Low-Profile Catheter Extension with Snap-Fit Cantilever Arms

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Solution Overview

Problem

Existing catheters and luer fittings are bulky and have sharp edges that can irritate or damage the skin, particularly in elderly or neonate patients, and increase the risk of catheter dislodgement.

Innovation Solution

A low-profile extension is coupled to the catheter adapter, featuring cantilever arms that engage in a snap-fit with the adapter, allowing the adapter to sit closer to the skin and reducing the risk of dislodgement while providing stability and preventing skin irritation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a male luer fitting and/or female luer fitting are used to couple the catheter to tubing, then fluid infusion capability is provided, but the bulkiness and sharp edges of the fittings may irritate or damage patient skin and increase the risk of catheter dislodgement

Engineering Contradiction:
Improvecatheter stabilityVSAvoidskin irritation and dislodgement risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A low-profile extension is introduced as an intermediary component between the catheter adapter and the luer fitting. This extension has a distal end that couples to the catheter adapter and a proximal end that receives the luer fitting, thereby mediating the connection and allowing the catheter adapter to sit closer to the skin while the bulkier luer fitting is positioned remotely

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The catheter assembly is segmented into distinct functional components: the catheter itself, the catheter adapter, the low-profile extension, and the luer fitting. This segmentation allows each component to be optimized independently - the catheter adapter can be designed for skin contact with a low profile, while the luer fitting can be designed for secure fluid connection at a remote location

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the catheter adapter is positioned away from the skin to accommodate bulky luer fittings, then skin irritation is reduced, but the catheter insertion depth decreases and dislodgement risk increases

Engineering Contradiction:
Improveskin irritationVSAvoidcatheter stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The low-profile extension acts as a mediator that decouples the position of the catheter adapter from the position of the luer fitting. The extension's distal end attaches to the catheter adapter allowing it to sit close to the skin, while the proximal end extends outward to receive the luer fitting, thus resolving the spatial conflict between skin contact requirements and fitting accommodation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the catheter adapter sits close to the skin with a low-profile design, then skin irritation is reduced and catheter stability is improved, but the luer connection becomes difficult to manipulate

Engineering Contradiction:
Improvecatheter stabilityVSAvoidluer connection manipulation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The low-profile extension extends the luer connection interface in a longitudinal dimension away from the skin surface. By projecting the proximal end of the extension outward, the luer fitting can be manipulated at a remote location that is easily accessible to the user, while the distal end remains close to the skin to maintain catheter stability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 extension stabilizes the catheter, reduces skin irritation, and minimizes the risk of accidental dislodgement by maintaining a low-profile and secure connection, facilitating remote manipulation of the luer connection.

Implementation Method 1

Each of the cantilever arms deflects as the hook of the corresponding cantilever arm is inserted into a corresponding slot of the catheter adapter. As the hook reaches a groove proximate the slot, the cantilever arm returns to an original shape of the cantilever arm prior to insertion into the slot.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3606590B1Low-profile extension for a catheter assembly
Publication Date: 2025.08.06 BECTON DICKINSON & CO
  • EP3606590B1 patent drawingFigure 1
  • EP3606590B1 patent drawingFigure 2
  • EP3606590B1 patent drawingFigure 3A

AI summary

An extension for a catheter assembly may include a distal end and a proximal end. The distal end may include one or more cantilever arms and an insertion feature spaced apart from the cantilever arms. The insertion feature may be configured to insert into a lumen of a catheter adapter to provide a fluid connection between the catheter adapter and the extension. The one or more cantilever arms may be configured to engage in a snap-fit with the catheter adapter. The proximal end of the extension may include a female luer fitting.