Vascular Introducer Everted Liner Friction Reduction

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Solution Overview

Problem

Smaller arteries tend to constrict around vascular introducers, causing friction and potential trauma during withdrawal due to the constriction, making it difficult to remove the introducer from the circulatory system.

Innovation Solution

A vascular introducer design featuring a sheath with a longer liner that is everted over a core tube, allowing for low-friction withdrawal by sliding the core tube within the everted liner segment and de-verting the liner to minimize contact with the blood vessel wall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vascular introducer is inserted into a smaller artery to perform a procedure, then access to the circulatory system is achieved, but the small artery constricts around the sheath creating friction that makes withdrawal difficult and may cause trauma

Engineering Contradiction:

Improvesuccessful access and procedure completionVSAvoidwithdrawal of the sheath

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sheath is divided into an inner liner and an outer core tube that can move independently. The liner is everted over the core tube during insertion but can be de-everted during withdrawal, creating a rolling motion that reduces friction between the sheath and blood vessel wall.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The liner is designed to dynamically change its configuration from an everted state during insertion to a de-everted state during withdrawal. This dynamic transformation allows the sheath to adapt to the constriction forces in small arteries, reducing friction during the critical withdrawal phase.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the sheath is withdrawn directly without reducing contact with the blood vessel wall, then the procedure is completed, but friction and trauma to the blood vessel wall occur

Engineering Contradiction:

Improveprocedure completionVSAvoidtrauma to blood vessel wall

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The liner acts as a flexible thin film that can be everted and de-everted. During withdrawal, the liner de-verts to minimize the surface area in contact with the blood vessel wall, reducing friction and preventing trauma while still allowing the sheath to be withdrawn successfully.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If a conventional vascular introducer design is used, then access to the circulatory system is achieved, but substantial friction is created between the outer surface of the sheath and the blood vessel wall during artery constriction

Engineering Contradiction:

Improveaccess to circulatory systemVSAvoidfriction between sheath and blood vessel wall

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

Instead of trying to reduce friction by making the sheath smaller or smoother, the invention inverts the liner over the core tube. This inversion creates a configuration where the liner can be de-everted during withdrawal, effectively reversing the contact mechanics to minimize friction forces.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Facilitates easy and trauma-free withdrawal of the vascular introducer by reducing friction and preventing direct contact between the sheath and the blood vessel wall, addressing the constriction-related issues in smaller arteries.

Implementation Method 1

A distal segment of the liner is everted to cover an outer surface of a distal segment of the core tube

Methodology Applied

Scientific EffectFriction reduction through everted liner configuration: Friction

Data Source

PatentUS8603036B2Vascular introducer and method of using same

Publication Date: 2013.12.10 COOK MEDICAL TECHNOLOGIES LLC

AI summary

A vascular introducer for accessing a circulatory system of a patient includes a sheath and a dilator. The sheath includes a fitting attached at a proximal end, and includes a liner that is longer than a core tube. A proximal segment of the liner is attached to an inner surface of the core tube, but a distal segment of the liner is everted to cover an outer surface of a distal segment of the core tube. The dilator is positioned in the sheath and includes a tapered distal segment that extends beyond a distal end of the sheath. A handle is attached to the proximal end of the dilator and extends proximally from the fitting. During a procedure, a blood vessel may constrict and grip the sheath. During withdrawal of the sheath, the core tube is slid within a first portion of the everted distal segment of the liner while another portion of the liner is de-everting.