THE DETERMINATION OF BLOOD VISCOSITY IN MAN BY A METHOD BASED ON POISEUILLE'S LAW

Abstract

A method for the detn. of absolute blood viscosity in vessels 0.3 mm. diam. or larger is described. This technic involves venepuncture, a detn. of venous pressure, and the measurement of flow rate of blood through a needle calibrated as to length and diam. The avg. intrasubject standard deviation utilizing this method was found to be 0.12 with a coeff. of variation of 4.5%. In 72 patients the hematocrit was correlated with the absolute viscosity and found to follow closely the slope of a curve derived from Hatschek''s formula, [image]Patients with hematocrits from 14 to 76% were studied and were found to have absolute viscosity levels of 1.32 to 7.80 centipoises. At hematocrits of 40% to 45%, blood viscosity ranged from 2.30 to 2.75 centipoises. The use of Hatschek''s formula and the hematocrit to predict absolute blood viscosity is only possible in the presence of normal plasma constituents and erythrocytes of normal size and shape.