Dialyzer clearance check system

• US 5,110,477 A
• Filed: 02/13/1990
• Issued: 05/05/1992
• Est. Priority Date: 02/13/1990
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Howard, David B., Vishnoi, Rohit, Keshaviah, Prakash, Kenley, Rodney, Berry, Dennis
• Primary Examiner(s): Sever, Frank
• Application Number:
  US07/479,504
• Time in Patent Office: 812 Days
• Field of Search: 210/636, 210/634, 210/637, 210/644, 210/645, 210/646, 210/647, 210/649-652, 210/321.62, 210/321.6, 210/321.65, 210/321.71, 128/898, 422/48, 435/2, 435/1
• US Class Current: 210/647
• CPC Class Codes: A61M 1/16 with membranes
• 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 1/1615 using measurements made at different flow rates
• CPC Class Codes: A61M 2202/0498 Urea
• 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: B01D 61/32 Controlling or regulating
• CPC Class Codes: B01D 65/10 Testing of membranes or membrane apparatus; Detecting or repairing leaks

Abstract

A method for determining the clearance competency of dialyzers utilized in renal hemodialysis comprises measuring the conductivity of a dialysate solution of low initial conductivity while circulating a priming solution of greater conductivity on the blood side of the dialyzer, correlating the rate of dialysis of molecules contained in the printing solution to known clearance rates for urea or other targeted blood impurity for the types and compositions of the particular dialysis membranes being utilized, and calculating the precise length of treatment time or other treatment parameters required to cleanse the blood to be dialyzed of impurities and biotoxins to a predicted target value. Failsafe control means which prevents mistakes in connecting unsafe fluid sources to the dialyzer is also provided.

Claims

1. A method comprising determining clearance competency of hemodialyzers comprising:

a) contacting the blood side of a dialyzer membrane with a priming fluid;

b) simultaneously contacting the dialysate side of a dialyzer membrane with a diffusion fluid;

c) measuring the changes in solute level on either side of the said membrane with means for measuring; and

d) correlating the changes in solute level to a corresponding standard reference substance clearance value with means for correlating.

2. The method of claim 1 together with the further step of verifying the presence of dialysate in the dialysate chamber prior to commencement of hemodialysis.

3. The method of claim 1 wherein said solute is a molecule having substantially the same diffusion properties as a selected standard reference substance.

4. The method of claim 1 wherein said solute is a solution of sodium chloride.

5. The method of claim 1 wherein said diffusion fluid is water.

6. The method of claim 1 wherein said standard reference substance is urea.

7. A method comprising determining clearance competency of hemodialyzers comprising:

a) circulating a priming fluid containing a solute through the blood side of a dialyzer;

b) circulating simultaneously a diffusion fluid containing a lower level of said solute through the dialysate chamber on said dialyzer;

c) measuring the level of said solute in the diffusion fluid after the levels of said solute in the two fluids have come to equilibrium with means for measuring; and

d) correlating the level of said solute to a corresponding standard reference substance clearance value with means for correlating.

8. A method comprising determining clearance competency of hemodialyzers comprising:

a) circulating a priming fluid containing a solute through the blood side of a dialyzer;

b) circulating simultaneously a diffusion fluid containing a lower level of such solute through the dialysate chamber on said dialyzer;

c) measuring the solute concentration at unit time to obtain a rate value extrapolatable to the final solute level at equilibrium with means for measuring; and

d) correlating the final solute level to a corresponding standard reference substance clearance value with means for correlating.

9. A method comprising determining clearance competency of hemodialyzers comprising:

a) circulating a priming fluid containing a solute in a loop through the blood side of a dialyzer;

b) circulating simultaneously a diffusion fluid containing a lower level of such solute through the dialysate chamber on said dialyzer;

c) measuring the level of solute in the diffusion fluid successively to determine the rate at which the concentration of solute diminishes with means for measuring; and

d) correlating the rate of change in the solute level to a standard reference substance clearance value with means for correlating.

10. Apparatus for use during hemodialysis treatment with a dialyzer having a blood circulation pathway on one side of a semipermeable membrane and a dialysate chamber on the other side of said membrane, said apparatus comprising means for determining clearance competency of hemodialyzers including:

a) measuring means for measuring the composition of a dialyzing solution;

b) control means for activating a blood displacing pump to circulate blood through the dialyzer;

c) a detecting means connected to said control means for distinguishing between a priming solution and blood; and

d) interfacing means connecting the control means to the blood displacing pump for disabling the blood displacing pump when dialyzing solution is not present in the dialysate chamber.

11. The apparatus of claim 10 wherein said measuring means is a conductivity meter.