Vascular Access Device Needle Length Adjustment Mechanism
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Solution Overview
Problem
Insulin syringes with fixed 6 mm needle cannulas face challenges in administering insulin without penetrating the muscle layer, leading to patient discomfort and inconsistent results, as the standard length can pass through the subcutaneous layer into the muscle, necessitating manual pinching and resulting in needlestick injuries and waste due to the need for separate needle lengths for aspiration and injection.
Innovation Solution
A vascular access device with a moveable collar and cam mechanism that adjusts the needle length from 6 mm for vial penetration to 4 mm for skin penetration, allowing full insertion into a vial while only partially inserting into the skin, reducing the risk of muscle penetration and enhancing user safety and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard 6 mm needle cannula is used to withdraw medicament from a vial, then the needle can penetrate the stopper at any angle and reach the insulin for aspiration, but the needle can pass through the subcutaneous layer into the muscle layer which is not desirable
Solution Approach 1:
The needle cannula is made movable relative to the syringe barrel through a sliding mechanism, allowing the effective needle length to be dynamically adjusted between 6 mm for vial penetration and 4 mm for skin penetration, resolving the contradiction between needing long needle for vial access and short needle to avoid muscle penetration
Solution Approach 2:
The needle assembly is divided into separable components (needle cannula and syringe barrel) that can move independently relative to each other, enabling the needle to be extended for vial penetration and retracted for skin injection, thus adapting to different operational requirements
2Ease of operation
If a 6 mm needle cannula is used for insulin injection, then the needle can reach the subcutaneous layer, but the practitioner has to pinch the site to avoid penetrating into the muscle layer which is tedious and causes patient discomfort
Solution Approach 1:
The sliding mechanism automatically adjusts the needle length to 4 mm when the syringe is positioned for skin injection, eliminating the need for manual pinching by the practitioner and thereby reducing patient discomfort while maintaining ease of operation
Solution Approach 2:
The device performs the needle length adjustment automatically based on the operational context (vial withdrawal vs. skin injection), freeing the practitioner from the tedious task of manual pinching and reducing the risk of needlestick injuries
3Object-affected harmful factors
If interchangeable needle hubs are used with separate 6 mm and smaller needle lengths, then the practitioner can avoid muscle penetration, but this results in further waste of needles
Solution Approach 1:
The invention combines multiple needle lengths (6 mm and 4 mm) into a single integrated device through the sliding mechanism, allowing the same syringe to perform both vial withdrawal and skin injection functions without requiring separate needle hubs, thereby eliminating needle waste while maintaining the ability to avoid muscle penetration
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 adjustable needle length feature ensures safe and consistent insulin administration by preventing muscle penetration, reducing patient discomfort and waste, while providing a user-friendly mechanism for precise needle exposure based on the required depth.
Implementation Method 1
The tab further includes a crescent-shaped cam having a stem and a distal peak, the distal peak extending in a distal direction in the closed position
Implementation Method 2
The tab is connected to the distal end of the outer cylindrical wall having a living hinge connecting the tab to the outer cylindrical wall. The tab is configured to pivot about the living hinge
Implementation Method 3
The moveable collar disposed within the outer cavity, the moveable collar having a proximal end and a distal end, the distal end comprising one or more snap locks configure to travel within the one or more longitudinal slots
Data Source
AI summary
Vascular access devices which have needle-length adjustment features for penetrating a vial of a stopper with the full needle length and for penetrating the skin of a patient with a desired needle length, which is less than the full needle length.