High convection home hemodialysis/hemofiltration and sorbent system

• US 20050131332A1
• Filed: 11/04/2004
• Published: 06/16/2005
• Est. Priority Date: 11/05/2003
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Sayyid, Waleed Mutasem El, Childers, Robert W., Din, Shahid, Kelly, Thomas, Busby, Don, Roger, Rodolfo
• Granted Patent: US 8,029,454 B2
• Time in Patent Office: Days
• US Class Current: 604/4.10
• CPC Class Codes: A61M 1/1522 the interface being evacuated interfaces to enhance contact
• CPC Class Codes: A61M 1/153 the cassette being adapted for heating or cooling the treating fluid, e.g. the dialysate or the treating gas
• CPC Class Codes: A61M 1/154 with sensing means or components thereof
• CPC Class Codes: A61M 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/1561 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/15625 the reservoirs acting as balance chambers
• CPC Class Codes: A61M 1/1563 Details of incorporated filters
• CPC Class Codes: A61M 1/1565 Details of valves
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1601 Control or regulation
• CPC Class Codes: A61M 1/1607 before use, i.e. upstream of dialyser
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1621 Constructional aspects thereof semi-permeable membranes for separation processes characterised by their properties B01D69/00; semi permeable membranes characterised by their material B01D71/00
• CPC Class Codes: A61M 1/1629 with integral heat exchanger
• CPC Class Codes: A61M 1/1633 with more than one dialyser unit
• CPC Class Codes: A61M 1/1635 with volume chamber balancing devices between used and fresh dialysis fluid
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/166 Heating for sterilisation A61M1/1686
• CPC Class Codes: A61M 1/1668 Details of containers
• CPC Class Codes: A61M 1/167 Flexible packaging for solid concentrates
• CPC Class Codes: A61M 1/1672 : using membrane filters, e.g. for sterilising the dialysate
• CPC Class Codes: A61M 1/1696 : with dialysate regeneration
• CPC Class Codes: A61M 1/267 : used for pumping
• CPC Class Codes: A61M 1/288 : Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 1/3401 : Cassettes therefor
• CPC Class Codes: A61M 1/341 : by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3417 : using distinct filters for dialysis and ultra-filtration
• CPC Class Codes: A61M 1/342 : Adding solutions to the blood, e.g. substitution solutions for preventing coagulation A61M1/3672
• CPC Class Codes: A61M 1/3427 : back through the membrane, e.g. by inverted trans-membrane pressure [TMP]
• CPC Class Codes: A61M 1/3431 : upstream of the filter
• CPC Class Codes: A61M 1/3434 : with pre-dilution and post-dilution
• CPC Class Codes: A61M 1/3437 : downstream of the filter, e.g. post-dilution with filtrate
• CPC Class Codes: A61M 1/3444 : in which the collected ultra-filtrate expels an equal volume of substitution fluid from a reservoir
• CPC Class Codes: A61M 1/3451 : the difference in weight between both ultra-filtrate and substitution reservoir being used as control signal
• CPC Class Codes: A61M 1/3458 : having electrolytes not present in the dialysate
• CPC Class Codes: A61M 1/3465 : using dialysate as substitution fluid
• CPC Class Codes: A61M 1/3468 : using treated filtrate as substitution fluid
• CPC Class Codes: A61M 1/3472 : with treatment of the filtrate
• CPC Class Codes: A61M 1/3486 : Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents
• CPC Class Codes: A61M 1/3621 : Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 1/362223 : the interface being evacuated interfaces to enhance contact
• CPC Class Codes: A61M 1/36224 : with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 : with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 : at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362265 : Details of valves
• CPC Class Codes: A61M 1/3624 : Level detectors; Level control
• CPC Class Codes: A61M 1/3626 : Gas bubble detectors
• CPC Class Codes: A61M 1/3627 : Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 1/3643 : Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 : Mode of operation
• CPC Class Codes: A61M 1/3646 : Expelling the residual body fluid after use, e.g. back to the body
• CPC Class Codes: A61M 1/3647 : with recirculation of the priming solution
• CPC Class Codes: A61M 1/3649 : using dialysate as priming or rinsing liquid
• CPC Class Codes: A61M 1/365 : through membranes, e.g. by inverted trans-membrane pressure [TMP]
• CPC Class Codes: A61M 1/3652 : using gas, e.g. air
• CPC Class Codes: A61M 1/3656 : Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 2202/0413 : Blood
• CPC Class Codes: A61M 2205/12 : with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/127 : with provisions for heating or cooling
• CPC Class Codes: A61M 2205/13 : with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/15 : Detection of leaks
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/276 : preventing unwanted use
• CPC Class Codes: A61M 2205/3317 : Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3324 : PH measuring means
• CPC Class Codes: A61M 2205/3327 : Measuring
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3337 : Controlling, regulating pressure or flow by means of a valve by-passing a pump
• CPC Class Codes: A61M 2205/3344 : Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3379 : Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/3393 : by weighing the reservoir
• CPC Class Codes: A61M 2205/3553 : remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3561 : local, e.g. within room or hospital
• CPC Class Codes: A61M 2205/3584 : using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/502 : User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 : with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/75 : with filters
• CPC Class Codes: A61M 60/113 : in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/258 : Piston pumps
• CPC Class Codes: A61M 60/279 : Peristaltic pumps, e.g. roller pumps
• CPC Class Codes: A61M 60/37 : Haemodialysis, haemofiltration or diafiltration
• CPC Class Codes: A61M 60/43 : using vacuum at the blood pump, e.g. to accelerate filling
• CPC Class Codes: A61M 60/508 : Electronic control means, e.g. for feedback regulation
• CPC Class Codes: A61M 60/847 : arranged in a cassette
• CPC Class Codes: A61M 60/849 : Disposable parts
• CPC Class Codes: A61M 60/851 : Valves

Abstract

A system, method and apparatus for performing a renal replacement therapy is provided. In one embodiment, two small high flux dialyzers are connected in series. A restriction is placed between the two dialyzers in the dialysate flow path. The restriction is variable and adjustable in one preferred embodiment. The restriction builds a positive pressure in the venous dialyzer, causing a high degree of intentional backfiltration. That backfiltration causes a significant flow of dialysate through the high flux venous membrane directly into the patient'"'"'s blood. That backfiltered solution is subsequently ultrafiltered from the patient from the arterial dialyzer. The diffusion of dialysate into the venous filter and removal of dialysate from the arterial dialyzer causes a convective transport of toxins from the patient. Additionally, the dialysate that does not diffuse directly into the patient but instead flows across the membranes of both dialyzers provides a diffusive clearance of waste products.

Claims

1. A medical fluid therapy system comprising:

a blood line configured and arranged to be coupled to a patient;

a pump connected to the blood line;

a first dialyzer portion in communication with the blood line and positioned to receive blood from the patient;

a second dialyzer portion positioned to receive blood from the first dialyzer portion;

a therapy fluid line connected to a therapy fluid source and in fluid communication with the first and second dialyzer portions; and

a flow restriction in communication with the therapy fluid line between the first and second dialyzer portions, the restriction variable to selectively increase/decrease backpressure of the therapy fluid in one of the first and second dialyzer portions.

2. The medical fluid therapy system of claim 1, wherein the first portion, second portion and restriction are provided in a single housing.

3. The medical fluid therapy system of claim 1, wherein the first portion and second portion are housed separately.

4. The medical fluid therapy system of claim 1, which includes a device coupled to the flow restriction, the device operable to vary the fluid flow resistance of the flow restriction.

5. The medical fluid therapy system of claim 4, wherein the device is operated manually or automatically.

6. The medical fluid therapy system of claim 1, wherein at least a portion of at least one of the blood line and therapy fluid line is disposable.

7. The medical fluid therapy system of claim 1, wherein at least one of the first portion, second portion and flow restriction are disposable.

8. The medical fluid therapy of claim 1, further comprising a disposable cassette that includes at least one of the first portion, second portion, flow restriction, a blood line portion and a therapy fluid line portion.

9. The medical fluid therapy system of claim 1, wherein the pump is a first pump and which includes at least one additional pump configured and arranged to pump the therapy fluid.

10. The medical fluid therapy system of claim 9, wherein the additional pump is of a type selected from the group consisting of:

a membrane pump, a peristaltic pump, a piston pump, a pneumatically actuated pump, a piston pump, a pneumatically activated pump and any combination thereof.

11. The medical fluid therapy system of claim 9, which includes a pair of the additional pumps operating on opposite cycle strokes to deliver therapy fluid to the dialyzer portions.

12. The medical fluid therapy system of claim 9, which includes at least one of the additional pumps operable to deliver therapy fluid to one of the dialyzer portions and at least one other of the additional pumps operable to remove ultrafiltrate from the other dialyzer portion.

13. The medical fluid therapy system of claim 1, which includes at least one fluid flow management apparatus of a type selected from the group consisting of:

a capacitance fluid volume sensor, a fluid volume sensor operation based on the ideal gas law, a sensor that counts a number of revolutions/strokes made by a peristaltic pump, a weighing scale, a single balance chamber, a single balance tube, a single tortuous path, a dual balance chamber, a dual balance tube and a dual tortuous path.

14. The medical fluid therapy system of claim 1, which includes a fluid heater in communication with the therapy fluid line that heats the therapy fluid before the fluid reaches one of the first and second dialyzer portions.

15. The medical fluid therapy system of claim 14, wherein the heater is of at least one type selected from the group consisting of:

inductive, electrical resistance, convective and radiant.

16. The medical fluid therapy system of claim 1, wherein the therapy fluid source includes at least one portable fluid container, a therapy fluid preparation module, an on-line therapy fluid source and any combination thereof.

17. The medical fluid therapy system of claim 1, wherein the restriction is sized to backflow from ten to ninety percent of the fluid through one of the dialyzers into the blood line.

18. The medical fluid therapy system of claim 1, which includes at least one air sensing and/or removal device in the blood line.

19. The medical fluid therapy system of claim 1, which performs a therapy selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration and any combination thereof.

20. The medical fluid therapy system of claim 19, wherein the hemofiltration therapy is a predilution therapy, a postdilution therapy or a pre- and postdilution therapy.

21. The medical fluid therapy system of claim 1, which includes a recirculation loop in communication with the therapy fluid line, wherein fluid removed from one of the dialyzers is reintroduced into the therapy fluid line to communicate fluidly again with one of the first and second dialyzers.

22. The medical fluid therapy system of claim 21, wherein the recirculation line reintroduces the fluid into the dialyzer from which the fluid is removed.

23. The medical fluid therapy system of claim 21, wherein fluid is removed for the recirculation loop from the dialyzer located downstream from the restriction.

24. The medical fluid therapy system of claim 21, which includes at least one cleaning device located in the recirculation loop, the device operating to at least partially regenerate the fluid to be reintroduced into the therapy fluid line.

25. The medical fluid therapy system of claim 24, wherein the cleaning device is selected from the group consisting of:

an activated charcoal filter, a sorbent exchange, a chemical cleaner, a chemical exchange, a biological cleanser, a binding adsorption agent, an enzomatic reaction agent, a mechanical cleaner and any combination thereof.

26. The medical fluid therapy system of claim 1, wherein therapy fluid flows through the first and second portions counter-current to the flow of blood.

27. The medical fluid therapy system of claim 1, wherein therapy fluid flows through the first and second portions co-current to the flow of blood.

28. The medical fluid therapy system of claim 1, wherein the variable restriction includes a motor controlled clamp.

29. A medical fluid therapy system comprising:

a blood line configured and arranged to be coupled to a patient;

a pump connected to the blood line;

a first dialyzer in communication with the blood line and positioned to receive blood from the patient;

a second dialyzer housed separately from the first dialyzer, the second dialyzer positioned and arranged to receive blood from the first dialyzer; and

a flow restriction in communication with the therapy fluid line between the first and second dialyzers, the restriction operable to increase backpressure of the therapy fluid in one of the first and second dialyzers.

30. The system of claim 29, wherein the restriction is variable to selectively increase/decrease the backpressure.

31. A disposable unit for a renal failure therapy machine comprising:

a housing configured and arranged to be placed in the machine;

a flexible membrane attached to the housing, the membrane and housing cooperating with the machine to perform a valving function controlling flow of a renal failure therapy fluid;

first and second dialyzer portions carried by the housing and connected operably to at least a portion of a patient blood line; and

a flow restriction placed between the first and second dialyzers, the restriction operable to increase backpressure in one of the dialyzers.

32. The disposable unit of claim 31, wherein the dialyzer portions are housed separately.

33. The disposable unit of claim 31, wherein the blood line includes a length of tubing configured to couple operably with a peristaltic pump housed in the machines.

34. The disposable unit of claim 31, which includes at least one fluid flow management apparatus of a type selected from the group consisting of:

a capacitance fluid volume sensor, a fluid volume sensor operation based on the ideal gas law, a sensor that counts a number of revolutions/strokes made by a peristaltic pump, a weighing scale, a single balance chamber, a single balance tube, a single tortuous path, a dual balance chamber, a dual balance tube and a dual tortuous path.

35. A medical fluid therapy method comprising the steps of:

(a) causing therapy fluid to flow to first and second dialyzer portions;

(b) placing a variable flow restriction between the first and second portions; and

(c) setting the variable flow restriction so that a desirable first portion of the fluid flows into a blood line through one of the dialyzers and a second portion of the fluid flows substantially across a plurality of membranes located in the second dialyzer.

36. The medical fluid therapy method of claim 35, wherein setting the restrictions further causes a third portion of the fluid to flow across membranes located in the first dialyzer portion.

37. A home medical fluid therapy machine method comprising the steps of:

(a) enabling a person at home to load a disposable cassette in the machine;

(b) causing therapy fluid to flow to the disposable cassette;

(c) directing at least twenty-five percent of the fluid to perform conductive clearance; and

(d) enabling at least a substantial amount of the remaining fluid to perform diffusive cleaning.

38. The home medical fluid therapy method of claim 37, wherein directing the percentage of the fluid to perform conductive cleaning includes causing the fluid percentages to be backpressured through a dialyzer membrane into the patient'"'"'s blood flow.

39. A method of performing ultrafiltration comprising:

providing first and second balancing devices;

pumping spent therapy fluid into the first balancing device;

enabling therapy fluid expelled from the first balancing device by the spent therapy fluid pumped into the first balancing device to flow to the second balancing device; and

enabling the expelled therapy fluid entering the second balancing device to expel spent therapy fluid held in the second balancing device to drain.

40. The method of claim 39, wherein the spent and expelled therapy fluids are selected form the group consisting of:

dialysate and substitution fluid.

41. The method of claim 39, wherein the balancing devices are selected from the group consisting of:

balance chambers, balance tubes and tortuous paths.

42. The method of claim 39, wherein the therapy fluid expelled from the first balancing device is fresh therapy fluid.

43. A valve integrity test for a fluid pump placed in line with inlet and outlet valves, the test comprising the steps of:

(a) pumping fluid into a pump with the outlet valve closed and the inlet valve open;

(b) closing the inlet valve while keeping the outlet valve closed;

(c) attempting to pump fluid from the pump with the valves closed; and

(d) determining that at least one of the valves is leaking if a volume change of fluid within the pump is detected.

44. The integrity test of claim 43, which includes using a capacitance fluid volume sensor to detect whether the volume change within the pump occurs.

45. The integrity test of claim 43, which includes performing steps (a) to (d) periodically throughout a medical fluid therapy.

46. The integrity test of claim 43, which includes performing steps (a) to (c) for a therapy selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration, peritoneal dialysis and any combination thereof.

47. A method of sensing volume on a real time basis comprising:

obtaining an initial air total volume that includes a volume of air in a membrane pump chamber and a volume of air in a constant volume vessel in communication with the pump chamber;

moving the membrane in the pump chamber to dispel fluid from or draw fluid into the pump chamber;

measuring an initial pressure and a pressure at time T after the total volume has changed;

calculating the total air volume for the time T using the initial total volume, the initial pressure and the pressure at time T; and

determining the volume pumped using the initial air total volume and the total air volume for the time T.

48. The method of claim 47, wherein the constant volume vessel is a pressure chamber.

49. A medical fluid therapy system comprising:

a blood line configured and arranged to be coupled to a patient;

a blood pump connected to the blood line;

a blood filter in communication with the blood line, the filter operable to allow a liquid portion of a patient'"'"'s blood to pass from the filter to a therapy fluid flow path;

a pair of peristaltic fluid pumps positioned and arranged to alternatively and substantially continuously pump therapy fluid to and from the blood line; and

at least one volume control device operable to control an amount of therapy fluid that is pumped to the blood line and an amount of the fluid is pumped from the filter.

50. The medical fluid therapy system of claim 49, which includes a plurality of valves operable to enable the peristaltic pumps to perform the alternating and substantially continuous pumping of the therapy fluid.

51. The medical fluid therapy system of claim 49, which is operably to selectively pump therapy fluid to the blood line upstream or downstream of the filter.

52. The medical fluid therapy system of claim 49, which is configured to pump therapy fluid to the filter to perform convective and/or diffusive blood clearance.

53. The medical fluid therapy system of claim 49, wherein the volume control device is of a type selected from the group consisting of:

a capacitance fluid volume sensor, a fluid volume sensor operation based on the ideal gas law, a sensor that counts a number of revolutions/strokes made by a peristaltic pump, a weighing scale, a single balance chamber, a single balance tube, a single tortuous path, a dual balance chamber, a dual balance tube and a dual tortuous path.

54. A medical fluid therapy system comprising:

a blood line configured and arranged to be coupled to a patient;

a blood pump connected to the blood line;

a blood filter in communication with the blood line, the filter operable to allow a liquid portion of a patient'"'"'s blood to pass from the filter to a therapy fluid flow path;

a first pump operable to pump therapy fluid to the blood line;

a second pump operable to pump fluid from the filter; and

a recirculation path operable to direct at least some of the fluid pumped from the filter, through a fluid regeneration device, into the blood line.

55. The medical fluid therapy system of claim 54, wherein the regeneration device includes activated charcoal, a sorbent of any combination thereof.

56. The medical fluid therapy system of claim 54, which is operable to selectively pump therapy fluid to the blood line upstream or downstream of the filter.

57. The medical fluid therapy system of claim 54, which is configured additionally to pump therapy fluid to the filter to perform diffusive blood clearance.