Flush Syringe Resonance for Automatic Pulsatile Catheter Flushing

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Solution Overview

Problem

Conventional flush syringe designs require manual effort to produce pulsatile flow, which can be cumbersome and may cause discomfort to clinicians, and existing mechanical solutions often involve complex components or additional devices.

Innovation Solution

A flush syringe that utilizes fluid momentum or resonance to generate pulsatile flow without mechanical interference, using components like rotating wheels with vanes or flexible members to induce rotational velocity or resonance, reducing the need for manual effort and complex parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual pulsatile flushing is performed by alternatingly applying high and low force to the syringe plunger, then bacterial clearance from IV catheters is improved, but clinician discomfort and operational complexity increase

Engineering Contradiction:
Improvebacterial clearance efficacyVSAvoidclinician discomfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The syringe system performs pulsatile flushing automatically through its own fluid flow dynamics. The fluid momentum and pressure differentials generated during normal syringe operation cause the flexible membrane to oscillate and produce pulsatile flow without requiring external manual pulsing actions from the clinician.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical pulsing system (clinician applying alternating force to plunger) with a fluid-dynamics-based system. The pulsatile flow is generated through fluid pressure differentials acting on a flexible membrane, eliminating the need for manual mechanical pulsing while maintaining bacterial clearance efficacy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If mechanical pulsing elements are added to the syringe barrel and plunger rod, then pulsatile flow is generated, but device complexity increases

Engineering Contradiction:
Improvepulsatile flow generationVSAvoidsyringe structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent removes the complex mechanical pulsing elements (projections on plunger rod, corresponding features on barrel interior) and replaces them with a simpler flexible membrane component. The pulsatile flow is generated by fluid pressure acting on this membrane rather than through mechanical interference between rigid components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state and properties of the membrane from rigid mechanical elements to a flexible, deformable component. This allows the system to generate pulsatile flow through elastic deformation driven by fluid pressure differentials rather than through rigid mechanical projections and recesses.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If in-line pulsating devices are used to generate pressure pulses, then catheter purging is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecatheter purging efficacyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the pulsatile flow generation function directly into the syringe body structure itself, rather than using a separate in-line pulsating device. The flexible membrane is integrated into the syringe barrel, allowing the syringe to generate its own pulsatile flow without requiring additional external components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a simple, disposable flexible membrane component that can be easily manufactured and integrated into single-use syringes. This approach reduces manufacturing complexity and cost compared to more sophisticated, reusable in-line pulsating devices, aligning with the disposable nature of many medical syringes.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 syringe efficiently produces pulsatile flow with reduced clinician discomfort and lower manufacturing costs by leveraging fluid momentum or resonance, enhancing catheter flushing efficacy.

Implementation Method 1

fluid flow causing resonance of a flexible member disposed within the syringe to produce the pulsatile flow

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

A flush syringe that utilizes fluid momentum or resonance to generate pulsatile flow without mechanical interference, using components like rotating wheels with vanes or flexible members to induce rotational velocity or resonance

Methodology Applied
Scientific EffectFluid momentum: Inertia

Data Source

PatentEP4725517A2Pulsatile or resonating flush syringe
Publication Date: 2026.04.15 BECTON DICKINSON & CO
  • EP4725517A2 patent drawingFigure 1A
  • EP4725517A2 patent drawingFigure 1B
  • EP4725517A2 patent drawingFigure 2A

AI summary

A flush syringe for use in maintaining intravenous catheters, which can more efficiently and effectively flush catheters by providing a pulsating, pulsatile, and/or pulsative flow of fluid that can be produced using the momentum of the moving fluid itself. A steady force applied to the plunger while flushing can provide a pulsating flow of fluid to a catheter.