SODIUM MANAGEMENT FOR HEMODIALYSIS

• US 20140158623A1
• Filed: 02/02/2013
• Published: 06/12/2014
• Est. Priority Date: 12/10/2012
• Status: Active Grant

• Current Assignee: Mozarc Medical US LLC
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: PUDIL, Bryant J., Gerber, Martin T., Lura, David B., Meyer, Thomas E.
• Granted Patent: US 10,905,816 B2
• Time in Patent Office: Days
• US Class Current: 210/647
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/1666 by dissolving solids
• CPC Class Codes: A61M 1/1668 Details of containers
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: A61M 1/287 Dialysates therefor
• CPC Class Codes: A61M 1/3406 Physical characteristics of the filtrate, e.g. urea
• CPC Class Codes: A61M 1/3472 with treatment of the filtrate
• CPC Class Codes: A61M 1/3479 by dialysing the filtrate
• CPC Class Codes: A61M 1/3486 Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents

Abstract

Systems and methods for managing the sodium concentration of a dialysate fluid during hemodialysis therapy and adjusting sodium concentration using a sodium management system to generate a sodium-modified fluid. The systems and methods also provide a mechanism for controlled addition of sodium ions to the dialysate to generate a predetermined total sodium concentration in a dialysate.

Claims

1. A system for kidney replacement therapy and sodium management, comprising:

a dialysate flow loop for circulating a dialysate through a dialyzer where at least one waste species enters the dialysate;

a dialysate regeneration unit for removing at least a portion of the at least one waste species and releasing at least one conductive species to the dialysate or absorbing at least one conductive species from the dialysate;

a conductivity detector that measures the conductivity or sodium ion concentration of the dialysate;

a sodium management system for generating a sodium-modified fluid for controlled addition to the dialysate in the dialysate flow loop, the sodium-modified fluid generated by the sodium management system from any one of an input dialysate, input ultrafiltrate, input solid sodium salt or input concentrated sodium resulting in a sodium ion concentration or conductivity that is higher or lower than the fluid in the dialysate flow loop.

2. The system of claim 1, wherein the sodium-modified fluid is regenerated into a physiologically-compatible dialysate, wherein only the physiologically-compatible dialysate is contacted with the blood via the dialyzer.

3. The system of claim 2, wherein the physiological compatible dialysate comprises from about 120 to about 150 mM NaCl.

4. The system of claim 2, wherein electrolytes removed from the input dialysate or input ultrafiltrate by the sodium management system are not returned or added to the dialysate in the dialysate flow loop.

5. The system of claim 1, wherein the input dialysate or input ultrafiltrate is divided into first and second flow streams within the sodium management system wherein the sodium management system generates a sodium-concentrate solution from one of the first and second flow streams, wherein the sodium-concentrate solution can be passed through a dialysate regeneration unit to regenerate one or more materials or sorbents located therein;

an ultrafiltrate reservoir for pumping fluid into or out of the dialysate flow loop at a position downstream from the dialyzer and upstream from the dialysate regeneration unit, wherein operation of the control pump in an efflux direction causes net removal of fluid from the blood on an extracorporeal side of a membrane in the dialyzer to generate an ultrafiltrate added to the ultrafiltrate reservoir and operation of the control pump in an influx direction causes net addition of fluid to the blood on the extracorporeal side of the membrane.

6. The system of claim 1, wherein the sodium management system is an electrodialysis cell comprising at least a concentrate flow channel, a diluate flow channel and an electrode rinse flow channel, wherein sodium ions move from the diluate flow channel to the concentrate flow channel in response to an electric field wherein the sodium-modified fluid is generated in the diluate flow channel for addition to the dialysate flow loop.

7. The system of claim 6, wherein the diluate flow channel is defined by a cation and an anion exchange membrane, the concentrate flow channel is defined by a cation and anion exchange membrane, and an electrode rinse channel is defined by a cation exchange membrane wherein the diluate flow channel is separated from the one or more concentrate flow channel by either a cation or anion exchange membrane.

8. The system of claim 6, further comprising an electrode rinse pump and electrode rinse reservoir for circulating the electrode rinse solution through the electrode rinse flow channel.

9. The system of claim 6, further comprising a concentrate solution and a concentrate pump for circulating the concentrate through the concentrate flow channel and an electrode rinse pump and electrode rinse reservoir for circulating the electrode rinse solution through the electrode rinse flow channel.

10. The system of claim 1, wherein ultrafiltrate directed toward the ultrafiltrate reservoir passes through the sodium management system prior to collection in the ultrafiltrate reservoir.

11. The system of claim 1, wherein the dialysate flow loop further comprises a dialysate reservoir located downstream from the dialyzer and upstream from the dialysis regeneration unit.

12. The system of claim 6, wherein the ultrafiltrate passes through the concentrate flow channel prior to collection in the ultrafiltrate reservoir.

13. The system of claim 6, wherein a first flow stream passes through the concentrate flow channel prior to collection in an ultrafiltrate reservoir and a second flow stream passes through the diluent flow channel to generate the sodium-modified solution for addition to the dialysate flow loop.

14. The system of claim 1, further comprising a sodium management pump for directing fluid from the ultrafiltrate reservoir to the sodium management system for addition to the dialysate in the dialysate flow loop.

15. The system of claim 1, wherein the sodium-modified fluid has a sodium ion conductivity or concentration less than the dialysate in the dialysate flow loop and thereby reduces the concentration of sodium in the dialysate flow loop upon addition to the dialysate.

16. The system of claim 1, wherein the sodium management system modifies the conductivity or sodium ion concentration by application of an electrical field.

17. The system of claim 1, wherein the sodium management system generates the sodium-modified fluid from dialysate removed from the dialysate flow loop.

18. The system of claim 17, wherein dialysate from the dialysate flow loop is directed through the sodium management system or bypasses the sodium management system using a bypass regulator.

19. The system of claim 1, wherein sodium-modified fluid from the sodium management system is added to the dialysate flow loop at a position between an outlet of the dialyzer and an inlet of the dialysate regeneration unit.

20. The system of claim 1, wherein sodium-modified fluid from the sodium management system is added to the dialysate flow loop at a position between an inlet of the dialyzer and an outlet of the dialysate regeneration unit.

21. The system of claim 1, wherein the sodium management system comprises a forward osmosis system having a reverse osmosis module, and a water reservoir.

22. The system of claim 1, wherein the sodium management system comprises a reverse osmosis system comprising a reverse osmosis module having a sodium rejection fraction greater than 95%.

23. The system of claim 1, wherein the sodium management system comprises a capacitive deionization cell.

24. The system of claim 23, wherein the capacitive deionization cell can remove sodium ions for generating a sodium-modified fluid having a lower concentration than the fluid entering the capacitive deionization cell.

25. The system of claim 23, wherein the capacitive deionization cell can store sodium ions for generating a sodium-modified fluid having a higher concentration than the fluid entering the capacitive deionization cell.

26. The system of claim 23, wherein the sodium management system comprise at least two capacitive deionization cells, wherein one capacitive deionization cell can be regenerated by passing a flushing fluid through the capacitive deionization cell while the other capacitive deionization remains operable to generate the sodium-modified fluid.

40. The system of claim 1, wherein the system is controlled compliant.

41. The system of claim 1, wherein the system selectively meters fluid into and out of the dialysate flow loop.

42. The system of claim 1, wherein the system selectively meters fluid into and out of the dialysate flow loop using any one of a control pump, a water pump, a salination pump, an acid concentrate pump, a replacement fluid pump, and combinations thereof.

43. The system of claim 1, wherein the system provides for bi-directional flow.

27. A method for modifying the sodium concentration of a dialysate for dialyzing blood, comprising:

circulating a dialysate in a dialysate flow loop wherein the dialysate contacts a dialyzer wherein a waste species enters the dialysate and a dialysate regeneration unit wherein at least one waste species is partially removed by the dialysate regeneration unit;

operating a control or ultrafiltration pump connected to an ultrafiltrate reservoir for pumping fluid into or out of the dialysate flow loop at a position downstream from the dialyzer and upstream from the dialysate regeneration unit, wherein operation of the control pump in an efflux direction causes net removal of fluid from the blood on an extracorporeal side of a membrane in the dialyzer to generate an ultrafiltrate added to the ultrafiltrate reservoir and operation of the control pump in an influx direction causes net addition of fluid to the blood on the extracorporeal side of the membrane;

modifying the sodium concentration of an input fluid using a sodium management system through application of an electrical field to generate a sodium-modified fluid, the input fluid being dialysate or ultrafiltrate and the input fluid divided into first and second flow streams within the sodium management system; and

adding the sodium-modified fluid to the dialysate flow loop.

28. The method of claim 27, wherein the input fluid is a fluid removed from the dialysate flow loop at a location between an outlet of the dialysate regeneration unit and an inlet of the dialyzer.

29. The method of claim 27, wherein the input fluid is a fluid removed from the dialysate flow loop at a location between an inlet of the dialysate regeneration unit and an outlet of the dialyzer.

30. The method of claim 27, wherein the input fluid is an ultrafiltrate removed from dialysate flow loop through operation of the control or ultrafiltrate pump.

31. The method of claim 27, wherein the sodium-modified solution is added to the dialysate flow loop at a location between an outlet of the dialysate regeneration unit and an inlet of the dialyzer.

32. The method of claim 27, wherein the sodium-modified solution is added to the dialysate flow loop at a location between an inlet of the dialysate regeneration unit and an outlet of the dialyzer.

33. The method of claim 27, wherein the sodium management system has an electrodialysis cell with at least a concentrate flow channel, a diluate flow channel and an electrode rinse flow channel, wherein sodium ions move from the diluate flow channel to the concentrate flow channel in response to an electric field wherein the sodium-modified fluid is generated in the diluate flow channel for addition to the dialysate flow loop.

34. The method of claim 27, further comprising operating the control pump to transport ultrafiltrate through the concentrate flow channel to the ultrafiltrate reservoir.

35. The method of claim 33, wherein the first flow stream is passed through the concentrate flow channel prior to collection in the ultrafiltrate reservoir and the second flow stream is passed through the diluent flow channel to generate the sodium-modified solution for addition to the dialysate flow loop.

36. The method of claim 27, wherein the input fluid has a pH greater than 7.0.

37. The method of claim 27, with the proviso that the input fluid is substantially free of ammonia or ammonium ions.

38. The method of claim 27, with the proviso that any addition of fluid having a sodium ion concentration higher than the dialysate in the dialysate flow loop to increase the sodium ion concentration therein is the sodium-modified fluid generated by the sodium management system using a capacitive deionization cell.

39. The method of claim 27, with the proviso that any addition of fluid having a sodium ion concentration lower than the dialysate in the dialysate flow loop to decrease the sodium ion concentration therein is the sodium-modified fluid generated by the sodium management system using a capacitive deionization cell.

44. The method of claim 27, wherein the method is controlled compliant.

45. The method of claim 27, wherein fluid is selectively metered into and out of the dialysate flow loop.

46. The method of claim 27, wherein the fluid is selectively metered into and out of the dialysate flow loop using any one of a control pump, a water pump, a salination pump, an acid concentrate pump, a replacement fluid pump, and combinations thereof.

47. The method of claim 27, wherein bi-directional flow is provided with the dialysate flow loop.