A numerical study of plasma skimming in small vascular bifurcations.
Owing in part to a plasma-skimming mechanism, the distribution of red blood cells (RBCs) into branches of microvascular bifurcations typically differs from the distribution of the bulk blood flow. This paper analyzes the plasma-skimming mechanism that causes phase separation due to uneven distribution of red blood cells at the inlet cross section of the parent vessel. In a previous study, the shape of the surface that divides the flow into the branches was found by numerical simulation of three-dimensional flow of a homogeneous Newtonian fluid in T-type bifurcations. Those findings are used in this study to determine, as a first approximation, the side-to-parent vessel RBC flux ratio and discharge hematocrit ratio as a function of corresponding flow ratios. Calculations are based on the assumption that RBCs move along streamlines of a homogeneous Newtonian fluid and are uniformly distributed within a concentric core at the inlet cross section of the parent vessel. The results of our calculations agree well for a wide range of flow parameters with experimental data from in vivo and in vitro studies.
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Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205.
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D001783:Blood Flow Velocity; D004912:Erythrocytes / Q000502:physiology*; D005069:Evaluation Studies as Topic; D006400:Hematocrit; D006439:Hemodynamics; D016015:Logistic Models; D008433:Mathematics; D008833:Microcirculation; D008955:Models, Cardiovascular; D010949:Plasma / Q000502:physiology*; D012212:Rheology