Hemodialysis systems and methods

• US 8,357,298 B2
• Filed: 08/27/2008
• Issued: 01/22/2013
• Est. Priority Date: 02/27/2007
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Demers, Jason A., Wilt, Michael J., Ballantyne, Todd A., Grant, Kevin L., Dale, James D.
• Primary Examiner(s): Fortuna, Jose A
• Application Number:
  US12/199,452
• Publication Number:
  US 20090095679A1
• Time in Patent Office: 1,609 Days
• Field of Search: 210645-646, 210/650, 210/767, 210/321.6, 210/96.2, 210/663, 604/4.01, 604/6.11, 604/5.04, 604/6.09
• US Class Current: 210/646
• 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 a 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 method of using a hemodialysis system, the hemodialysis system comprising:

a blood flow path;

a dialysate flow path;

a blood pump fluidically connected to the blood flow path and configured to draw blood from a patient and pump the blood through a dialyzer comprising a blood side fluidically connected to the blood flow path and a dialysate side fluidically connected to the dialysate flow path, wherein the blood side is separated from the dialysate side by a dialyzer membrane;

the dialysate flow path comprising;

a balancing circuit which controls the amount of dialysate passing through the dialyzer,

a mixing circuit which forms dialysate from constituents including water, and

a directing circuit which passes water from a water supply to the mixing circuit and passes dialysate from the mixing circuit to the balancing circuit; and

a reciprocating membrane based dialysate pump forming part of the balancing circuit and fluidically connected to the dialysate flow path, the dialysate pump being configured to pump dialysate through the dialyzer;

the method comprising steps of;

measuring a blood-side related pressure indicative of a pressure of blood in the blood side of the dialyzer;

measuring a dialysate-side related pressure indicative of a pressure of dialysate in the dialysate side of the dialyzer; and

operating the dialysate pump to pass dialysate through the dialyzer and to cause fluid to flow across the dialyzer membrane into the blood flow path when the measured blood-side related pressure is less than the measured dialysate-side related pressure and fluid to flow from the blood flow path across the dialyzer membrane into the dialysate flow path when the measured blood-side related pressure is greater than the measured dialysate-side related pressure.

2. The method of claim 1, wherein the blood flow path is defined by a blood flow cassette.

3. The method of claim 2, wherein the blood flow cassette comprises one or more reciprocating membrane-based pumps.

4. The method of claim 3, wherein the blood flow cassette comprises two reciprocating membrane-based pumps.

5. The method of claim 3, wherein the method comprises operating the dialysate pump to provide a fluid delivery stroke during a delivery stroke of the blood pump.

6. The method of claim 5, wherein the method comprises halting the dialysate pump when the blood pump is not providing a delivery stroke.

7. The method of claim 1, wherein the dialysate flow path is defined by at least one cassette.

8. The method of claim 1, wherein the balancing circuit of the dialysate flow path comprises first and second membrane-based dialysate pumps, and the method comprises:

passing dialysate through the dialyzer to cause fluid to flow from the first dialysate pump across the dialyzer membrane into the blood flow path during a delivery stroke of the first dialysate pump and to cause fluid to flow from the blood flow path across the dialyzer membrane into the dialysate flow path during a fill stroke of the second dialysate pump.

9. The method of claim 1, wherein the balancing circuit comprises a balancing pod that includes a fresh dialysate compartment separated from a spent dialysate compartment by a flexible membrane, the dialysate pump being configured to deliver spent dialysate to the balancing pod, displacing a volume of fresh dialysate from the balancing pod into the dialyzer, and the method comprises:

operating the dialysate pump to pass dialysate through the dialyzer such that fluid flows from the dialysate pump to the balancing pod during a delivery stroke to displace fresh dialysate from the balancing pod and cause it to pass across the dialyzer membrane into the blood flow path.