HEPARIN EFFECT ON RED-BLOOD-CELL AGGREGATION

We studied the effect of relatively high dosages of heparin (25-150 U/ ml) on some rheological parameters of donor blood. It was found that h eparin increased the erythrocyte sedimentation rate (ESR) and low shea r blood viscosity at all concentrations studied. The increase of these parameters indicates an elevation in RBC aggregation. In all samples with a heparin concentration of 100 U/ml, the average ESR was increase d by approximately 75% (p < 0.001); whole blood viscosity increased un der shear rate, gamma = 0.277 sec-1, by approximately 30% (p < 0.001). Since bolus injection of heparin may result in transient high local c oncentration, these results suggest a possible additional adverse effe ct to the well known heparin effect on platelet aggregation.