人工微血管网络中输注血细胞比容和灌注压对血细胞比容降低（法赫瑞厄斯效应）的影响。
Influence of feeding hematocrit and perfusion pressure on hematocrit reduction (Fåhraeus effect) in an artificial microvascular network.
作者信息
Reinhart Walter H, Piety Nathaniel Z, Shevkoplyas Sergey S
机构信息
Kantonsspital Graubünden, Chur, Switzerland.
Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX, USA.
出版信息
Microcirculation. 2017 Nov;24(8). doi: 10.1111/micc.12396.
OBJECTIVE
Hct in narrow vessels is reduced due to concentration of fast-flowing RBCs in the center, and of slower flowing plasma along the wall of the vessel, which in combination with plasma skimming at bifurcations leads to the striking heterogeneity of local Hct in branching capillary networks known as the network Fåhraeus effect. We analyzed the influence of feeding Hct and perfusion pressure on the Fåhraeus effect in an AMVN.
METHODS
RBC suspensions in plasma with Hcts between 20% and 70% were perfused at pressures of 5-60 cm H O through the AMVN. A microscope and high-speed camera were used to measure RBC velocity and Hct in microchannels of height of 5 μm and widths of 5-19 μm.
RESULTS
Channel Hcts were reduced compared with Hct in 5 and 7 μm microchannels, but not in larger microchannels. The magnitude of Hct reduction increased with decreasing Hct and decreasing ΔP (flow velocity), showing an about sevenfold higher effect for 40% Hct and low pressure/flow velocity than for 60% Hct and high pressure/flow velocity.
CONCLUSIONS
The magnitude of the network Fåhraeus effect in an AMVN is inversely related to Hct and ΔP.
目的
在狭窄血管中，由于快速流动的红细胞集中在血管中心，而流动较慢的血浆沿血管壁分布，再加上在分支处的血浆撇除现象，导致分支毛细血管网络中局部血细胞比容出现显著异质性，即所谓的网络法赫效应。我们分析了输入血细胞比容和灌注压对人工微血管网络中法赫效应的影响。
方法
将血细胞比容在20%至70%之间的红细胞悬液以5至60厘米水柱的压力灌注通过人工微血管网络。使用显微镜和高速摄像机测量高度为5微米、宽度为5至19微米的微通道中的红细胞速度和血细胞比容。
结果
与5微米和7微米微通道中的血细胞比容相比，通道血细胞比容降低，但在较大的微通道中未降低。血细胞比容降低的幅度随着血细胞比容的降低和ΔP（流速）的降低而增加，与60%血细胞比容和高压/流速相比，40%血细胞比容和低压/流速时的效应高出约7倍。
结论
人工微血管网络中网络法赫效应的幅度与血细胞比容和ΔP呈负相关。
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