Hypervolemic haemodilution and completed stroke: how important is the application time for its effect?

Abstract

In 75 patients with completed stroke hypervolemic haemodilution was performed for 1 day with 500 ml 6% HES 200.000/0.6-0.66 (Elohäst) to test the acute influence of application time for haemorheological changes. The patients were divided into 3 groups randomly selected: group A received the infusion for 2 hours, group B for 4 hours and group C for 6 hours. Haematocrit (HCT), whole blood viscosity (VI-VB), blood elasticity (EL-VB) and plasma viscosity (VI-PL) were determined before onset of infusion, after 6 and 18 hours subsequently. The values obtained were compared with the onset results. In all groups and parameters after 6 hours there was a significant decrease. After 18 hours group A showed a significant higher value of HCT and increasing trends for VI-VB and EL-VB. In group B after 18 hours a significant decrease of VI-VB could be observed. In group C all values remained significantly below the onset. The results show, that one important haemorheological argument for an effective form of haemodilution should also be a long application time. This might be one of the reasons, why in some studies with hypervolemic haemodilution no positive results could be obtained.