Rheological consequences of osmotic red cell crenation.

Abstract

The rise in blood viscosity at very low shear rates is based upon the formation of a three dimensional cell structure build-up by red cell rouleaux. Osmotic red cell crenation abolishes rouleaux formation and the secondary formation of larger red cell aggregates. Consequently, in suspensions of crenated red cells in plasma the viscosity at low shear rates is reduced. On the other side, however, the viscosity at high shear rates is increased. The latter phenomenon is caused by a reduced viscous deformability of osmotically shrunken red cells, as is shown by a marked increase in packed cell viscosity (99% hematocrit). These results suggest that the anomalous viscosity of blood is determined by at least two factors, red cell aggregation and red cell deformation.