Fluid balancing systems and methods

• US 9,115,708 B2
• Filed: 04/25/2014
• Issued: 08/25/2015
• Est. Priority Date: 02/27/2007
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: van der Merwe, Dirk A., Wilt, Michael J.
• Primary Examiner(s): Kim, John
• Application Number:
  US14/262,178
• Publication Number:
  US 20140322053A1
• Time in Patent Office: 487 Days
• US Class Current: 1/1
• CPC Class Codes: A61M 1/1524 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• 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 1/156 Constructional details of the cassette, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/15625 the reservoirs acting as balance chambers
• 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 1/1613 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 1/341 by measuring the filtrate rate or volume
• 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 1/3465 using dialysate as substitution fluid
• CPC Class Codes: A61M 1/3609 Physical characteristics of the blood, e.g. haematocrit, urea
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• 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 1/362265 : Details of valves
• CPC Class Codes: A61M 1/362266 : Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3623 : Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3646 : Expelling the residual body fluid after use, e.g. back to the body
• 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 2202/0413 : Blood
• CPC Class Codes: A61M 2205/12 : with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/18 : with alarm
• 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 2205/3331 : 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 2205/502 : User interfaces, e.g. screens or keyboards
• CPC Class Codes: F04B 45/0536 : the actuating fluid being controlled by one or more valves
• CPC Class Codes: G16H 20/40 : relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/63 : for local operation

Abstract

Hemodialysis dialysis systems are disclosed. Hemodialysis systems of the invention may include a dialysate flow path including a balancing circuit, a mixing circuit, and/or a directing circuit. The circuits may be defined within one or more cassettes. The fluid circuits may be at least partially isolated, spatially and/or thermally, from electrical components of the system. A gas supply may be provided in fluid communication with the dialysate flow path and/or the dialyzer to, urge dialysate through the dialyzer and blood back to the patient. The hemodialysis systems may include fluid handling devices actuated using a control fluid, optionally delivered using detachable pump. Fluid handling devices may be generally rigid and of a spheroid shape, optionally with a diaphragm dividing the device into compartments.

Claims

1. A cassette-based fluid balancing system, comprising:

a first liquid flow path connecting a first inlet to a first outlet;

a second liquid flow path connecting a second inlet to a second outlet;

a control fluid path configured for controlling a diaphragm pump;

said pump comprising a rigid vessel containing a diaphragm dividing the rigid vessel into a control compartment and a liquid pumping compartment, the control compartment of said pump being in fluidic communication with the control fluid path and the liquid pumping compartment being in fluidic communication with the second liquid flow path;

a balancing chamber comprising a flexible diaphragm dividing the chamber into two liquid compartments, a first liquid compartment in fluidic communication with the first liquid flow path and a second liquid compartment in fluidic communication with the second liquid flow path;

the balancing chamber configured to balance flow between the first liquid flow path and the second liquid flow path; and

a first valve interposed between the liquid pumping compartment of the diaphragm pump and the second liquid compartment of the balancing chamber, said first valve under control of a controller;

wherein

the controller is configured to operate the first valve using pulse-width modulation.

2. The system of claim 1, further comprising a second valve interposed between the second liquid compartment of the balancing chamber and the second outlet, wherein the controller is configured to operate the second valve so that it is closed while the first valve is operated using pulse-width modulation.

3. The system of claim 2, wherein while the second valve is closed, the controller operates the first valve using pulse-width modulation in a manner to provide a lower or more controlled pressure to the second liquid in the second liquid flow path as the first valve is being closed.

4. The system of claim 2, further comprising a third valve interposed between the first liquid compartment of the balancing chamber and the first inlet, wherein said first, second and third valves comprise membrane valves actuated by a control fluid, and wherein said second and third valves share a common control fluid line, causing said second and third valves to be opened together or closed together simultaneously.

5. A cassette-based fluid balancing system, comprising:

a first liquid flow path connecting a first inlet to a first outlet;

a second liquid flow path connecting a second inlet to a second outlet;

a control fluid path configured for controlling a diaphragm pump;

said pump comprising a rigid vessel containing a diaphragm dividing the rigid vessel into a control compartment and a liquid pumping compartment, the control compartment of said pump being in fluidic communication with the control fluid path and the liquid pumping compartment being in fluidic communication with the second liquid flow path;

a balancing chamber comprising a rigid chamber with a flexible diaphragm dividing the chamber into two liquid compartments, a first liquid compartment in fluidic communication with the first liquid flow path and a second liquid compartment in fluidic communication with the second liquid flow path;

the balancing chamber configured to balance flow between the first liquid flow path and the second liquid flow path; and

a first membrane valve interposed between the liquid pumping compartment of the diaphragm pump and the second liquid compartment of the balancing chamber, said first membrane valve under control of a control system comprising at least one controller;

wherein

the control system is configured to control application of a closing pressure to the first membrane valve so that pressure applied during closure of the first membrane valve is less than pressure applied to maintain the first membrane valve closed, and to control operation of the fluid balancing system so that the balancing chamber balances flow between the first liquid flow path and the second liquid flow path by displacing a volume of a first liquid in the first liquid compartment as a substantially equal volume of a second liquid is pumped into the second liquid compartment.

6. The system of claim 5, further comprising a second membrane valve interposed between the second liquid compartment of the balancing chamber and the second outlet, wherein the control system is configured to operate the second membrane valve so that it is maintained in a closed position while the first membrane valve is being closed.

7. The system of claim 6, wherein while pressure is applied to the second membrane valve to maintain it in a closed position, the control system operates the first membrane valve in a manner to apply a lower pressure or a more controlled pressure increase to the first membrane valve as it is being closed than the pressure being applied to the second membrane valve.

8. The system of claim 6, further comprising a third membrane valve interposed between the first liquid compartment of the balancing chamber and the first inlet, wherein said first, second and third membrane valves are actuated by a control fluid, and wherein said second and third membrane valves share a common control fluid line, causing said second and third membrane valves to be opened together or closed together simultaneously.

9. A cassette-based fluid balancing system for a hemodialysis apparatus, comprising:

a first dialysate flow path connecting a first inlet to a first outlet;

a second dialysate flow path connecting a second inlet to a second outlet;

a control fluid path configured for controlling a diaphragm pump;

said pump comprising a rigid vessel containing a diaphragm dividing the rigid vessel into a control compartment and a dialysate pumping compartment, the control compartment of said pump being in fluidic communication with the control fluid path and the dialysate pumping compartment being in fluidic communication with the second dialysate flow path;

a balancing chamber comprising a rigid chamber with a flexible diaphragm dividing the chamber into two dialysate compartments, a first dialysate compartment in fluidic communication with the first dialysate flow path and a second dialysate compartment in fluidic communication with the second dialysate flow path;

the balancing chamber configured to balance flow between the first dialysate flow path and the second dialysate flow path; and

a first membrane valve interposed between the dialysate pumping compartment of the diaphragm pump and the second dialysate compartment of the balancing chamber, said first membrane valve under control of a control system comprising at least one controller;

wherein

the control system is configured to control application of a closing pressure to the first membrane valve so that pressure applied during closure of the first membrane valve is less than pressure applied to maintain the first membrane valve closed, and to control operation of the fluid balancing system so that the balancing chamber balances flow between the first dialysate flow path and the second dialysate flow path by displacing a volume of a first dialysate in the first dialysate compartment as a substantially equal volume of a second dialysate is pumped into the second dialysate compartment.

10. The system of claim 9, further comprising a second membrane valve interposed between the second dialysate compartment of the balancing chamber and the second outlet, wherein the control system is configured to operate the second membrane valve so that it is maintained in a closed position while the first membrane valve is being closed.

11. The system of claim 10, wherein while pressure is applied to the second membrane valve to maintain it in a closed position, the control system operates the first membrane valve in a manner to apply a lower pressure or a more controlled pressure increase to the first membrane valve as it is being closed than the pressure being applied to the second membrane valve.

12. The system of claim 10, further comprising a third membrane valve interposed between the first dialysate compartment of the balancing chamber and the first inlet, wherein said first, second and third membrane valves are actuated by a control fluid, and wherein said second and third membrane valves share a common control fluid line, causing said second and third membrane valves to be opened together or closed together simultaneously.