[Effect of hemodilution on systemic and capillary hematocrit].

In a cross-over study including 10 clinically healthy male volunteers, the hematocrit in the macro- and microcirculation was investigated prior to and 1 h, 3 h, 6 h and 24 h after iso- or (3 months later) hypervolemic hemodilution using 500 ml hydroxyethyl starch. The dilution effect observed after isovolemic hemodilution is more pronounced than after hypervolemic hemodilution. While isovolaemic hemodilution with 500 ml medium molecular weight hydroxyethyl starch leads to a reduction in the systemic hematocrit by 8.5% by volume, the capillary hematocrit at the time of the most marked dilution (1 h after hemodilution) decreases by only 1.3 hematocrit points in the cutaneous capillaries. After hypervolemic hemodilution, the systemic hematocrit decreases significantly by maximally 5.4% by volume, while the capillary hematocrit does not change significantly.