title: Plasma viscosity, haematocrit and red-cell transport.
abstract: An erythrocyte transport function (ETF) is proposed, as an index of the efficiency of the circulation of red cells. Under defined conditions, this ETF is shown to be proportional to the ratio of haematocrit to whole-blood viscosity (phi/eta), a ratio already used by Chien. The variations of phi/eta with phi, at selected driving pressures in a capillary viscometer, are presented, both for normal and for pathological blood samples. Maximal values of phi/eta appear generally to occur at haematocrits of about 42%, and are strongly dependent upon plasma viscosity. They are also influenced by shear. The concept of 'isograds' (curves of phi/eta against phi at constant velocity gradient) is introduced, and is analysed in technical appendices which also deal with rates of shear in capillary and rotational viscometers when Newtonian or shear-sensitive liquids are measured.
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood; D001809:Blood Viscosity; D004912:Erythrocytes / Q000502:physiology*; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D009101:Multiple Myeloma / Q000097:blood; D010956:Plasmapheresis; D008258:Waldenstrom Macroglobulinemia / Q000097:blood