Duling B R, Sarelius I H, Jackson W F
Int J Microcirc Clin Exp. 1982;1(4):409-24.
Relations between bulk flow into skeletal muscles and microscopically observed capillary flow are compared and disagreements between the two types of data are found. Mean capillary blood velocity was computed using data from a variety of literature sources and assuming uniform distribution of flow through a parallel array of capillaries. The average ratio of measured red cell velocity to computed mean blood velocity was 4.4 +/- 1.0. This is statistically different from the measured value reported in the literature of 1.3. In the cremaster muscle, bulk flow of red cells into the tissue was not statistically different from the measured flux of single red cells through capillaries observed microscopically. The factors which contribute to this apparent agreement of mass balance are not understood, however. Capillary hematocrit is very low and the low capillary hematocrit has been explained by others by the presence of nonuniform flow distribution among the capillaries (shunts or flow heterogeneity). However, for the cremaster data sample, red cells were accounted for in observed capillary flow and red cells were distributed rather homogeneously through the capillaries. This suggests that low capillary hematocrit is the result neither of shunting of red cells around the capillaries nor of nonuniform capillary red cell flow alone. There does not appear to be any well-accepted phenomenon which will explain the findings of: 1) low apparent mean blood velocity; 2) low and variable hematocrit; and 3) apparent conservation of red cell mass. The findings can be reconciled, however, if the capillary rheology is more complex than heretofore anticipated, with a stabilized layer of plasma on the inner surface of the capillary in the order of a 1-micrometer thickness. While there is little direct evidence for such a layer at this time, data which are consistent with the possible existence of such a layer are presented.
对进入骨骼肌的总体血流量与显微镜下观察到的毛细血管血流量之间的关系进行了比较，发现这两类数据之间存在差异。利用来自各种文献来源的数据，并假设血流通过平行排列的毛细血管呈均匀分布，计算了平均毛细血管血流速度。测得的红细胞速度与计算出的平均血流速度的平均比值为4.4±1.0。这在统计学上与文献报道的1.3的测量值不同。在提睾肌中，红细胞进入组织的总体血流量与显微镜下观察到的单个红细胞通过毛细血管的通量在统计学上没有差异。然而，导致这种明显的质量平衡一致性的因素尚不清楚。毛细血管血细胞比容非常低，其他人用毛细血管间血流分布不均匀（分流或血流异质性）来解释低毛细血管血细胞比容。然而，对于提睾肌的数据样本，在观察到的毛细血管血流中考虑了红细胞，并且红细胞在毛细血管中分布相当均匀。这表明低毛细血管血细胞比容既不是红细胞在毛细血管周围分流的结果，也不是仅由毛细血管红细胞血流不均匀导致的。似乎没有任何被广泛接受的现象能够解释以下发现：1）明显较低的平均血流速度；2）低且可变的血细胞比容；3）明显的红细胞质量守恒。然而，如果毛细血管流变学比迄今为止预期的更复杂，即毛细血管内表面有一层厚度约为1微米的稳定血浆层，那么这些发现是可以调和的。虽然目前几乎没有直接证据证明存在这样一层，但本文提供了与这种层可能存在相一致的数据。
