Device for the extracorporeal treatment of blood, and method of controlling it

The invention relates to haemodialysis and haemofiltration therapy and is predominantly intended for the treatment of chronic kidney failure. It is the aim of the invention to permit free alternation between the treatment methods of haemodialysis, haemofiltration and sequential ultrafiltration and hence, in particular, to provide an optimum individual therapeutic regimen. The object of the invention is a uniform technical system for all the abovementioned treatment methods, with determination of the effectiveness of treatment and control of the treatment procedure being based on a uniform continuous ultrafiltration measurement. The device according to the invention has, inter alia, two pumps under coupled control with different delivery streams which are in an exact dosage ratio to one another. The excess occurring in the system is discharged toward the outside and recorded by a flowmeter whose the output signal is used to control a pressure-influencing element via a central control unit for regulation of the ultrafiltration rate. A change-over to pure ultrafiltration is possible by the central control unit and separately controllable valves.