Erythrocyte destruction under periodically fluctuating shear rate: comparative study with constant shear rate

The hydrodynamic effect of periodically fluctuating shear rate on erythrocyte destruction was quantitatively studied in vitro in comparison with constant shear rates. Uniform shear rates (less than 1,000 s-1; constant or sinusoidally fluctuating with time) were applied to heparinized canine blood contained in the concavo-convex type of Couette flow testing machine for (1.8-9.0) x 10(3) s at 24 degrees C. The results show that the erythrocyte destruction (evaluated with hemolysis ratio; plasma hemoglobin count per whole blood hemoglobin count) decreases when the exposure time of larger (greater than 500 s-1) shear rates is interspersed with smaller (less than 300 s-1) shear rates.