The changes of low-shear-rate hemorheological properties depending on the fluid used for transfusion.

We investigated the influence of kind of fluids used for transfusion - crystalloids and colloids - on the rheological parameters of blood with a special focus on the range of low shear rates. The blood viscosity measurements were performed with the use of a rotary-oscillatory rheometer Contraves LS 40. The investigation includes the measurements of blood viscosity and a hematocrit value at three stages: before, just after and two hours after transfusion. On the basis of results obtained for a group of patients prepared for procedures in epidural anaesthesia we concluded that the dilution effect for colloids (HES and dextran) was maintained longer then for crystalloids (Ringer solution). Measurements of blood viscosity at the shear rate of 1 s(-1) showed that this viscosity had the smallest value in the group of patients with HES 200/0.5 as a transfusion fluid (p<0.001).