the discrepancies are explained. Significant dependence of mass transfer coefficients on RBC velocity at low hematocrit is demonstrated. For a given RBC flux in a capillary, the Po2 in the surrounding tissue increases with increasing hematocrit, as a consequence of decreasing intravascular resistance to diffusive oxygen transport from RBCs to tissue. These results contribute to understanding the effects of blood flow changes on oxygen transport, such as occur in functional hyperemia in the brain.