Whole-blood viscosity, as determined by plasma viscosity, haematocrit, and shear.
The viscometers used were: (a) a proprietary rotational coaxial-cylinder instrument; and (b) a Harkness capillary-tube viscometer. In (a), the mean shear-rate is selected by the choice of rotational speed. In (b), the wall shear-stress is selected by the choice of driving-pressure. If the viscosity is varied, the mean shear-rate varies, at constant wall shear-stress. The present paper attempts to show how, in principle, a complete family of "constant-rate" (rotational) curves can be computer-plotted from two suitably-spaced capillary-tube measurements. The reverse process, involving the correction of "playback" errors, is touched upon. A variable "Einstein coefficient" is derived from the principal parameters in the computer solution; and the basic problems of compatibility in "rates of shear" are discussed.
D001809:Blood Viscosity; D006400:Hematocrit; D006801:Humans; D010949:Plasma / Q000502:physiology; D013314:Stress, Mechanical