Blood viscosity and optimal hematocrit in narrow tubes

Article type: Research Article

Authors: Stadler, Achim A. | Zilow, Eugen P. | Linderkamp, Otwin

Affiliations: Division of Neonatology, Department of Pediatrics, University of Heidelberg, D-6900 Heidelberg, Federal Republic of Germany

Note: [] Accepted by: Editor P. Gaehtgens

Abstract: Blood viscosity in normal adults was measured in glass tubes with diameters of 50, 100 and 500 μm for a wide range of adjusted feed hematocrits (15-70%). Blood viscosity decreased at each of the adjusted feed hematocrits when going from a 500-μm tube to a 50-μm tube. The viscosity reduction increased with increasing hematocrit. The steepness in the hematocrit-viscosity curves decreased with decreasing tube diameter. Erythrocyte transport efficiency (hematocrit / blood viscosity) was calculated to estimate the optimal hematocrit for oxygen transport. Optimal hematocrit averaged 38% in 500-μm tubes, 44% in 100-μm tubes and 51% in 50-μm tubes. Our results suggest that the strong Fåhraeus-Lindqvist effect at high hematocrits may help to maintain oxygen transport in polycythemic patients as long as the driving pressure is sufficient.

Keywords: Blood viscosity, hematocrit, oxygen transport, red blood cell (RBC)

DOI: 10.3233/BIR-1990-27513

Journal: Biorheology, vol. 27, no. 5, pp. 779-788, 1990