Systems and methods for determining free plasma hemoglobin

Patent metadata

Field	Value
Publication number	US-9833557-B2
Application number	US-201414577124-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 19, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A system is provided for separating a plasma-containing fluid into separated plasma and a concentrated fluid. The system cooperates with a fluid flow circuit including a fluid separation chamber and a plasma outlet line associated therewith for removing separated plasma from the fluid separation chamber. The system includes an optical sensor assembly to monitor the contents of the plasma outlet line and produce an output indicative of the concentration of free plasma hemoglobin in the plasma outlet line. A controller of the system calculates the amount of free plasma hemoglobin in at least a portion of the concentrated fluid based at least in part on the output of the optical sensor assembly. The controller may periodically calibrate the optical sensor assembly by determining an instrument-specific correlation between optic output and free hemoglobin concentration and comparing it to experimentally determined data to ensure continued reliability of the optical sensor assembly.

First claim

The invention claimed is:

1. A fluid separation system for separating a plasma-containing fluid into separated plasma and a concentrated fluid, the fluid separation system being configured to cooperate with a fluid flow circuit including a fluid separation chamber and a plasma outlet line associated with the fluid separation chamber for removing separated plasma from the fluid separation chamber, the fluid separation system comprising:
an optical sensor assembly configured to monitor the contents of the plasma outlet line and produce an output indicative of the concentration of free plasma hemoglobin in the plasma outlet line;
a controller programmed to calculate the amount of free plasma hemoglobin in at least a portion of the concentrated fluid based at least in part on the output of the optical sensor assembly; and
a pump configured to deliver at least a portion of the concentrated fluid to a fluid recipient, wherein the controller is programmed to generate an alarm or alert signal when the amount of free plasma hemoglobin in the concentrated fluid delivered to and/or to be delivered to the fluid recipient meets or exceeds a preselected or predetermined value.

2. The fluid separation system of claim 1 , wherein the controller is programmed to determine the amount of separated plasma passing through the plasma outlet line during a period of time based at least in part on a pump rate of the pump during said period of time and to calculate the amount of free plasma hemoglobin passing through the plasma outlet line during said period of time by multiplying the concentration of free plasma hemoglobin in the plasma outlet line by the amount of separated plasma passing through the plasma outlet line during said period of time.

3. The fluid separation system of claim 2 , wherein the controller is programmed to calculate the total amount of free plasma hemoglobin that has passed through the plasma outlet line by calculating the amount of free plasma hemoglobin passing through the plasma outlet line during a plurality of consecutive periods of time and adding together said amounts of free plasma hemoglobin passing through the plasma outlet line during said plurality of consecutive periods of time.

4. The fluid separation system of claim 1 , further comprising a plasma weigh scale, wherein the controller is programmed to determine the amount of separated plasma that has passed through the plasma outlet line during a period of time based at least in part on a change of weight registered by the plasma weigh scale during said period of time and to calculate the amount of free plasma hemoglobin that has passed through the plasma outlet line during said period of time by multiplying the concentration of free plasma hemoglobin in the plasma outlet line by the amount of plasma that has passed through the plasma outlet line during said period of time.

5. The fluid separation system of claim 4 , wherein the controller is programmed to calculate the total amount of free plasma hemoglobin that has passed through the plasma outlet line by calculating the amount of free plasma hemoglobin that has passed through the plasma outlet line during a plurality of consecutive periods of time and adding together said amounts of free plasma hemoglobin that have passed through the plasma outlet line during said plurality of consecutive periods of time.

6. The fluid separation system of claim 1 , wherein the controller is programmed to calculate the amount of free plasma hemoglobin in said at least a portion of the concentrated fluid by calculating the amount of free plasma hemoglobin in the separated plasma and multiplying said amount of free plasma hemoglobin in the separated plasma by a ratio factor.

7. The fluid separation system of claim 1 , wherein the controller is programmed to calculate the amount of free plasma hemoglobin in said at least a portion of the concentrated fluid by multiplying the concentration of free plasma hemoglobin in the plasma outlet line by a ratio factor and by either the amount of plasma in said at least a portion of the concentrated fluid or the amount of plasma that has passed through the plasma outlet line.

8. The fluid separation system of claim 7 , wherein the controller is programmed to determine the amount of plasma in said at least a portion of the concentrated fluid based at least in part on the hematocrit of said at least a portion of the concentrated fluid.

9. The fluid separation system of claim 1 , further comprising a concentrated fluid weigh scale, wherein the controller is programmed to determine the amount of free plasma hemoglobin in said at least a portion of the concentrated fluid based at least in part on the weight of said at least a portion of the concentrated fluid.

10. The fluid separation system of claim 1 , wherein the controller includes a pre-programmed reference equation having one or more constants and representing an experimentally determined relationship between an output of the optical sensor assembly and free plasma hemoglobin concentration and is further programmed to, during a calibration test,
generate an equation having one or more constants and representing the actual relationship between the output of the optical sensor assembly and free plasma hemoglobin concentration,
compare at least one of the one or more constants of the reference equation to the corresponding constant or constants of the generated equation,
register the optical sensor assembly as having passed the calibration test if the differences between the at least one of the one or more constants of the generated equation are less than a predetermined tolerance away from the corresponding constant or constants of the reference equation, and
register the optical sensor assembly as having failed the calibration test if the differences between the at least one of the one or more constants of the generated equation are greater than a predetermined tolerance away from the corresponding constant or constants of the reference equation.

11. A method of calculating the amount of free plasma hemoglobin in a concentrated fluid separated from a plasma-containing fluid, comprising:
separating a plasma-containing fluid into separated plasma and a concentrated fluid;
optically monitoring at least a portion of the separated plasma;
generating an output indicative of the concentration of free plasma hemoglobin in said at least a portion of the separated plasma;
calculating the amount of free plasma hemoglobin in at least a portion of the concentrated fluid based at least in part on said output;
operating a pump to deliver at least a portion of the concentrated fluid to a fluid recipient; and
generating an alarm or alert signal when the amount of free plasma hemoglobin in the concentrated fluid delivered to and/or to be delivered to the fluid recipient meets or exceeds a preselected or predetermined value.

12. The method of claim 11 , further comprising determining a flow rate of a portion of the separated plasma during a period of time and calculating the amount of free plasma hemoglobin in said portion of the separated plasma during said period of time by multiplying the concentration of free plasma hemoglobin in said portion of the separated plasma by the amount of said portion of the separated plasma.

13. The method of claim 12 , further comprising calculating the total amount of free plasma hemoglobin in the separated plasma by calculating the amount of free plasma hemoglobin in a portion of the separated plasma during a plurality of consecutive periods of time and adding together said amounts of free plasma hemoglobin in said portions of the separated plasma during said p

Assignees

• Fenwal Inc

Inventors

• Thill Melissa A
• Planas Samantha M
• Patel Amit J
• Moore Courtney
• Cork William H

Classifications

• G01N21/25

  Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands · CPC title

• A61M1/3616

  Batch-type treatment · CPC title

• G01N33/491

  by separating the blood components (G01N15/05 takes precedence) · CPC title

• A61M2202/0415

  Plasma · CPC title

• A61M2205/3327

  Measuring · CPC title