Sarelius I H
Department of Biophysics, University of Rochester, New York 14642.
Microvasc Res. 1990 Jul;40(1):88-98. doi: 10.1016/0026-2862(90)90010-o.
Heterogeneity of blood flow distribution was measured in capillary networks in cremaster muscles of anesthetized Golden hamsters (nembutal, 70 mg/kg, ip). The relative dispersion of Q/PS, where Q is blood flow, P is permeability, and S is exchange surface area, was estimated; in microvascular terms (and assuming uniform permeability) this ratio reduces to vr/l, where v is plasma velocity, r is vessel radius, and l is vessel length, and where v/l = 1/T, where T is transit time. Distributions of 1/T across complete capillary networks significantly increased in relative dispersion from 68.2 to 97.8% during hyperemia, suggesting an increase in flow heterogeneity with increased inflow. In contrast, relative dispersion of 1/T did not change significantly from rest (72.0%) to hyperemia (66.1%) in capillary segments sampled randomly across the tissue. Other microvascular indices of flow (velocity, cell content) did not reflect the changes in relative flow dispersion shown by the changes in 1/T. The analysis demonstrates that estimates of flow heterogeneity are sensitive both to the selection of an appropriate flow variable and to the manner in which this variable is sampled in the capillary bed.
在麻醉的金黄地鼠（戊巴比妥，70毫克/千克，腹腔注射）提睾肌的毛细血管网络中测量血流分布的异质性。估计了Q/PS的相对离散度，其中Q是血流量，P是渗透率，S是交换表面积；从微血管角度来看（并假设渗透率均匀），该比率简化为vr/l，其中v是血浆流速，r是血管半径，l是血管长度，且v/l = 1/T，其中T是通过时间。在充血期间，整个毛细血管网络中1/T的分布相对离散度从68.2%显著增加到97.8%，表明随着流入量增加，血流异质性增加。相比之下，在整个组织中随机采样的毛细血管段中，1/T的相对离散度从静息时的72.0%到充血时的66.1%没有显著变化。其他血流微血管指标（流速、细胞含量）没有反映出1/T变化所显示的相对血流离散度的变化。分析表明，血流异质性的估计对合适的血流变量的选择以及该变量在毛细血管床中的采样方式都很敏感。
