Cannula Assembly Locking Device for Functional Strand Safety
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Solution Overview
Problem
Conventional cannula arrangements can damage medical functional strands during retraction due to the sharpened cannula tip, leading to potential complications and the need for emergency procedures to remove partially severed strands.
Innovation Solution
A cannula arrangement with a mechanical, magnetic, or electrical locking device that blocks the proximal retraction movement of the functional strand, preventing damage by the sharpened cannula tip, and allowing only distal advancement, thereby enhancing patient safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the functional strand is made movable in the lumen for insertion and removal, then the ease of operation is improved, but the reliability deteriorates due to risk of damage by the sharpened cannula tip
Solution Approach 1:
The locking device is activated before the functional strand contacts the sharpened cannula tip during retraction. The locking element engages with the functional strand and prevents further proximal movement, counteracting the potential cutting action of the tip before damage can occur.
Solution Approach 2:
The locking element acts as an intermediary between the functional strand and the sharpened cannula tip. It intercepts the retraction movement and converts it into a locking action, preventing the strand from contacting the hazardous tip region during withdrawal.
2Reliability
If a locking device is added to prevent retraction damage, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The locking device is integrated into the cannula assembly, with the locking element formed as part of the cannula tube structure. The incision in the tube wall creates a flexible locking element that combines the structural integrity of the cannula with the protective locking function, avoiding the need for separate complex locking mechanisms.
Solution Approach 2:
The locking element utilizes the elastic properties of the cannula tube material and the geometry of the incision to automatically engage and disengage. The spring-like deformation of the tube wall provides the locking force without requiring external power sources, actuators, or complex control systems.
Data Source
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AI summary
A cannula assembly of this type is known, comprising a longitudinally extending cannula tube having: a proximal inlet opening; a distal outlet opening; a lumen extending continuously longitudinally between the inlet opening and the outlet opening; and a sharpened cannula tip delimiting the outlet opening; wherein the cannula tube is designed to receive and guide a flexible functional medical thread, which can be inserted into the lumen and moved along the lumen. According to the invention, a blocking device is provided, which has at least one blocking element associated with the lumen, wherein the at least one blocking element is designed to interact with the functional thread and can be automatically transferred, depending on a movement direction of the functional thread, between a blocking position, in which the at least one blocking element blocks a proximally directed return movement of the functional thread by acting on the functional thread (F), and a release position, in which the at least one blocking element releases a distally directed advancing movement. The invention relates to the use of said cannula assembly during a catheterisation process.