[Hemodilution, hemorheology and oxygen supply]

There is no doubt that hemorheological hemodilution in patients with ischaemic diseases improves the tissue oxygen supply, provided certain preconditions for therapy modalities are granted. As can be concluded from the title of this summary it is basically possible, not only to improve the blood flow properties but also - what is even more important - to optimize the oxygen supply of ischaemic tissue through hemodilution therapy. In the case of chronical arterial occlusive disease of the legs it was for the first time possible to establish a haematocrit value of about 40% as a guideline for the decrease of haematocrit in the course of hemodilution. This value, however, cannot be applied to other hemodilution schemes, other plasma substitutes, other states of chronical arterial occlusive disease or even other organs without specific examination. Before further comprehensive studies are initiated for instance of hemorheological hemodilution therapy in patients with cerebral ischaemia, optimal conditions should be experimentally determined in order to improve the prospects of the studies - as was proved in the case of intermittent claudication. Drawing from 25 years of clinical and scientific experience with hemodilution I would like to emphasize that today its therapeutic mechanism has been investigated to a high degree and its effectiveness in patients with peripheral ischaemic diseases as well as retinal ischaemic diseases can be considered as largely guaranteed. Contradictory results of clinical studies of cerebral ischaemia demand new clinical studies which not only should be improved as regards their design but also should contain concrete guidelines on the modalities of hemodilution therapy including the "optimal" haematocrit values which are to be reached.