A method for determining the haematocrit and / or blood volume and apparatus for the extracorporeal blood treatment with a device for determining the haematocrit and / or blood volume

摘要

It is a method and a device for determining the haematocrit hkt and / or blood volume as well as during extracorporeal blood treatment is described, the on a measurement of the pressure p in the extracorporeal blood circuit, in particular of the pressure p_type in the artiellen blood line upstream of the blood pump, is based. The respective relationship between haematocrit or blood volume and pressure, for different cannula diameters and different blood flow values stored bpr. For the respective cannula diameter and blood flow, the respective connection is selected and taking account of the selected relationship haematocrit and / or blood volume is determined. For the determination of the cannula diameter, which consists of a change in the blood flow is determined and change in pressure resulting from the pressure in the second webs the cannula. For this purpose, at different values of the blood flow the pressures measured and the pressure differential with predetermined value ranges representative of the individual cannula diameters compared.