Abstract
As the temperature dependence of relative apparent whole blood viscosity η rel is still controversial, the relation between the temperature dependence of red cell aggregation (RCA) and that of η rel was examined in normal donors and in patients with venous ulcers of the leg. Apparent whole blood viscosity was measured in the DEER-rheometer (0.01Pa < τ < 2.9Pa) at 10°C, 20°C, 30°C and 37°C. The instrument was calibrated for each temperature to correct for changes in viscometer geometry. Simultaneously the minimal shear stress τ Tmin to keep RCA dispersed was determined by photometric aggregometry. η rel was found to increase with decreasing temperature. By basing the relative cold induced increase in η rel on the state of RCA as defined by the ratio of τ/τ Tmin the relation between both features is verified: With increaslng RCA the cold induced increase in η rel is progressively enhanced.
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