Comparison of the effects of infusion with hydroxyethyl starch and low molecular weight dextran on cerebral blood flow and hemorheology in normal baboons.

Cerebral blood flow (CBF) and hemorheological parameters, such as hematocrit, plasma viscosity, and erythrocyte aggregation, were measured before and up to 7 h after 60-min infusions with 10% hydroxyethyl starch (HES), or 0.9% NaCl solution and 10% low molecular weight dextran (LMWD) in a total of 12 normal baboons. Infusion of HES increased CBF up to 48% from the resting level, and decreased hematocrit without an increase in plasma viscosity. Infusion of LMWD decreased hematocrit with an increase in CBF of up to 9.6%, but increased plasma viscosity at the same time. The disaggregating effect for erythrocytes was rather more obvious with LMWD than with HES but without significant difference between them. These data show different rheological effects with infusions of HES and LMWD on the physiological conditions of normal baboons.