Asymmetric Catheter Tip Design for Flow Obstruction and Hemolysis

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Solution Overview

Problem

Existing vascular access devices often experience flow restrictions and blood sample quality issues due to obstructed catheter tips, leading to inefficient infusion and blood collection, and potential blood hemolysis during clinical procedures.

Innovation Solution

A vascular access device featuring an asymmetric catheter tip with a beveled leading edge, asymmetric outer and inner geometries, and strategically positioned flow holes to enhance insertion, reduce penetration force, and improve fluid flow dynamics, thereby minimizing obstruction and hemolysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional symmetric catheter tip is used, then the catheter can be manufactured with simple geometry, but the distal lumen opening may be obstructed by the inner wall of the blood vessel, restricting fluid flow

Engineering Contradiction:

Improvefluid flow rateVSAvoidcatheter tip geometry

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The catheter tip is designed with asymmetric geometry where the distal lumen opening is positioned offset from the longitudinal axis of the catheter body. This asymmetric positioning ensures that the opening does not align with the inner wall of the blood vessel, preventing obstruction and maintaining unrestricted fluid flow during infusion and blood collection procedures.

Inventive Principle:

Principle #4Asymmetry

2Productivity

If the catheter tip is positioned to maximize flow, then fluid infusion and blood collection efficiency is improved, but blood hemolysis may occur due to turbulent flow and vessel wall contact

Engineering Contradiction:

Improveblood collection efficiencyVSAvoidblood hemolysis

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The catheter tip incorporates a land portion with specific local geometric features that create a controlled flow pattern. The asymmetric positioning of the distal lumen opening combined with the land portion geometry directs blood flow away from the vessel wall and reduces turbulence, minimizing hemolysis while maintaining efficient blood collection.

Inventive Principle:

Principle #3Local quality

3Force

If a sharp needle is used for insertion, then penetration force is reduced, but the catheter may peel back from the needle during insertion

Engineering Contradiction:

Improvepenetration forceVSAvoidcatheter-needle engagement

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The catheter tip features a curved, rounded leading edge instead of a sharp angle. This curvature allows the catheter to smoothly follow the needle trajectory during insertion, preventing peel-back while working effectively with the sharp needle to minimize penetration force and tissue trauma.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentEP3522969B1Catheter with an asymmetric tip

Publication Date: 2026.02.25 BECTON DICKINSON & CO

Figure 1~2
Figure 3A~3B
Figure 4A~4B

AI summary

A catheter (12) including a proximal end, a tip (14), and a lumen (26) formed by an inner wall of the catheter that extends between the proximal end and the tip along a longitudinal axis (30). The tip of the catheter includes a distal lumen opening (58) disposed on the longitudinal axis. The tip also includes a leading edge (32). The leading edge forms the distal lumen opening and includes an upper (42a) and a lower portion (42b). The lower portion of the leading edge is disposed distally to the upper portion of the leading edge.