Peritoneal dialysis methods and apparatus

• US 20070179431A1
• Filed: 01/30/2007
• Published: 08/02/2007
• Est. Priority Date: 01/30/2006
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California), U.S. Government Represented By The Department Of Veterans Affairs
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Roberts, Martin, Lee, David B.N.
• Granted Patent: US 8,187,250 B2
• Time in Patent Office: Days
• US Class Current: 604/29
• CPC Class Codes: A61M 1/1686 by heat
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: A61M 1/28 Peritoneal dialysis ; Other peritoneal treatment, e.g. oxygenation

Abstract

A peritoneal-based (“bloodless”) artificial kidney processes peritoneal fluid without need for additional fluids (“waterless”). Fluid is separated into a protein-rich stream and a protein-free stream. The protein-rich stream is regenerated using a sorbent assembly, and its protein composition can be modified by removal of selected protein(s) (“dialysate-pheresis”). It is then reconstituted with additives and returned into the peritoneal cavity, thereby reducing protein-loss and providing oncotic-pressure for ultrafiltration. The protein-free stream is used to produce free water, and an alkaline or acid fluid for optimization of the composition of the regenerated stream. The unused protein-free stream can be used to “reverse flush” the separator to maintain its patency and the excess discarded for fluid-balance regulation. Compared to prior art, immobilization of urease allows more protein rich fluid to be regenerated and re-circulated into the peritoneal cavity for toxin removal and allows practicable development of portable and wearable artificial kidneys.

Claims

1. A system, comprising:

a first fluid line that carries a fluid stream from a peritoneal cavity of the user;

a separator that separates the fluid stream into a relatively protein-rich stream and a relatively protein-free stream, wherein the relatively protein-rich stream averages at least 15 vol % of the fluid stream over at least some period time; and

a processing line that processes at least some of the relatively protein-rich stream to produce a modified dialysate stream; and

a second fluid line that introduces at least some of the modified dialysate stream into the peritoneal cavity.

2. The system of claim 1, wherein the relatively protein-rich stream averages at least 40 vol % of the spent dialysate stream over the at least some period of time.

3. The system of claim 1, wherein the relatively protein-rich stream averages at least 90 vol % of the spent dialysate stream over the at least some period of time.

4. The system of claim 1, wherein the separator comprises a hollow fiber filter.

5. The system of claim 1, further comprising a pump that at least temporarily affects a ratio of the relatively protein-rich stream to the relatively protein-free stream.

6. The system of claim 1, wherein the processing line includes a sorbent system that removes at least one toxin from at least some of the protein-rich stream.

7. The system of claim 6, wherein at least some of the sorbent system includes an enzyme that is immobilized on a substrate with greater than Van der Waals forces.

8. The system of claim 1, wherein the sorbent system comprises a user-replaceable assembly having at least 100 gm of a sorbent.

9. The system of claim 1, wherein the processing line includes a processor comprising at least one of a cation exchanger and an anion exchanger, which alters a concentration in at least a portion of the relatively protein-free stream of at least one of H⁺, OH⁻

, CO₃⁻

and HCO₃⁻

.

10. The system of claim 1, wherein the processing line includes a gas extractor disposed to operate upon at least a portion of the relatively protein-rich stream.

11. The system of claim 1, wherein the processing line includes a sterilizer disposed to operate upon at least a portion of the relatively protein-rich stream.

12. The system of claim 1, further comprising at least one monitor that measures a characteristic of the system, and a circuit that operates a signaler when the characteristic falls outside of a desired range.

13. The system of claim 1, further comprising a sodium monitor and feedback loop that maintains an average sodium concentration of at least a portion of the relatively protein-rich stream within a desired range over a period of at least 1 hour.

14. The system of claim 1, further comprising a pH monitor and feedback loop that maintains an average pH of at least a portion of the relatively protein-rich stream within a desired range over a period of at least 1 hour.

15. The system of claim 1, further comprising an ammonia detector and feedback loop that triggers an action when an ammonia concentration in at least a portion of the relatively protein-rich stream is greater than 2 mg %.

16. The system of claim 1, further comprising a glucose addition module, and at least one enrichment module that collectively adds at least two of potassium, calcium, and magnesium to at least a portion of the relatively protein-rich stream.

17. The system of claim 1, further comprising a unit that targets removal of a specific protein from at least a portion of the relatively protein-rich stream.

18. The system of claim 1, further comprising an ultrasonic vibrator that operates upon at least a portion of the relatively protein-rich stream.

19. The system of claim 1, wherein the second fluid line is operable concurrently with the first fluid line.

20. The system of claim 1, wherein the processing line, excluding a user-replaceable sorbent cartridge, has a dry weight of no more than 5 kg.

21. The system of claim 1, wherein the user-replaceable sorbent assembly has a dry weight of no more than 5 kg.

22. The system of claim 1, wherein the processing line excluding a user-replaceable sorbent assembly has a dry weight of no more than 2 kg.

23. The system of claim 1, wherein the user-replaceable sorbent assembly has a dry weight of no more than 2 kg.

24. The system of claim 1, wherein the processing line includes a hydrophobic/hydrophilic membrane disposed to operate upon at least a portion of the relatively protein-rich stream.

25. The system of claim 1, further comprising a power source sufficient to operate the processing line continuously for at least 8 hours.

26. A method of processing a substantially blood-free fluid derived from a peritoneal cavity of a person, comprising:

separating the substantially blood-free fluid into a relatively protein-rich fluid and a relatively protein-free fluid;

processing the relatively protein-rich fluid with a sorbent having an at least substantially immobilized urease to produce a purified regenerated) fluid; and

depositing at least some of the purified fluid back into the peritoneal cavity.

27. The method of claim 26, wherein the step of reintroducing occurs concurrently with the step of separating.

28. The method of claim 26, wherein the step of reintroducing occurs intermittently with the step of separating.

29. The method of claim 26, further comprising using a filter to filter out the relatively protein-free fluid from the relatively protein-rich fluid.

30. The method of claim 26, further comprising controlling at least two of:

(a) a cation in the purified fluid;

(b) an anion in the purified fluid;

(c) a gas; and

(d) a glucose level in the purified fluid.

31. The method of claim 26, further comprising re-circulating to the person at least 80% of the substantially blood-free fluid as the purified fluid over a period of 4 hours.

32. The method of claim 26, further comprising re-circulating at least 90% of the substantially blood-free fluid as the purified fluid over a period of 8 hours.

33. The method of claim 26, further comprising re-circulating the substantially blood-free fluid as the purified fluid at a rate sufficient to provide at least 20 liters of purified fluid over a 10 hour period.

34. The method of claim 26, further comprising re-circulating the substantially blood-free fluid as the purified fluid at a rate sufficient to provide at least 48 liters of purified fluid over a 24 hour period.

35. The method of claim 26, wherein the step of processing occurs at least 40 hours during a period of seven consecutive days.

36. The method of claim 26, wherein the step of processing occurs at least 126 hours during a period of seven consecutive days.

37. The method of claim 26, further comprising embodying the processing steps in a device, and the person wearing the device.

38. The method of claim 26, further comprising processing at least a portion of the relatively protein-free fluid through at least one of a reverse osmosis unit and an ion-exchanger, and then adding a resulting product into a stream containing the relatively protein-rich fluid.