Flow behavior of neonatal and adult erythrocytes in narrow capillaries

Abstract This study was designed to analyze the flow behavior of red blood cells (RBCs) in circular vessels with diameters of 3 to 6 μm by means of a mathematical model. According to this model, the RBC flow velocity is 1 mm/sec, RBCs assume axisymmetric shape, and the gap between the RBC and the vessel wall allows sufficient lubrication. The flow resistance depends on the surface area and volume of RBCs, the plasma viscosity, and the vessel diameter. Surface area and volume of RBCs from 10 term neonates and 10 adults were determined by means of a micropipet system and plasma viscosity was measured using a capillary viscometer. Neonatal RBCs had larger volumes (107 ± 6 fl vs 90 ± 4 fl) and surface areas (154 ± 7 μm 2 vs 137 ± 7 μm 2 ) than adult RBCs ( P P