Objective: Using an isovolaemic model, the effect on the blood and plasma volumes of a newly developed medium-molecular weight (130 Kd) hydroxyethyl starch (HES) solution (degree of substitution 0.4) was investigated in 12 healthy male volunteers with the aid of 51Cr-radiolabelled erythrocytes.
Methods: Blood samples were drawn before and after 500ml bleeding as well as directly prior to the start of a 500ml HES infusion, and repeatedly up to 24 hours after treatment, for the measurement of haematocrit and gamma-counting, and the calculation of blood and plasma volumes.
Results: The blood and plasma volumes increased by a maximum of 0.385L (7%) and 0.620L (21%), respectively, at 30 minutes after the start of infusion, and returned to the baseline value at 24 hours after infusion. The plasma volume exceeded the volume prior to the start of bleeding by more than 5% for 19.15 hours. A clinically relevant expansion of the plasma volume persisted for at least 6 hours after the infusion and was comparable to the infused volume. The red blood cell volume remained stable after bleeding [mean: 2.01L; SD: 0.03L (range 1.95L to 2.05L)]. Local tolerability at the infusion site and systemic tolerability were good. Blood pressure, heart rate and ECG did not show clinically relevant deviations from normal.
Conclusion: It is concluded that a blood withdrawal of 500ml can be replaced isovolaemically by 500ml of the new 6% HES (130/0.4) solution.