Apheresis Fluid Circuit Conversion With Stagnant Blood Clearing

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Solution Overview

Problem

Existing apheresis systems face challenges in efficiently converting between single and double needle configurations, with potential stagnation of unanticoagulated blood leading to clotting and disrupting blood flow, and the need for verification of successful conversion without procedural pauses.

Innovation Solution

A system with a reusable fluid processing device and disposable circuit, utilizing valves, pumps, and a controller to convert between single and double needle configurations, including immediate post-conversion clearing of stagnant blood and monitoring parameters to ensure seamless procedure continuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the apheresis system converts between single and double needle configurations, then operational flexibility is improved, but the risk of blood stagnation and clotting increases

Engineering Contradiction:

Improveoperational flexibilityVSAvoidblood stagnation and clotting

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by automatically flushing the fluid circuit with anticoagulant solution before and during configuration conversions, and by pre-positioning valves and pumps to ensure continuous blood movement, thereby preventing stagnation and clotting before they can occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback mechanisms through sensors that detect blood flow status, pressure changes, and clot formation risks, automatically adjusting valve positions and pump speeds to maintain continuous flow and prevent clotting during configuration changes

Inventive Principle:

Principle #23Feedback

2Productivity

If the system verifies successful conversion without procedural pauses, then productivity is improved, but the complexity of the conversion process increases

Engineering Contradiction:

Improveprocedure continuityVSAvoidconversion process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system performs self-verification through automated sensors and controllers that monitor configuration status, blood flow parameters, and pressure differentials, automatically confirming successful conversion without requiring external intervention or procedural pauses

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system replaces manual verification methods with electronic sensors, microprocessors, and automated control systems that detect configuration changes through electrical and fluid dynamic parameters, reducing conversion complexity while maintaining verification accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If immediate clearing of stagnant blood is performed after conversion, then reliability is improved, but the duration of the conversion process increases

Engineering Contradiction:

Improveclotting preventionVSAvoidconversion time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system maintains continuous useful action by performing blood clearing operations simultaneously with configuration conversion through coordinated valve actuation and pump operation, eliminating idle time and ensuring uninterrupted blood flow treatment

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary flushing with anticoagulant solution before the actual configuration change occurs, pre-preparing the fluid circuit to receive and clear stagnant blood, thereby reducing the time needed for post-conversion clearing

Inventive Principle:

Principle #10Preliminary 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

Enables efficient conversion between needle configurations with minimized clotting risk and validated procedural resumption, enhancing operational flexibility and reliability in apheresis procedures.

Implementation Method 1

Whole blood is typically separated into its constituents through centrifugation

Methodology Applied

Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

one or more pumps for moving blood through the flow paths of the fluid circuit

Methodology Applied

Scientific EffectMechanical pumping: Pump

Data Source

PatentUS12558469B2Systems and methods for converting an apheresis fluid processing circuit to single or double needle mode

Publication Date: 2026.02.24 FENWAL INC

AI summary

Systems and methods for performing apheresis procedures, including photopheresis. The systems and methods utilize a disposable fluid circuit that can be converted from a double needle configuration to a single needle configuration and from a single needle configuration to a double needle configuration. A controller directs the action of system pumps to clear potentially stagnant blood residing in the fluid circuit, tracks system parameters and status before and after conversion, and verifies that the procedure may proceed in its new configuration.