Flexible Bushing Needle Assembly for Kink-Resistant Catheter Alignment

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Solution Overview

Problem

Existing IV catheter assemblies often suffer from misalignment between the catheter tube and the catheter hub, leading to kinking, discomfort, and restricted flow due to improper alignment and movement, especially after securement, which can cause patient discomfort and affect fluid flow.

Innovation Solution

A catheter assembly featuring a bushing with a flexible elongated seat that extends out the distal end of the catheter hub, incorporating a corrugated or spiral structure to prevent kinking and align the catheter tube, coupled with a needle shield and a valve mechanism for secure fluid flow and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the catheter tube is rigidly secured to the catheter hub, then the alignment between catheter tube and hub is maintained, but the catheter tube becomes prone to kinking and restricted flow when the patient moves

Engineering Contradiction:

Improvealignment stabilityVSAvoidflexibility to patient movement

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The catheter tube is surrounded by a flexible sheath or covering that allows the tube to bend and adapt to patient movements while maintaining its structural integrity and alignment with the hub. This flexible protection layer enables the catheter system to accommodate dynamic conditions without kinking.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The catheter assembly incorporates dynamic elements such as flexible joints or articulation points between the hub and tube, allowing the system to adapt its configuration in response to patient movement. This dynamic design maintains optimal alignment while preventing kinks through controlled flexibility.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the catheter tube is made highly flexible to accommodate patient movement, then patient comfort is improved, but the alignment between catheter tube and hub becomes unstable

Engineering Contradiction:

ImproveflexibilityVSAvoidalignment stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

A flexible yet structurally supportive intermediary layer or reinforcement structure is introduced between the catheter tube and hub connection. This intermediary element provides the necessary flexibility for patient comfort while simultaneously maintaining stable alignment through its inherent structural properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The catheter tube incorporates composite material construction combining flexible polymers with reinforcing elements or coatings. This composite structure provides both the flexibility needed for patient comfort and the structural stability required to maintain proper alignment with the hub.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If a notch is added to the needle for instant blood flashback, then needle insertion verification is improved, but secondary flashback is no longer possible and blood can drip from the needle

Engineering Contradiction:

Improveblood flashback detectionVSAvoidblood dripping

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The design converts the potential harm of blood dripping from the needle by using the same notch structure that enables instant flashback to also facilitate controlled blood flow management. The notch geometry is optimized to allow visual confirmation while preventing uncontrolled dripping through surface tension management or complementary sealing features.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 bushing's flexible design maintains alignment and prevents kinking, ensuring comfortable and efficient fluid flow while providing a secure needle shield, reducing patient discomfort and enhancing catheter stability.

Implementation Method 1

The flexible portion can bend to form one or more curves along the flexible portion

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3500329B1Needle assembly and method for manufacturing the same

Publication Date: 2026.03.04 B BRAUN MELSUNGEN AG

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AI summary

Aspects of the present disclosure include catheter devices (100, 12) in which a bushing (50) is disposed in an interior cavity (92) of a catheter hub (101). The bushing (50) has a flexible portion (63) extending out a distal end (91) of the catheter hub (101). A catheter tube (140) is sleeved over the fiexible portion (63). A needle hub (102) with a needle (110) projects through the fiexible portion (63) of the bushing (50) and the catheter tube (140). The flexible portion (63) is bendable to form at least one curve (67) along the fiexible portion (63). The at least one curve (63) has a minimum bend radius when a first surface of the flexible portion (63) is extended and a second surface opposite the first surface of the flexible portion (63) is shortened.