Spinning Membrane Separator Flow Control for Hemolysis Prevention

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Solution Overview

Problem

Current blood processing systems face challenges in controlling fluid flow rates during membrane separation, leading to potential hemolysis and membrane fouling, which can result in inefficient separation and contamination of blood components.

Innovation Solution

A computer-implemented method and system that uses a spinning membrane separator with a microprocessing controller to detect changes in free hemoglobin and transmembrane pressure, adjusting the flow rate to prevent overaggressive separation and minimize hemolysis, while also monitoring membrane fouling to maintain efficient filtration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the flow rate is increased to improve separation efficiency, then productivity is improved, but hemolysis and membrane fouling increase causing reliability to deteriorate

Engineering Contradiction:
Improveseparation efficiencyVSAvoidhemolysis and membrane fouling
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system continuously monitors transmembrane pressure and free hemoglobin levels, using this feedback to dynamically adjust the pump flow rate. When pressure differential exceeds a threshold or hemoglobin increases indicating hemolysis, the system automatically reduces flow rate to prevent damage while maintaining separation efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The flow rate is made dynamically adjustable based on real-time conditions rather than fixed. The pump speed varies automatically in response to changing transmembrane pressure and hemoglobin levels, allowing the system to optimize between productivity and reliability throughout the separation process

Inventive Principle:
Principle #15Dynamics

2Productivity

If aggressive separation is used to increase productivity, then separation efficiency is improved, but hemolysis increases causing harmful factors to worsen

Engineering Contradiction:
Improveseparation efficiencyVSAvoidhemolysis
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Free hemoglobin monitoring provides real-time feedback on hemolysis levels. When hemoglobin concentration increases, indicating red blood cell damage, the system automatically reduces flow rate to prevent further hemolysis while maintaining acceptable separation productivity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system takes preliminary action by monitoring transmembrane pressure and hemoglobin levels before severe hemolysis occurs. By detecting early signs of aggressive separation effects, the system preemptively adjusts flow rate to prevent harmful hemolysis while maintaining productivity

Inventive Principle:
Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively controls fluid flow rates to reduce hemolysis and membrane fouling, ensuring the integrity of separated blood components and maintaining separation efficiency, thereby increasing the yield and quality of blood products.

Implementation Method 1

providing a membrane separator configured to separate a biological fluid into filtrate and retentate

Methodology Applied
Scientific EffectMembrane filtration: Filter (physical)

Implementation Method 2

Larger molecules, such as red blood cells, may be retained within one side of the membrane, while the smaller molecules, such as plasma, may escape through the pores of the membrane

Methodology Applied
Scientific EffectSize exclusion: Porosity

Implementation Method 3

detecting a change of free hemoglobin within the plasma with an optical sensor

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Implementation Method 4

detecting a change in transmembrane pressure within the spinning membrane separator with a pressure sensor

Methodology Applied
Scientific EffectPressure measurement: Pressure Drop

Implementation Method 5

as the whole blood is spun by the centrifuge, the heavier (greater specific gravity) components, such as red blood cells, move radially outwardly away from the center of rotation toward the outer or 'high-G' wall of the separation chamber

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 6

The lighter (lower specific gravity) components, such as plasma, migrate toward the inner or 'low-G' wall of the separation chamber

Methodology Applied
Scientific EffectDensity gradient: Density Gradient

Data Source

PatentEP3446727B1System and method of controlling membrane fluid flow using fluid output
Publication Date: 2023.03.01 FENWAL INC
  • EP3446727B1 patent drawingFigure 1
  • EP3446727B1 patent drawingFigure 2
  • EP3446727B1 patent drawingFigure 3

AI summary

A computer-implemented method for controlling fluid flow rates during a biological fluid procedure, comprising providing a membrane separator configured to separate a biological fluid into filtrate and retentate, wherein concentration of retentate exiting the membrane separator is controllable by altering a flow rate of the retentate exiting the membrane separator. The computer-implemented method also comprises detecting a change of attenuated retentate particles within the filtrate, comparing the change of attenuated retentate particles within the filtrate with a threshold level, and providing a response action comprising altering the concentration of retentate exiting the membrane separator if the change of attenuated retentate particles within the filtrate exceeds the threshold level.