STUDIES ON BLOOD VISCOSITY AT LOW SHEAR RATES
Annual progress rept. 1 Apr-31 Dec 1963
COLUMBIA UNIV NEW YORK COLL OF PHYSICIANS AND SURGEONS
Pagination or Media Count:
At low shear rates the logarithm of viscosity of heparinized and defibrinated blood obtained from man and dogs shows a linear relationship with the volume per cent of cells. Analyses of such semilog plots indicate that the dependence of plasma viscosity on shear rate can be attributed to the presence of fibrinogen and that the dependence of blood viscosity on volume per cent cells is unaltered by the removal of fibrinogen. Dextran preparations obtained from two different sources have similar effects on blood viscosity which increases in proportion to the molecular weight and the concentration of the dextran used. At a given shear rate and for a given cell percentage, the viscosity of heparinized blood obtained from five species of animals elephant, man, dog, sheep, goat shows a direct relationship to the mean corpuscular volume MCV. Such correlation between viscosity and MCV is less marked in Ringer-washed cell suspensions prepared from the blood of these species. Shrinkage of red cells by washing with a hypertonic solution results in an increase of mean corpuscular hemoglobin concentration MCHC and a rise of viscosity. Swelling of red cells by washing with a hypotonic solution causes a decrease of MCHC and a lowering of viscosity. In endotoxin shock, the outward filtration of plasma fluid across capillary walls is accelerated and the concentration of macromolecules in this fluid is also increased.
- Anatomy and Physiology