Recirculating dialysate fluid circuit for blood measurement

• US 10,583,236 B2
• Filed: 01/04/2017
• Issued: 03/10/2020
• Est. Priority Date: 01/09/2013
• Status: Active Grant

• Current Assignee: Mozarc Medical US LLC
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Pudil, Bryant J., Meyer, Thomas E., Lura, David B., Gerber, Martin T.
• Primary Examiner(s): Kim, John
• Application Number:
  US15/398,069
• Publication Number:
  US 20170112991A1
• Time in Patent Office: 1,161 Days
• 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 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1609 after use, i.e. downstream of dialyser
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1619 Sampled collection of used dialysate, i.e. obviating the need for recovery of whole dialysate quantity for post-dialysis analysis
• CPC Class Codes: A61M 1/165 with a dialyser bypass on the dialysis fluid line
• CPC Class Codes: A61M 1/1694 with recirculating dialysing liquid
• 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 1/3406 Physical characteristics of the filtrate, e.g. urea
• 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 2202/0498 Urea
• CPC Class Codes: A61M 2205/05 combined with other kinds of therapy
• CPC Class Codes: A61M 2205/15 Detection of leaks
• 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 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: B01D 15/08 Selective adsorption, e.g. chromatography
• CPC Class Codes: B01D 15/362 Cation-exchange

Abstract

A blood based solute monitoring system for measuring at least one blood solute species that has a first recirculation flow path in fluid communication with a dialyzer. The first recirculation flow path is configured to allow a fluid to recirculate through a dialyzer such that the concentration of at least one solute species in the fluid becomes equilibrated to the solute species concentration of the blood in a blood compartment of the dialyzer. The blood solute monitoring system has at least one sensor to measure a fluid characteristic.

Claims

1. A method for determining an effective clearance of a dialyzer, comprising:

measuring a first conductivity value of a dialysate flowing from an outlet of the dialyzer not having contacted a urease containing material layer of a sorbent regeneration system;

measuring a second conductivity value of the dialysate flowing from the outlet of the dialyzer after the dialysate has contacted the urease containing material layer of the sorbent regeneration system;

intermittently providing an electrolyte bolus or diluent to a dialysate flow path and measuring a bolus conductivity of the dialysate passing to the dialyzer to provide a third conductivity value;

measuring a bolus conductivity of the dialysate passing from the dialyzer to provide a fourth conductivity value;

measuring a dialysate flow rate; and

determining the effective clearance of the dialyzer from the third and fourth conductivity values.

2. The method of claim 1, further comprising:

determining a BUN (blood urea nitrogen) and/or a blood concentration of a solute from the effective clearance of the dialyzer from the first and second conductivity values.

3. The method of claim 1, further comprising the step of determining a urea content of the dialysate flowing from the dialyzer based at least in part on a difference in conductivity between the first and second conductivity values.

4. The method of claim 1, wherein the dialysate contacts a plurality of materials of the sorbent regeneration system in a sequential order;

wherein the plurality of materials are contained in one or more sorbent cartridges, and wherein at least one material includes an ion exchange resin selective for calcium ions and magnesium ions and releasing hydrogen ions in exchange.

5. The method of claim 1, further comprising:

determining a third conductivity value of the equilibrated dialysate that has contacted an additional material layer other than the material layer(s) contacted by the dialysate of the first or second conductivity value; and

determining a blood solute concentration of at least a second blood solute from either the second and third conductivity values or the first and third conductivity values.

6. The method of claim 1, further comprising calculating one or more of the selected measures:

URR (urea reduction ratio), Kt/V, eKt/V (equilibrated Kt/V), and PCR (protein catabolic rate), wherein K stands for dialyzer clearance rate, t stands for dialysis time, and V stands for volume of distribution of urea; and

wherein Kt/V, eKt/V and PCR are each determined based on a difference between the first and second conductivity values; and

wherein URR is determined by calculating a first BUN (blood urea nitrogen) prior to dialysis and a second BUN (blood urea nitrogen) post dialysis.