Device for regulating at least one filtration value, haemodialysis machine and corresponding method and use
The present invention relates to an apparatus for the regulation of at least one filtration value in a machine for the treatment of a medical fluid, in particular in a blood treatment machine, having at least one centrifugal pumping means, to a hemodialysis machine and to a method and to a use therefor.
1. A method for the regulation of at least one blood filtration value in a machine cooperating with a disposable cassette for the treatment of blood in an extracorporeal blood circuit having at least one centrifugal blood pump, characterized in that the centrifugal blood pump has a driving part located in the machine and a driven part located in the disposable cassette and coupled with the driving part in a contactless manner, wherein the machine comprises a control device for regulating speed of the centrifugal blood pump, and characterized in that the viscosity of the blood is determined indirectly and/or directly by speed and driving torque of the centrifugal blood pump downstream of a blood filter, hematocrit of the blood is determined based solely on the viscosity determined, and with the at least one blood filtration value being regulated directly or indirectly by the control device with reference solely to the hematocrit determined based on viscosity.
2. A method in accordance with claim 1 , characterized in that the centrifugal blood pump is operated in at least one conveying mode and/or at least one measurement mode.
3. A method for regulating filtration of blood in a machine cooperating with a disposable cassette in an extracorporeal blood circuit comprising the steps of
determining viscosity of the blood indirectly or directly based on speed and driving torque of a centrifugal blood pump downstream of a blood filter, the centrifugal blood pump having a driving part located in the machine and a driven part located in the disposable cassette and coupled with the driving part in a contactless manner, wherein the machine comprises a control device for regulating speed of the centrifugal blood pump,
determining hematocrit of the blood based solely on the determined viscosity, and
regulating directly or indirectly by the control device at least one blood filtration value based solely on the determined hematocrit based on viscosity.
4. The method of claim 3 , wherein the centrifugal blood pump is operated in at least one of a conveying mode, a measurement mode, multiple conveying modes, and multiple measurement modes.
5. The method of claim 3 , wherein the driving part transmits torque by a magnetic coupling to the driven part.
6. The method of claim 3 , wherein the machine for the treatment of blood is a hemodialysis machine, and wherein the at least one filtration value is at least one of ultrafiltration rate and ultrafiltration goal.
7. The method of claim 3 , wherein the blood filtration value is blood volume flow.
8. The method of claim 3 , wherein the centrifugal blood pump has an inlet and an outlet, at least one of the inlet and the outlet capable of closing.
9. The method of claim 8 , wherein the centrifugal blood pump operates in a measurement mode when at least one of the inlet and outlet is closed.
10. The method of claim 8 , wherein the filtration value is volume flow of the blood determined by at least one flow measurement sensor arranged downstream or upstream of the centrifugal blood pump.
11. The method of claim 8 , wherein the viscosity is determined by circulating the blood in the centrifugal blood pump at a speed of 200 r.p.m. or less.
12. The method of claim 3 , wherein the machine is a hemodialysis machine.
13. The method of claim 12 , wherein the hemodialysis machine has a mount holding the disposable cassette.