Synchronized volumetric fluid balancing systems and methods

• US 6,638,478 B1
• Filed: 02/25/2000
• Issued: 10/28/2003
• Est. Priority Date: 02/14/1997
• Status: Expired due to Term

• Current Assignee: Nxstage Medical Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Nxstage Medical Incorporated (Fresenius SE & Co. KGaA)
• Inventors: Treu, Dennis M, Finch, Charles D., Thomas, Robert, Burbank, Jeffrey H., Brugger, James
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): Bianco, Patricia
• Application Number:
  US09/513,911
• Time in Patent Office: 1,341 Days
• Field of Search: 604/4.01, 604/5-1-, 604/6.01, 604/6.09, 604/6.1, 604/6.11, 604/6.16, 604/30-31, 604/65-67, 604/81, 604/131-33, 604/151-55, 604/403-16, 422/44, 210/645-47, 210/650-52, 210/739, 210/741, 210/744, 210/767, 210/790, 210/805, 210/85, 210/87-90, 210/97, 210/98, 210/252-53, 210/257--, 210/258-262, 210/256, 210/321.6, 210/321-1-, 210/929, 210/416.1, 210/417-18, 210/420, 210/194, 210/102, 210/195.1, 137/825-26, 137/98, 137/109, 137/110, 137/247, 137/627-28, 137/599.01
• US Class Current: 422/44
• CPC Class Codes: A61M 1/1639 linked by membranes
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3401 Cassettes therefor
• CPC Class Codes: A61M 1/3403 Regulation parameters
• CPC Class Codes: A61M 1/342 Adding solutions to the blood, e.g. substitution solutions for preventing coagulation A61M1/3672
• CPC Class Codes: A61M 1/3441 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 1/3448 by mechanically linked pumps in both ultra-filtrate and substitution flow line
• CPC Class Codes: A61M 1/3458 having electrolytes not present in the dialysate
• CPC Class Codes: A61M 1/361 before treatment
• CPC Class Codes: A61M 1/3612 after treatment
• 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 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3646 Expelling the residual body fluid after use, e.g. back to the body
• CPC Class Codes: A61M 1/367 : Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/126 : with incorporated membrane filters
• CPC Class Codes: A61M 2205/128 : with incorporated valves
• CPC Class Codes: A61M 2205/15 : Detection of leaks
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/35 : Communication
• CPC Class Codes: A61M 2205/3553 : remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3569 : sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/60 : with identification means
• CPC Class Codes: A61M 2205/6018 : providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2205/6072 : Bar codes
• CPC Class Codes: A61M 39/0208 : Subcutaneous access sites for injecting or removing fluids transcutaneous access sites A61M39/0247; implantable infusion devices A61M5/14276

Abstract

Systems and methods balance fluid in a fluid processing procedure during which an outgoing fluid is removed from an individual and an ingoing fluid is supplied to the individual. The systems and methods supply a volume of the outgoing fluid and a volume of the ingoing fluid into a volumetric chamber. The systems and methods discharge a volume of the outgoing fluid and a volume of the ingoing fluid from the volumetric chamber. The systems and methods synchronizes the supply and discharge of fluid to affect a concurrent discharge of the outgoing fluid and ingoing fluid from the volumetric chamber in volumetric balance with a concurrent supply of outgoing fluid and ingoing fluid into the volumetric chamber. The volumetric chamber can include at least one chamber including an interior wall dividing the chamber into a first compartment and a second compartment. The first compartment retains a volume of outgoing fluid. The second compartment retains a volume of ingoing fluid. The interior wall responds to differential fluid pressure to discharge the ingoing fluid from the second compartment as the outgoing fluid is conveyed into the first compartment, and vice versa.

Claims

1. A fluid balancing system for use in a fluid processing procedure during which an outgoing fluid is removed from an individual and an ingoing fluid is supplied to the individual, the system comprising a volumetric chamber assembly, a first flow assembly communicating with the volumetric chamber assembly for supplying a volume of the outgoing fluid and a volume of the ingoing fluid into the volumetric chamber assembly, a second flow assembly communicating with the volumetric chamber assembly for discharging a volume of the outgoing fluid and a volume of the ingoing fluid from the volumetric chamber assembly, and a synchronization unit configured to mechanically couple and thereby drive the first and second flow assemblies to effect a concurrent discharge of the outgoing fluid and ingoing fluid from the volumetric chamber assembly in volumetric balance with a concurrent supply of outgoing fluid and ingoing fluid into the volumetric chamber assembly.

2. A system according to claim 1

wherein the volumetric chamber assembly is configured to be selectively placed in operative association with the first and second flow assemblies for use and selectively removed from operative association with the first and second flow assemblies after use.

3. A system according to claim 1

wherein the volumetric chamber assembly includes at least one chamber including an interior wall dividing the chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to discharge the ingoing fluid from the second compartment as the outgoing fluid is conveyed into the first compartment, and vice versa.

4. A system for volumetrically balancing the supply of ingoing fluid to an individual with the withdrawal of outgoing fluid from the individual comprising a first chamber and a second chamber, each including an interior wall dividing the respective chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to displace outgoing fluid from the first compartment as ingoing fluid is conveyed into the second compartment and vice versa, a first flow control assembly communicating with a source of outgoing fluid and the first compartments of the first and second chambers, a second flow control assembly communicating with a source of ingoing fluid and the second compartment of the first and second chambers, and a synchronization unit mechanically driving first and second flow control assemblies and operable in a first cycle, during which the first and second flow control assemblies convey a volume of outgoing fluid into the first compartment of the first chamber to displace a volume of ingoing fluid from the second compartment of the first chamber, while conveying ingoing fluid into the second compartment of the second chamber to displace a volume of outgoing fluid from the first compartment of the second chamber, the synchronization unit also being operable in a second cycle, during which the first and second flow control assemblies are driven to convey a volume of ingoing fluid into the second compartment of the first chamber to displace a volume of outgoing fluid from the first compartment of the first chamber, while conveying a volume of outgoing fluid into the first compartment of the second chamber to displace a volume of ingoing fluid from the second compartment of the second chamber, the synchronization unit operating during the first and second cycles to achieve a predetermined volumetric balance between outgoing fluid and ingoing fluid conveyed through the first and second chambers.

5. A system for volumetrically balancing the supply of ingoing fluid to an individual with the withdrawal of outgoing fluid from the individual comprising a first chamber and a second chamber, each including an interior wall dividing the respective chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to displace outgoing fluid from the first compartment as ingoing fluid is conveyed into the second compartment and vice versa, a first flow control assembly communicating with a source of outgoing fluid and the first compartments of the first and second chambers, a second flow control assembly communicating with a source of ingoing fluid and the second compartment of the first and second chambers, and a synchronization unit coupled to first and second flow control assemblies being operable in a first cycle, during which the first and second flow control assemblies are commanded to convey a volume of outgoing fluid into the first compartment of the first chamber to displace a volume of ingoing fluid from the second compartment of the first chamber, while conveying ingoing fluid into the second compartment of the second chamber to displace a volume of outgoing fluid from the first compartment of the second chamber, the synchronization unit also being operable in a second cycle, during which the first and second flow control assemblies are commanded to convey a volume of ingoing fluid into the second compartment of the first chamber to displace a volume of outgoing fluid from the first compartment of the first chamber, while conveying a volume of outgoing fluid into the first compartment of the second chamber to displace a volume of ingoing fluid from the second compartment of the second chamber, the synchronization unit operating during the first and second cycles to achieve a predetermined volumetric balance between outgoing fluid and ingoing fluid conveyed through the first and second chambers;

wherein the synchronization unit includes a drive assembly jointly coupled to the first and second flow control assemblies.

6. A system according to claim 5

wherein the drive assembly mechanically couples the first and second flow control assemblies together.

7. A system for volumetrically balancing the supply of ingoing fluid to an individual with the withdrawal of outgoing fluid from the individual comprising a first chamber and a second chamber, each including an interior wall dividing the respective chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to displace outgoing fluid from the first compartment as ingoing fluid is conveyed into the second compartment and vice versa, a first flow control assembly communicating with a source of outgoing fluid and the first compartments of the first and second chambers, a second flow control assembly communicating with a source of ingoing fluid and the second compartment of the first and second chambers, and a synchronization unit coupled to first and second flow control assemblies being operable in a first cycle, during which the first and second flow control assemblies are commanded to convey a volume of outgoing fluid into the first compartment of the first chamber to displace a volume of ingoing fluid from the second compartment of the first chamber, while conveying ingoing fluid into the second compartment of the second chamber to displace a volume of outgoing fluid from the first compartment of the second chamber, the synchronization unit also being operable in a second cycle, during which the first and second flow control assemblies are commanded to convey a volume of ingoing fluid into the second compartment of the first chamber to displace a volume of outgoing fluid from the first compartment of the first chamber, while conveying a volume of outgoing fluid into the first compartment of the second chamber to displace a volume of ingoing fluid from the second compartment of the second chamber, the synchronization unit operating during the first and second cycles to achieve a predetermined volumetric balance between outgoing fluid and ingoing fluid conveyed through the first and second chambers;

wherein the first flow control assembly includes a outgoing fluid inlet passage communicating jointly with the first compartments of the first and second chambers, and a first peristaltic pump unit operatively associated with the outgoing fluid inlet passage, wherein the second flow control assembly includes a ingoing fluid inlet passage communication jointly with the second compartments of the first and second chambers, and a second peristaltic pump unit operatively associated with the ingoing fluid inlet passage, and wherein the synchronization unit includes a drive assembly jointly coupled to the first and second peristaltic pump units.

8. A system according to claim 7

wherein the synchronization unit includes a member to meter flow in the outgoing fluid inlet passage in proportion to flow in the ingoing fluid inlet passage during operation of the first and second peristaltic pump units.

9. A system according to claim 8

wherein the member reduces fluid flow in the outgoing fluid inlet passage in proportion to fluid flow in the ingoing fluid inlet passage.

10. A system for volumetrically balancing the supply of ingoing fluid to an individual with the withdrawal of outgoing fluid from the individual comprising a first chamber and a second chamber, each including an interior wall dividing the respective chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to displace outgoing fluid from the first compartment as ingoing fluid is conveyed into the second compartment and vice versa, a first flow control assembly communicating with a source of outgoing fluid and the first compartments of the first and second chambers, a second flow control assembly communicating with a source of ingoing fluid and the second compartment of the first and second chambers, and a synchronization unit coupled to first and second flow control assemblies being operable in a first cycle, during which the first and second flow control assemblies are commanded to convey a volume of outgoing fluid into the first compartment of the first chamber to displace a volume of ingoing fluid from the second compartment of the first chamber, while conveying ingoing fluid into the second compartment of the second chamber to displace a volume of outgoing fluid from the first compartment of the second chamber, the synchronization unit also being operable in a second cycle, during which the first and second flow control assemblies are commanded to convey a volume of ingoing fluid into the second compartment of the first chamber to displace a volume of outgoing fluid from the first compartment of the first chamber, while conveying a volume of outgoing fluid into the first compartment of the second chamber to displace a volume of ingoing fluid from the second compartment of the second chamber, the synchronization unit operating during the first and second cycles to achieve a predetermined volumetric balance between outgoing fluid and ingoing fluid conveyed through the first and second chambers;

wherein the first flow control assembly includes a first inlet valve assembly controlling flow of outgoing fluid into the first compartments of the first and second chambers, and a first outlet valve assembly controlling flow of ingoing fluid from the second compartments of the first and second chambers, wherein the second flow control assembly includes a second inlet valve assembly controlling flow of ingoing fluid into the second compartments of the first and second chambers, and a second outlet valve assembly controlling flow of outgoing fluid from the first compartments of the first and second chambers, and wherein the synchronization unit includes a drive assembly jointly coupled to the first inlet valve assembly, the first outlet valve assembly, the second inlet valve assembly, and the second outlet valve assembly.

11. A system according to claim 10

wherein the drive assembly mechanically links the first inlet valve assembly, the first outlet valve assembly, the second inlet valve assembly, and the second outlet valve assembly together.

12. A system according to claim 10

wherein the first flow control assembly includes a first pump to convey outgoing fluid to the first inlet valve assembly, and

wherein the synchronization unit couples the drive assembly to the first pump.

13. A system according to claim 12

wherein the drive assembly is mechanically linked to the first pump.

14. A system according to claim 12

wherein the drive assembly ratiometrically links the first pump to the first inlet valve assembly, the first outlet valve assembly, the second inlet valve assembly, and the second outlet valve assembly.

15. A system according to claim 10

wherein the second flow control assembly includes a second pump to convey ingoing fluid to the second inlet valve assembly, and

wherein the synchronization unit couples the drive assembly to the second pump.

16. A system according to claim 15

wherein the common drive assembly is mechanically linked to the second pump.

17. A system according to claim 15

wherein the common drive assembly ratiometrically links the second pump to the first inlet valve assembly, the first outlet valve assembly, the second inlet valve assembly, and the second outlet valve assembly.

18. A system according to claim 10

wherein the first flow control assembly includes a first pump to convey outgoing fluid to the first inlet valve assembly,

wherein the second flow control assembly includes a second pump to convey ingoing fluid to the second inlet valve assembly, and

wherein the synchronization unit couples the drive assembly to the first pump and the second pump.

19. A system according to claim 18

wherein the drive assembly is mechanically linked to the first pump and the second pump.

20. A system according to claim 18

wherein the common drive assembly ratiometrically links the first pump and second pump to the first inlet valve assembly, the first outlet valve assembly, the second inlet valve assembly, and the second outlet valve assembly.

21. A fluid handling system comprising

a chamber including an interior wall dividing the chamber into a first compartment to retain a volume of a first fluid and a second compartment to retain a volume of a second fluid, the interior wall responding to differential fluid pressure to discharge the second fluid from the second compartment as the first fluid is conveyed into the first compartment,

a flow control assembly comprising an inlet valve controlling flow of the first fluid into the first compartment, an outlet valve controlling flow of the second fluid from the second compartment, and a pump to convey the first fluid from a source into the first compartment through the inlet valve, and

a synchronization unit coupled to the flow control assembly to volumetrically balance flow of the first fluid into the first compartment and discharge of the second fluid from the second compartment, the synchronization unit including a drive assembly that mechanically links together the inlet valve, the outlet valve, and the pump.

22. A system according to claim 21

wherein the drive assembly ratiometrically links the inlet valve and the outlet valve to the pump, whereby changes in pump speed proportionally changes operation of the inlet valve and outlet valve.

23. A system according to claim 21

wherein the pump includes a peristaltic pump having a drive motor.

24. A fluid handling system comprising a chamber including an interior wall dividing the chamber into a first compartment to retain a volume of a first fluid and a second compartment to retain a volume of a second fluid, the interior wall responding to differential fluid pressure to discharge the second fluid from the second compartment as the first fluid is conveyed into the first compartment, a flow control assembly comprising an inlet valve controlling flow of the first fluid into the first compartment, an outlet valve controlling flow of the second fluid from the second compartment, and a pump to convey the first fluid from a source into the first compartment through the inlet valve, and a synchronization unit coupled to the flow control assembly to volumetrically balance flow of the first fluid into the first compartment and discharge of the second fluid from the second compartment, the synchronization unit including a drive assembly that mechanically links together the inlet valve, the outlet valve, and the pump;

wherein the pump includes a peristaltic pump having a drive motor

wherein the synchronization unit includes a cam drive assembly linked to the drive motor that operates the inlet valve and the outlet valve.

25. A fluid handling system comprising a chamber having an interior volume and including an interior wall dividing the chamber into a first compartment to retain a volume of a first fluid and a second compartment to retain a volume of a second fluid, the interior wall responding to differential fluid pressure to discharge the second fluid from the second compartment as the first fluid is conveyed into the first compartment, a flow control assembly comprising an inlet valve controlling flow of the first fluid into the first compartment, an outlet valve controlling flow of the second fluid from the second compartment, and a pump to convey the first fluid from a source into the first compartment through the inlet valve, and a synchronization unit coupled to the flow control assembly to volumetrically balance flow of the first fluid into the first compartment and discharge of the second fluid from the second compartment, the synchronization unit mechanically synchronizing the inlet and outlet valves with the pump such that the volume of the second fluid discharged is less than the interior volume of the chamber.

26. A system according to claim 25

wherein the pump includes a peristaltic pump having a drive motor.

27. A fluid handling system comprising a chamber having an interior volume and including an interior wall dividing the chamber into a first compartment to retain a volume of a first fluid and a second compartment to retain a volume of a second fluid, the interior wall responding to differential fluid pressure to discharge the second fluid from the second compartment as the first fluid is conveyed into the first compartment, a flow control assembly comprising an inlet valve controlling flow of the first fluid into the first compartment, an outlet valve controlling flow of the second fluid from the second compartment, and a pump to convey the first fluid from a source into the first compartment through the inlet valve, and a synchronization unit coupled to the flow control assembly to volumetrically balance flow of the first fluid into the first compartment and discharge of the second fluid from the second compartment, the synchronization unit synchronizing the inlet and outlet valves with the pump such that the volume of the second fluid discharged is less than the interior volume of the chamber;

wherein the synchronization unit includes a drive assembly jointly coupled to the inlet valve, the outlet valve, and the pump.

28. A system according to claim 27

wherein the drive assembly mechanically links together the inlet valve, the outlet valve, and the pump.

29. A system according to claim 27

wherein the drive assembly ratiometrically links the inlet valve and the outlet valve to the pump, whereby changes in pump speed proportionally changes operation of the inlet valve and outlet valve.

30. A fluid balancing system for use in a fluid processing procedure during which an outgoing fluid is removed from an individual and an ingoing fluid is supplied to the individual, the system comprising:

volumetric chamber assembly;

a first flow assembly communicating with the volumetric chamber assembly for supplying a volume of the outgoing fluid and a volume of the ingoing fluid into the volumetric chamber assembly;

a second flow assembly communicating with the volumetric chamber assembly for discharging a volume of the outgoing fluid and a volume of the ingoing fluid from the volumetric chamber assembly; and

a synchronization unit driving the first and second flow assemblies causing concurrent discharge of the outgoing fluid and ingoing fluid from the volumetric chamber assembly in volumetric balance with a concurrent supply of outgoing fluid and ingoing fluid into the volumetric chamber assembly.

31. A system as in claim 30, wherein:

said first and second flow assemblies include valves controlling flow into and out of said volumetric chamber assembly; and

said valves are operated by said synchronization unit.

32. A system as in claim 31, wherein:

said first and second flow assemblies include pumps also operated by said synchronization unit.

33. A system as in claim 32, wherein said pumps and said valves are mechanically coupled and driven by a common drive to achieve synchronization thereof.

34. A system as in claim 30, wherein:

said first and second flow assemblies include pumps also operated by said synchronization unit.

35. A fluid balancing system for use in a fluid processing procedure during which an outgoing fluid is removed from an individual and an ingoing fluid is supplied to the individual, the system comprising a volumetric chamber assembly, a first flow assembly communicating with the volumetric chamber assembly for supplying a volume of the outgoing fluid and a volume of the ingoing fluid into the volumetric chamber assembly, a second flow assembly communicating with the volumetric chamber assembly for discharging a volume of the outgoing fluid and a volume of the ingoing fluid from the volumetric chamber assembly, and a synchronization unit configured to mechanically couple and thereby drive the first and second flow assemblies to effect a concurrent discharge of the outgoing fluid and ingoing fluid from the volumetric chamber assembly in volumetric balance with a concurrent supply of outgoing fluid and ingoing fluid into the volumetric chamber assembly;

wherein the volumetric chamber assembly is configured to be selectively placed in operative association with the first and second flow assemblies for use and selectively removed from operative association with the first and second flow assemblies after use.

36. A fluid balancing system for use with a patient treatment process in which an outgoing fluid is removed from a patient and an ingoing fluid is supplied to the patient, comprising:

at least one first disposable volumetric chamber connectable to a filter to receive waste fluid from said filter and eject said waste fluid into a waste flow line;

at least one second disposable volumetric chamber connected to draw from a supply of replacement fluid and eject into a replacement fluid line for supply to a patient;

a synchronization unit including and operating at least one inlet valve, at least one outlet valve, at least one replacement fluid pump and at least one waste fluid pump synchronously, said synchronization unit being operatively associated with said at least one first volumetric chamber and said at least one second disposable volumetric chamber such that waste fluid received by said first volumetric chamber displaces replacement fluid in said second volumetric chamber, thereby determining a rate at which said replacement fluid is ejected from said second pumping section;

said synchronization unit being configured such that replacement fluid is delivered continuously during a blood treatment without halting to empty said at least one second disposable pumping chamber.

37. A system as in claim 36, wherein:

said at least one first volumetric chamber includes two first volumetric chambers and said at least one second volumetric chamber includes two second volumetric chambers; and

said synchronization unit is configured to empty a first of said two first volumetric chambers while filling a second of said two first volumetric chambers.

38. A system as in claim 37, wherein said synchronization unit is configured to drive said at least one inlet valve and said at least one outlet valve in a synchronous fashion such that said first of said two first volumetric chambers presses directly against a first of said two second volumetric chambers as said first two volumetric chambers fill.

39. A system as in claim 38, further comprising a common fixed volume that surrounds said first of said two first volumetric chambers and said first of said two second volumetric chambers such that first of said two first volumetric chambers press directly against said first of said two second volumetric chambers.

40. A fluid balancing system for use with a patient treatment process in which an outgoing fluid is removed from a patient and an ingoing fluid is supplied to the patient, comprising:

first and second fluid circuits each with waste and replacement fluid volumetric chambers connected hermetically to respective connectors for waste fluid withdrawal from a waste fluid source and waste fluid disposal and for replacement fluid withdrawal from a supply and infusion to a patient;

a mechanical synchronization unit including at least one pump;

said first and second fluid circuit waste and replacement fluid volumetric chambers each having flexible walls;

valves controlling flow of fluid into and out of said volumetric chambers;

said synchronization unit being configured to operate said valves such that during a first cycle, waste fluid filling said first fluid circuit waste volumetric chamber displaces replacement fluid in said first fluid circuit replacement fluid volumetric chamber as replacement fluid filling said second fluid, circuit replacement fluid volumetric chamber displaces waste fluid in said second fluid circuit waste volumetric chamber and during a second cycle waste fluid filling said second fluid circuit waste volumetric chamber displaces replacement fluid in said second fluid circuit replacement fluid volumetric chamber as replacement fluid filling said first fluid circuit replacement fluid volumetric chamber displaces waste fluid in said first fluid circuit waste volumetric chamber.

41. A system as in claim 40, wherein said first and second fluid circuits overlap such that two layers separate interiors of respective ones of said one of said replacement fluid and waste volumetric chambers.

42. A system as in claim 40, further comprising a chassis supporting said volumetric chambers.

43. A fluid balancing system for use with a patient treatment process in which an outgoing fluid is removed from a patient and an ingoing fluid is supplied to the patient, comprising:

a disposable fluid circuit including flexible wall portions defining at least one waste fluid chamber and at least one replacement fluid chamber;

a drive mechanism including a pump engageable with said fluid circuit such that waste fluid may be pumped into said at least one waste fluid chamber;

said drive mechanism operating valves synchronously such that replacement fluid is extracted from said at least one replacement fluid chamber in equal volume increments as said at least one waste fluid chamber is filled;

said drive mechanism being configurable to engage said disposable fluid circuit and reconfigurable for conducting said patient treatment process.

44. A system as in claim 43, wherein said drive mechanism includes a pair of recesses that enclose said at least one waste fluid chamber and said at least one replacement fluid chamber to define a fixed volume when said drive mechanism is configured to engage said disposable fluid circuit, whereby fluid filling said waste fluid chamber directly displaces fluid in said replacement fluid chamber.

45. A fluid balancing system for use with a patient treatment process in which an outgoing fluid is removed from a patient and an ingoing fluid is supplied to the patient, comprising:

a fluid circuit with volumetric chambers;

a blood treatment device with a motor, pumps, and valves operatively associated with said fluid circuit and configured such that said pumps and valves are synchronously driven by said motor;

said fluid circuit being removable from said blood treatment device.

46. A system as in claim 45, wherein said blood treatment device includes cams to drive said valves.

47. A system as in claim 45, wherein said at least one pump includes a replacement fluid pump and a waste fluid pump, each mechanically coupled to synchronize them with said at least one valve.

48. A system as in claim 45, wherein said at least one valve includes inlet and outlet valves respective to said at least one of said volumetric chambers and inlet and outlet valves respective to said at least another of said volumetric chambers.

49. A system as in claim 45, wherein said blood treatment device includes a cam mechanism to operate said at least one valve.

50. A fluid balancing system for use with a patient treatment process in which a waste fluid is removed from said patient and a replacement fluid is supplied to the patient, comprising:

a fluid circuit with volumetric chambers;

a blood treatment device with a motor, at least one pump, and at least one valve operatively associated with said fluid circuit and configured such that said at least one pump and said at least one valve are synchronously driven by said motor such that said waste fluid is moved into at least one of said volumetric chambers displacing replacement fluid in at least another of said volumetric chambers;

said fluid circuit being removable from said blood treatment device.

51. A system as in claim 50, wherein said blood treatment device includes a cam mechanism to operate said respective inlet and outlet valves.

52. A system for volumetrically balancing the supply of ingoing fluid to an individual with the withdrawal of outgoing fluid from the individual comprising a first chamber and a second chamber, each including an interior wall dividing the respective chamber into a first compartment to retain a volume of outgoing fluid and a second compartment to retain a volume of ingoing fluid, the interior wall responding to differential fluid pressure to displace outgoing fluid from the first compartment as ingoing fluid is conveyed into the second compartment and vice versa, a first flow control assembly communicating with a source of outgoing fluid and the first compartments of the first and second chambers, a second flow control assembly communicating with a source of ingoing fluid and the second compartment of the first and second chambers, and a synchronization unit coupled to first and second flow control assemblies being operable in a first cycle, during which the first and second flow control assemblies are commanded to convey a volume of outgoing fluid into the first compartment of the first chamber to displace a volume of ingoing fluid from the second compartment of the first chamber, while conveying ingoing fluid into the second compartment of the second chamber to displace a volume of outgoing fluid from the first compartment of the second chamber, the synchronization unit also being operable in a second cycle, during which the first and second flow control assemblies are commanded to convey a volume of ingoing fluid into the second compartment of the first chamber to displace a volume of outgoing fluid from the first compartment of the first chamber, while conveying a volume of outgoing fluid into the first compartment of the second chamber to displace a volume of ingoing fluid from the second compartment of the second chamber, the synchronization unit operating during the first and second cycles to achieve a predetermined volumetric balance between outgoing fluid and ingoing fluid conveyed through the first and second chambers;

wherein the synchronization unit is operable in a transition cycle between the first and second cycles, and wherein, during the transition cycle, the synchronization unit operates the first and second flow control assemblies to prevent flow of both outgoing and ingoing fluids into the respective first and second compartments.

53. A fluid balancing system for use with a patient treatment process in which an waste fluid is removed from a patient and an replacement fluid is supplied to the patient, comprising:

a fluid circuit with volumetric chambers;

a blood treatment device with a replacement fluid pump, a waste fluid pump, and a motor;

said blood treatment machine including valves operatively associated with said fluid circuit;

said blood treatment machine being configured such that said replacement fluid pump and said waste fluid pump are mechanically interlocked, such that said waste fluid is moved into at least one of said volumetric chambers displacing replacement fluid in at least another of said volumetric chambers, and driven synchronously by said motor;

said fluid circuit being removable from said blood treatment device.