Direct Blood Draw Flow Restriction Accessories for Hemolysis Reduction

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Solution Overview

Problem

Current blood draw methods using peripheral intravenous catheters (PIVCs) face challenges with hemolysis due to high shear stress on red blood cells, leading to sample rejection, vein and catheter collapse, and blood spillage, which are exacerbated by varying user skills in controlling suction pressure.

Innovation Solution

A flow restriction device is integrated with PIVCs to regulate blood flow rate by using a resilient valve that adjusts the cross-sectional area of the fluid path, reducing hemolysis by limiting flow when suction pressure exceeds safe limits and allowing seamless integration with existing PIVC systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a vacuum blood collection container is coupled to the catheter to draw blood, then blood collection efficiency is improved, but hemolysis of red blood cells occurs due to high shear stress from pressure differential

Engineering Contradiction:
Improveblood collection efficiencyVSAvoidhemolysis
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

A flow restriction device is introduced as an intermediary component between the vacuum blood collection container and the catheter. This device includes a flow restrictor that creates a controlled pressure differential, allowing blood to flow into the collection container while preventing excessive suction pressure that would cause hemolysis. The flow restrictor acts as a mediator that reconciles the conflicting requirements of efficient blood collection and red blood cell integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If suction pressure is increased to improve blood draw speed, then productivity is improved, but catheter tip collapse and vein collapse occur

Engineering Contradiction:
Improveblood draw speedVSAvoidcatheter and vein integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The flow restriction device incorporates a pressure-sensitive mechanism that provides feedback control of blood flow. As blood flows into the vacuum container, the pressure differential automatically adjusts through the flow restrictor to maintain optimal flow conditions. This self-regulating system prevents excessive suction pressure that would cause catheter or vein collapse while maintaining efficient blood collection, eliminating the need for manual pressure control by the user.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If manual plunger withdrawal is used to draw blood, then control over blood draw is improved, but user skill variability leads to inconsistent results and potential hemolysis

Engineering Contradiction:
Improvecontrol over blood drawVSAvoidconsistency of results
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The flow restriction device is designed to automatically regulate blood flow without requiring manual intervention or user skill. The device self-adjusts the flow rate and pressure differential based on the vacuum pressure in the collection container, eliminating variability between different users. This self-regulating mechanism ensures consistent, hemolysis-free blood collection regardless of the operator's experience level.

Inventive Principle:
Principle #25Self-service

4Productivity

If high flow rate is maintained during blood draw, then productivity is improved, but blood spillage occurs during and after blood draw

Engineering Contradiction:
Improveblood draw rateVSAvoidblood spillage
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The flow restriction device dynamically adjusts the flow rate throughout the blood collection process. Initially, it allows higher flow rates to quickly fill the collection container, then automatically reduces flow as the container approaches full capacity. This dynamic control prevents overfilling and subsequent blood spillage, while maintaining high productivity during the main collection phase. The system adapts its flow characteristics to the changing conditions of the collection process.

Inventive Principle:
Principle #15Dynamics

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 flow restriction device effectively reduces hemolysis and blood spillage by controlling fluid flow, maintaining blood quality and ensuring efficient blood collection without altering existing clinical operations.

Implementation Method 1

a resilient valve that adjusts the cross-sectional area of the fluid path, reducing hemolysis by limiting flow when suction pressure exceeds safe limits

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

A flow restriction device is integrated with PIVCs to regulate blood flow rate by using a resilient valve that adjusts the cross-sectional area of the fluid path

Methodology Applied
Scientific EffectFluid flow resistance: Drag

Data Source

PatentEP4498912B1Hemolysis-reduction accessories for direct blood draw
Publication Date: 2025.08.06 CAREFUSION 303 INC
  • EP4498912B1 patent drawingFigure 1
  • EP4498912B1 patent drawingFigure 2
  • EP4498912B1 patent drawingFigure 3

AI summary

A flow restriction device including a housing forming a fluid flow path with a resilient valve positioned between first and second segments of the fluid path, where a segment of the fluid path includes a spiral or involute shape, and where the resilient valve is responsive to a change in pressure along the fluid path such that the resilient valve can move or bias toward the fluid path to restrict a fluid flow through the fluid path, thereby reducing a flow rate and pressure of the fluid, and where the fluid is blood, reducing the hemolysis index of the blood, and in some instances the resilient valve stopping the fluid flow through the fluid flow path responsive to exceeding a pressure along the fluid path to reduce the hemolysis index of the blood.