HEMORHEOLOGICAL CHANGES IN PREOPERATIVE H EMODILUTION DURING TOTAL HIP-REPLACEMENT - RANDOMIZED STUDY WITH A HYDROXYETHYLSTARCH 200,000 0.62 (HES) VERSUS A DEXTRAN 60,000/

Hemodilution can be used to save blood transfusion during total hip re placement. We have carried out a randomized study to compare the hemor heological effects of two plasma substitutes : a hydroxyethylstarch 20 0,000/0.62 versus a dextran 60,000. Twenty-two patients were hemodilut ed with 20 mk/kg of either substitute, just after the spinal anesthesi a. Whereas the hematocrit have fallen by 30 % in the two groups, signi ficant differences are observed about hemorheological parameters. The plasma viscosity express a greater increase at hour 4 in the dextran g roup. The whole blood viscosities are more increased in the dextran gr oup at hour 4 and 24. The erythrocyte aggregation is decreased in the HES group at hour 4 and 24, but is increased in the dextran group. The fibrinogen is more increased in the dextran group at day 7. In spite of similar hemodilutions, the two substitutes express different hemorh eological effects with a favourable role of HES on erythrocyte agregat ion and blood viscosities. This can improve the microcirculation and d ecrease the activation of the endothelial cells, reducing the inflamma tory reaction.