Microhemodynamics of capillary networks

Abstract

The single-file flow of red blood cells in microcirculatory networks is studied theoretically. A phase-separation rule for the cells at the bifurcations is established and the flow-pressure drop relationship for the individual flexible cells is obtained from the work of Sutera and co-workers [Capillary blood flow. II. Deformable model cells in tube flow. Microvasc. Res. 2, 420–433, 1970]. Differences between tube and discharge hematocrit resulting from the kinematics of the blood flow in the capillaries and plasma skimming occurring at the bifurcations are taken into account The model provides flows, pressure drops, hematocrit values and relative viscosities in all branches of the network. A purely fluid mechanical microhemoregulation is proposed. The mechanism of this peripheral blood regulation is the redistribution of red cells in the individual branches of the network corresponding to the morphology and the local flow rates, thus adjusting the hydraulic resistance to flow.