Trimmable Catheter Distal Stability Flared Design

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Solution Overview

Problem

Catheters often cause vessel damage and occlusion due to instability and whipping of the distal tip during fluid infusion, especially during power injection, as they are not adequately designed to maintain stability within the vasculature.

Innovation Solution

A catheter design with a distal portion that is flared to increase the cross-sectional size and area moment of inertia, and optionally with a higher elastic modulus than the proximal portion, to prevent whipping and ensure stability during fluid infusion, allowing for enhanced tip stability and reduced vessel damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the catheter tube is made with uniform stiffness throughout, then the proximal portion can be easily inserted into small vessels, but the distal portion becomes unstable and whips during fluid infusion

Engineering Contradiction:

Improveease of insertionVSAvoiddistal portion stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The catheter tube is designed with varying stiffness along its length: the proximal portion has lower stiffness (lower elastic modulus) to facilitate easy insertion into small vessels, while the distal portion has higher stiffness (higher elastic modulus) to maintain stability and prevent whipping during fluid infusion. This gradient in mechanical properties resolves the contradiction between ease of insertion and distal stability.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the distal portion cross-sectional size is increased to improve stability, then whipping is reduced, but the catheter may occlude smaller vessels

Engineering Contradiction:

Improvedistal portion stabilityVSAvoidvessel occlusion

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The catheter tube features a distal portion with increased cross-sectional area (flared design) that provides greater stability and reduces whipping during fluid infusion. The proximal portion maintains a smaller cross-sectional area to fit within small vessels without causing occlusion. This spatial variation in cross-sectional dimensions resolves the contradiction between stability and vessel compatibility.

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If the distal portion area moment of inertia is increased to prevent whipping, then fluid infusion stability improves, but the catheter becomes more rigid and harder to insert

Engineering Contradiction:

Improvefluid infusion stabilityVSAvoidease of insertion

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The catheter tube is designed with the distal portion having a larger area moment of inertia (through increased cross-sectional dimensions) to prevent whipping and ensure stability during fluid infusion. The proximal portion maintains a smaller area moment of inertia to remain flexible and easy to insert into the vasculature. This localized variation in geometric properties resolves the contradiction between infusion stability and ease of insertion.

Inventive Principle:

Principle #3Local quality

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 design effectively prevents distal tip whipping and maintains stability during power injection, reducing the risk of vessel damage and ensuring smooth fluid infusion by increasing the area moment of inertia and elastic modulus of the distal portion relative to the proximal portion.

Implementation Method 1

the arithmetic product of an elastic modulus and an area moment of inertia for at least a portion of the distal portion of the catheter tube defined by the catheter tube material is greater relative the arithmetic product of an elastic modulus and an area moment of inertia for at least a portion of the proximal portion of the catheter tube

Methodology Applied

Scientific EffectArea moment of inertia: Moment of Inertia

Implementation Method 2

Methodology Applied

Scientific EffectElastic modulus: Elasticity

Data Source

PatentEP4122523A1Trimmable catheter including distal portion stability features

Publication Date: 2023.01.25 CR BARD INC

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AI summary

A catheter assembly, comprising: a catheter tube (12) for insertion into a vessel of a patient, the catheter tube defining at least one lumen (14) and configured to withstand power injection, the catheter tube including: a proximal portion (20) at least a portion of which defines a first cross sectional size that is sized to reside in a relatively distal portion of the vessel; and a distal portion (30) defining a second cross sectional size that is sized larger relative the first cross sectional size so as to prevent whipping of a distal tip of the catheter tube positioned at a target position within the vessel during infusion of a fluid through the catheter tube into the vessel.