Effect of low molecular dextran on the microrheological properties of erythrocytes

The beneficial effect of low molecular dextran (Rheomacrodex) on the impaired micro-circulation was said to be the consequence of a decrease in the viscosity of blood due to hemodilution. In the present paper we report about the role of low molecular dextran on the flow properties of erythrocytes in-vitro. Blood samples of healthy volunteers were introduced in a standardized 8 mum-filter system and the flow rate through these filters was measured. Additional rheological measurements were performed simultaneously. In other blood samples different parts of the plasma were replaced by a iso-osmolar, iso-oncotic and iso-viscous Rheomacrodex solution. It was clear visible that the number of erythrocytes flowing through the 8 mum-filter within a given time had markedly increased when low molecular weight dextran was present in the suspension medium. Even when the equal parts of the natural plasma was replaced by undiluted 10% Rheomacrodex solution the filtration of erythrocytes had significantly increased, inspite of the higher viscosity of the whole blood compared to the blanks.- We are certain that this new microcirculatory effect is the consequence of an increased deformability of the red cells. The theoretical and clinical significance of these results have been discussed.