Osmolality- and hematocrit- mediated flow behavior of RBC suspensions in 33 μm ID tubes

Article type: Research Article

Authors: McKay, Colin B.^{; *} | Meiselman, Herbert J.

Affiliations: Department of Physiology and Biophysics, University of Southern California School of Medicine, 2025 Zonal A venue, Los Angeles, California 90033, USA

Note: [*] Present address: Biomedical Engineering Laboratory, Rice University, P.O.Box 1892, Houston, TX 77251, USA.

Note: [] Accepted by: Editor G.W. Schmid-Schönbein

Abstract: The effects of suspending medium osmolality (166 to 736 mosm/kg) on relative viscosity (ηr) and tube hematocrit (HT) measured in 33 diameter tubes were studied for 40, 47 and 57% feed hematocrit (HFk) suspensions of human RBC in buffer. At all feed hematocrits, ηr increased sharply for the hypertonic media, but was essentially insensitive to hypotonicity. HT/HF was less affected by osmolality (13% change over the entire range of osmolality and feed hematocrit). Viscosities could not be calculated from the experimental HT values. However, ηr could be predicted from RBC number concentration and the tube diameter/RBC volume ratio via a semi-empirical model. RBC transport efficiency depended on both feed hematocrit and osmolality, and was maximal at or near isotonic conditions. Our results appear applicable to non-isotonic regions of the microcirculation, and to estimation of flow resistance for RBC with abnormal cellular mechanical properties.

Keywords: Viscosity, Tube Hematocrit, Fåhraeus-Lindqvist effect, Fåhraeus effect, RBC Transport

DOI: 10.3233/BIR-1989-26416

Journal: Biorheology, vol. 26, no. 4, pp. 863-874, 1989