System and method for dialyzer evaluation

Patent metadata

Field	Value
Publication number	US-10625011-B2
Application number	US-201715720642-A
Country	US
Kind code	B2
Filing date	Sep 29, 2017
Priority date	Sep 29, 2017
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

Embodiments of the disclosure provide a method for evaluating dialyzers used in different medical applications (e.g., hemodialysis). Red blood cell volume lost in a dialyzer is monitored by obtaining blood flowrate measurements and hematocrit measurements at input ports and output ports of the dialyzer. The flowrate and hematocrit measurements are used to determine an accumulation of red cell blood volume in the dialyzer. The measurements may be obtained in a lab environment with an in-vitro blood source or may be obtained in a clinical setting with an in-vivo blood source from a patient.

First claim

The invention claimed is:

1. A method for evaluating a dialyzer using a dialyzer test system connected to the dialyzer, the method comprising:
circulating, using a pump of the dialyzer test system, blood from a blood source through the dialyzer; and
determining, using the dialyzer test system, a red blood cell volume loss corresponding to the dialyzer, wherein determining the red blood cell volume loss corresponding to the dialyzer includes:
(a) determining a blood flowrate corresponding to an input side of the dialyzer via a calibrated pumping rate of the pump or an input flowmeter of the dialyzer test system;
(b) determining a hematocrit value corresponding to the input side of the dialyzer via a first sensor assembly of the dialyzer test system attached to a first blood chamber of the dialyzer test system, wherein the first sensor assembly and the first blood chamber are disposed on the input side of the dialyzer;
(c) determining a blood flowrate corresponding to an output side of the dialyzer via an ultrafiltration rate and the blood flowrate corresponding to the input side of the dialyzer;
(d) determining a hematocrit value corresponding to the output side of the dialyzer via a second sensor assembly of the dialyzer test system attached to a second blood chamber of the dialyzer test system, wherein the second sensor assembly and the second blood chamber are disposed on the output side of the dialyzer;
(e) determining, using a controller of the dialyzer system, a difference in red blood cell volume between the input side of the dialyzer and the output side of the dialyzer according to the hematocrit value corresponding to the output side of the dialyzer, the hematocrit value corresponding to the input side of the dialyzer, the blood flowrate corresponding to the input side of the dialyzer, and the blood flowrate corresponding to the output side of the dialyzer;
repeatedly performing steps (a) to (e) multiple times to obtain multiple differences in red blood cell volume; and
accumulating the multiple differences in red blood cell volume to obtain the blood cell volume loss corresponding to the dialyzer, wherein accumulating the multiple differences in red blood cell volume comprises: determining, through mathematical regression, a function relating difference in red blood cell volume between the input port and the output port and time; and integrating the function over a time interval of interest.

2. The method according to claim 1 , further comprising:
determining, using the dialyzer test system, a red blood cell volume loss corresponding to a second dialyzer;
determining, using the controller of the dialyzer test system, that the red blood cell volume loss corresponding to the dialyzer is greater than the red blood cell volume loss corresponding to the second dialyzer; and
determining that the second dialyzer is of higher quality than the dialyzer.

3. A method for evaluating a dialyzer using a dialyzer test system connected to the dialyzer, the method comprising:
circulating, using a pump of the dialyzer test system, blood from a blood source through the dialyzer; and
determining, using the dialyzer test system, a red blood cell volume loss corresponding to the dialyzer, wherein determining the red blood cell volume loss corresponding to the dialyzer includes:
(a) determining a blood flowrate corresponding to an input side of the dialyzer via a calibrated pumping rate of the pump or an input flowmeter of the dialyzer test system;
(b) determining a hematocrit value corresponding to the input side of the dialyzer based on blood drawn from a first port of the dialyzer test system, wherein the first port is on the input side of the dialyzer;
(c) determining a blood flowrate corresponding to an output side of the dialyzer via an ultrafiltration rate and the blood flowrate corresponding to the input side of the dialyzer;
(d) determining a hematocrit value corresponding to the output side of the dialyzer based on blood drawn from a second port of the dialyzer test system, wherein the second port is on the output side of the dialyzer;
(e) determining, using a controller of the dialyzer system, a difference in red blood cell volume between the input side of the dialyzer and the output side of the dialyzer according to the hematocrit value corresponding to the output side of the dialyzer, the hematocrit value corresponding to the input side of the dialyzer, the blood flowrate corresponding to the input side of the dialyzer, and the blood flowrate corresponding to the output side of the dialyzer;
repeatedly performing steps (a) to (e) multiple times to obtain multiple differences in red blood cell volume; and
accumulating the multiple differences in red blood cell volume to obtain the red blood cell volume loss corresponding to the dialyzer, wherein accumulating the multiple differences in red blood cell volume comprises: determining, through mathematical regression, a function relating difference in red blood cell volume between the input port and the output port and time; and integrating the function over a time interval of interest.

4. The method according to claim 3 , further comprising:
determining, using the dialyzer test system, a red blood cell volume loss corresponding to a second dialyzer;
determining, using the controller of the dialyzer test system, that the red blood cell volume loss corresponding to the dialyzer is greater than the red blood cell volume loss corresponding to the second dialyzer; and
determining that the second dialyzer is of higher quality than the dialyzer.

5. A method for evaluating a dialyzer using a dialyzer test system connected to the dialyzer, the method comprising:
circulating, using a pump of the dialyzer test system, blood from a blood source through the dialyzer;
determining, using the dialyzer test system, a red blood cell volume loss corresponding to the dialyzer, wherein determining the red blood cell volume loss corresponding to the dialyzer includes:
(a) determining a blood flowrate corresponding to an input side of the dialyzer via a calibrated pumping rate of the pump or an input flowmeter of the dialyzer test system;
(b) determining a hematocrit value corresponding to the input side of the dialyzer via a first sensor assembly of the dialyzer test system attached to a first blood chamber of the dialyzer test system, wherein the first sensor assembly and the first blood chamber are disposed on the input side of the dialyzer;
(c) determining a blood flowrate corresponding to an output side of the dialyzer via an ultrafiltration rate and the blood flowrate corresponding to the input side of the dialyzer; and
(d) determining a hematocrit value corresponding to the output side of the dialyzer via a second sensor assembly of the dialyzer test system attached to a second blood chamber of the dialyzer test system, wherein the second sensor assembly and the second blood chamber are disposed on the output side of the dialyzer;

determining, using the dialyzer test system, a red blood cell volume loss corresponding to a second dialyzer;
determining, using a controller of the dialyzer test system, that the red blood cell volume loss corresponding to the dialyzer is greater than the red blood cell volume loss corresponding to the second dialyzer; and
determining that the second dialyzer is of higher quality than the dialyzer.

6. The method according to claim 5 , wherein determining the red blood cell volume loss corresponding to the dialyzer further comprises:
(e) determining, using the controller of the dialyzer system, a difference in red blood cell volume between the input side of the dialyzer and the output side of the dialyzer according to the hematocrit value corresponding to the output side of the dialyzer, the hematocrit va

Assignees

• Fresenius Medical Care Holdings Inc
• Fresnius Medical Care Holdings Inc

Inventors

• Barrett Louis Leegrande
• Ho Chih-Hu
• Stroup Eric

Classifications

• A61M2205/707

  Testing of filters for clogging · CPC title

• A61M2205/3334

  Measuring or controlling the flow rate · CPC title

• A61M2230/207

  hematocrit · CPC title

• A61M1/3612

  after treatment · CPC title

• A61M1/3663

  Flow rate transducers; Flow integrators · CPC title