BALANCED FLOW DIALYSIS MACHINE

• US 20090124963A1
• Filed: 11/09/2007
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• 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: Jablonski, Mark E., Holian, Katherine M., Childers, Robert W., Yardimci, Atif M., Busby, Donald D., Lo, Ying-Cheng, Hogard, Michael E., Roger, Rodolfo G., Ding, Yuanpang S., Maliekkal, Shincy J., Smith, Donald A., Kelly, Thomas D.
• Granted Patent: US 9,415,150 B2
• Time in Patent Office: Days
• US Class Current: 604/30
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• 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 1/15632 the filter being a dialyser
• CPC Class Codes: A61M 1/1565 Details of valves
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1635 with volume chamber balancing devices between used and fresh dialysis fluid
• CPC Class Codes: A61M 1/166 Heating for sterilisation A61M1/1686
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: A61M 1/28 Peritoneal dialysis ; Other peritoneal treatment, e.g. oxygenation
• CPC Class Codes: A61M 1/284 Continuous flow peritoneal dialysis [CFPD]
• 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 1/3413 : Diafiltration
• 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 1/3434 : 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 1/3441 : Substitution rate control as a function of the ultrafiltration rate
• 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 1/3458 : 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 1/362223 : the interface being evacuated interfaces to enhance contact
• CPC Class Codes: A61M 1/36224 : with sensing means or components thereof
• CPC Class Codes: A61M 1/362261 : 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 1/362262 : Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362264 : the filter being a blood filter
• CPC Class Codes: A61M 1/362265 : Details of valves
• CPC Class Codes: A61M 2205/12 : with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3393 : by weighing the reservoir

Abstract

A system and method for balancing flows of renal replacement fluid is disclosed. The method uses pressure controls and pressure sensing devices to more precisely meter and balance the flow of fresh dialysate and spent dialysate. The balancing system may use one or two balancing devices, such as a balance tube, a tortuous path, or a balance chamber.

Claims

1. A dialysis cassette for a renal therapy machine, the cassette 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;

fluid pathways within the housing for routing the renal failure therapy fluid; and

at least one balancing system and at least four valves operably connected to the at least one balancing system, the balancing system operably connected to the fluid pathways and to pumps for pumping the renal failure therapy fluid, the at least one balancing system configured to equalize the flow of the renal failure therapy fluid to and from a dialyzer or a patient,

wherein the cassette and the at least one balancing system are responsive to at least one pressure sensor for sensing a pressure of the renal failure therapy fluid and conveying a signal representative of the pressure to a controller of the machine, wherein the controller and the signal are configured to control the valves for a flow of renal failure therapy fluid to and from the at least one balancing system so that a pressure of the fresh renal failure therapy fluid to the at least one balancing system is equal to a pressure of spent renal failure therapy fluid to the at least one balancing system.

2. The dialysis cassette of claim 1, wherein the cassette is configured for one of hemodialysis and peritoneal dialysis and optionally, at least one temperature sensor within the cassette for sensing a temperature of the renal failure therapy fluid.

3. The dialysis cassette of claim 1, wherein at least one of the at least four valves is a pressure-regulating valve or further comprising at least one pressure regulator configured for regulating a pressure of fresh dialysis fluid or spent renal failure therapy fluid.

4. The dialysis cassette of claim 1, wherein the at least one balancing system comprises two balancing systems, the systems arranged and configured for simultaneously filling and draining of fresh and spent renal failure therapy fluid on opposite sides.

5. The dialysis cassette of claim 1, further comprising a separator in the at least one balancing system, wherein the separator is selected from the group consisting of a ball, a piston, a balloon, a wiper, and a membrane.

6. The dialysis cassette of claim 5, wherein the at least one balancing system is configured to prevent the separator from completely blocking flow into or from the at least one balancing system.

7. The dialysis cassette of claim 1, wherein the at least one pressure sensor comprises two pressure sensors, a first pressure sensor for monitoring and controlling a flow of spent renal failure therapy fluid and a second pressure sensor for monitoring and controlling a flow of fresh renal failure therapy fluid.

8. The dialysis cassette of claim 1, wherein the at least one balancing system is fabricated separately in at least two pieces and then attached to the housing.

9. The dialysis cassette of claim 1, wherein the at least one balancing system comprises at least two ports configured for removal of air bubbles from the at least one balancing system.

10. The dialysis cassette of claim 1, wherein the at least one balancing system has a form selected from the group consisting of a right cylinder, an ovate cylinder, a balloon, a bellows, and a half cylinder.

11. A dialysis cassette for a renal therapy machine, the cassette comprising:

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

a flexible membrane attached to the housing, the membrane and housing cooperating with a controller of the machine to operate valves controlling a flow of a renal failure therapy fluid;

fluid pathways within the housing for routing the renal failure therapy fluid;

at least one balancing system operably connected to the fluid pathways, and at least four valves operably connected to the at least one balancing system, wherein the at least one balancing system is configured to equalize the flow of the renal failure therapy fluid to and from a dialyzer or a patient, and optionally, a temperature sensor for sensing a temperature of the renal failure therapy fluid within the at least one balancing system; and

a separator in the at least one balancing system, the separator configured to move freely within the balancing system, wherein the controller is configured to control the valves for the flow of the renal failure therapy fluid to and from the at least one balancing system so that a pressure of the fresh renal failure therapy fluid to the at least one balancing system is equal to a pressure of spent renal failure therapy fluid to the at least one balancing system.

12. The dialysis cassette of claim 11, wherein the separator is joined to a moving cylinder or piston, and the cassette is configured so that movement of the cylinder or piston is controlled by a motor or a shaft from the renal therapy machine.

13. The dialysis cassette of claim 11, wherein the cassette further comprises at least one pressure regulating valve or pressure regulator in fluid communication with the at least one balancing system.

14. The dialysis cassette of claim 11, wherein the at least one balancing system comprises two balancing systems, and optionally, wherein a volume of the balancing systems varies during operation of the cassette.

15. A method of equalizing fluid flow in a dialysis cassette for a renal therapy machine, the method comprising:

providing a renal failure therapy machine with a controller and a dialysis cassette therefor, the cassette and the controller configured for equalizing flow of fresh and spent dialysis fluid;

sequentially pumping the fresh and spent dialysis fluid into at least one balancing system of the cassette;

optionally, selecting an operating pressure for the at least one balancing system; and

controlling a flow of the fresh and spent dialysis fluid into the at least one balancing system so that a pressure of the fresh dialysis fluid in the at least one balancing system when the at least one balancing system is filled with fresh dialysis fluid equals a pressure of the spent dialysis fluid in the at least one balancing system when the at least one balancing system is filled with spent dialysis fluid, and if an operating pressure has been selected, wherein the pressures in the at least one balancing system equal the operating pressure.

16. The method of claim 15, wherein the pressure of the fresh dialysis fluid is made to equal the pressure of the spent dialysis fluid by opening valves connecting the pressure of the fresh dialysis fluid to the pressure of the spent dialysis fluid.

17. The method of claim 15, wherein the pressure of the fresh dialysis fluid is made equal to the pressure of the spent dialysis fluid by sensing the pressure of the fresh dialysis fluid and the pressure of the spent dialysis fluid, and operating valves and pumps to equalize the pressures.

18. The method of claim 15, wherein the pressure of the fresh dialysis fluid is made equal to the pressure of the spent dialysis fluid by using a pressure regulator on an outlet of at least one of a fresh dialysate pump and a spent dialysate pump.

19. The method of claim 15, wherein the at least one balancing system further comprises a separator, and wherein the balancing system is configured for preventing the separator from completely blocking flow into and from the at least one balancing system during operation of the cassette.

20. The method of claim 15, wherein selecting an operating pressure for the at least one balancing system comprises selecting a pressure-regulating valve with an operating pressure or selecting an operating set point using the controller.

21. A method of equalizing fluid flow in a dialysis cassette for a renal therapy machine, the method comprising:

providing a renal failure therapy machine with a controller and a dialysis cassette therefor, the cassette and the controller configured for equalizing flows of fresh and spent dialysis fluid;

sequentially pumping the fresh and spent dialysis fluid into at least one balancing system of the cassette, the at least one balancing system operably connected to at least four valves for inflow and outflow of dialysis fluid;

sensing a pressure of the fresh dialysis fluid and the spent dialysis fluid in the at least one balancing system; and

controlling a flow of the fresh and spent dialysis fluid into the at least one balancing system so that a pressure of the fresh dialysis fluid in the at least one balancing system when the at least one balancing system is filled with fresh dialysis fluid equals a pressure of the spent dialysis fluid in the at least one balancing system when the at least one balancing system is filled with spent dialysis fluid.

22. The method of claim 21, wherein the at least one balancing system comprises two balancing systems, each balancing system operably connected to four valves for inflow and outflow of dialysis fluid.

23. The method of claim 21, wherein the pressure of the fresh and spent dialysis fluids are made equal by regulating the pressure of one of the fresh dialysis fluid and the spent dialysis fluid to equal the pressure of the other of the fresh dialysis fluid and the spent dialysis fluid.

24. The method of claim 21, wherein pumping fresh and spent dialysis fluid into the at least one balancing system causes movement of a separator within the at least one balancing system.

25. The method of claim 21, wherein the at least one balancing system comprises two balancing systems, each having a separator, wherein pumping fresh and spent dialysis fluid into either of the two balancing systems causes movement of the separator and a volume change in at least one of the two balancing systems.