Composite Catheter Needle for Flashback Detection

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Solution Overview

Problem

Conventional cannulation systems face challenges in visualizing primary flashback due to the need for additional processing steps and potential blood exposure when using notched metal needles, which complicate manufacturing and increase discomfort for patients.

Innovation Solution

A catheter assembly with a needle tip made from a rigid material, such as metal, and a shaft made from a light-permeable material, like plastic, allowing for visible detection of primary flashback without the need for notches, and enabling easier fabrication and reduced patient discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If notched metal needles are used to enable visualization of primary flashback, then flashback detection is improved, but manufacturing complexity and processing steps increase

Engineering Contradiction:
Improveprimary flashback detectionVSAvoidneedle manufacturing complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The needle is constructed as a composite structure with a metal needle tip (first material) providing rigidity and sharpness, and a plastic needle shaft (second material) providing light permeability for flashback visualization. This composite construction eliminates the need for notching while achieving both penetration effectiveness and visual detection capabilities.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the needle have different material properties optimized for their specific functions: the needle tip uses rigid metal for effective puncture, while the needle shaft uses light-permeable plastic for flashback visualization. This local differentiation of material qualities resolves the contradiction between detection capability and manufacturing complexity.

Inventive Principle:
Principle #3Local quality

2Difficulty of detecting and measuring

If notched metal needles are used for flashback visualization, then primary flashback can be observed, but blood exposure risk increases upon needle withdrawal

Engineering Contradiction:
Improveprimary flashback detectionVSAvoidblood exposure risk
Core Design Contradiction:
Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The light-permeable plastic needle shaft allows visualization of primary flashback without creating open notches that would cause blood exposure. The solid structure of the plastic shaft maintains needle integrity while enabling optical detection of blood flow, thereby eliminating the harmful effect of blood exposure.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If metal needles are used for low penetration force, then patient discomfort is reduced, but flashback visualization requires additional processing steps

Engineering Contradiction:
Improvepatient discomfortVSAvoidneedle manufacturing simplicity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The needle is divided into two separate components manufactured from different materials: a metal needle tip for low penetration force and patient comfort, and a plastic needle shaft for light permeability and simplified manufacturing. The components are subsequently assembled, combining the advantages of both materials without requiring complex processing of metal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By combining metal and plastic materials in a single needle structure, the invention achieves both low penetration force (from the metal tip) and simplified manufacturing (from the molded plastic shaft), eliminating the need for additional processing steps required for notched metal needles.

Inventive Principle:
Principle #40Composite materials

4Difficulty of detecting and measuring

If light-permeable material is used for the needle shaft, then primary flashback visualization is enabled, but needle rigidity may be reduced

Engineering Contradiction:
Improveprimary flashback detectionVSAvoidneedle rigidity
Core Design Contradiction:
Difficulty of detecting and measuringVSStrength

Solution Approach 1:

The composite construction with metal tip and plastic shaft optimizes the rigidity-strength balance: the metal tip provides sufficient rigidity for accurate insertion, while the plastic shaft provides adequate structural integrity for flashback visualization. The assembly achieves both optical permeability and mechanical strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Rigidity is concentrated where most needed (at the needle tip for puncture accuracy) using metal, while the shaft portion uses lighter plastic material optimized for light transmission. This local differentiation of material properties resolves the contradiction between rigidity and light permeability.

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 solution allows for effective visualization of primary flashback while reducing manufacturing complexity and patient discomfort, maintaining low penetration force and facilitating cost-effective production.

Implementation Method 1

the second material is a light permeable material to enable visible detection of primary flashback in the needle shaft

Methodology Applied
Scientific EffectLight permeability: Light

Data Source

PatentEP4142588B1Catheter assembly
Publication Date: 2024.07.31 B BRAUN MELSUNGEN AG
  • EP4142588B1 patent drawingFigure 1
  • EP4142588B1 patent drawingFigure 2~3
  • EP4142588B1 patent drawingFigure 4A~4B

AI summary

A needle assembly (1400), such as a catheter assembly, having a needle shaft (12) with a needle tip (14) formed from a first rigid material for puncturing a subject. The shaft section (12), proximal of the needle tip (14) can be formed from a second material different from the first material. The needle tip (14) is attached to the needle shaft (12) to form the needle (10). The first material can have higher rigidity than the second material and the needle (10) can project through a catheter tube (18) and used in a catheter assembly.