Implantable Injection System Synchronization Mechanism
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Solution Overview
Problem
The existing injection systems for implantable catheter chambers often result in residual blood volume due to suboptimal over-pressure generation during needle extraction, leading to fibrin deposition and potential obstruction, necessitating frequent chamber replacement.
Innovation Solution
The injection system incorporates synchronization means that activate the over-pressure generating means only when the needle is within the implantable chamber during extraction, utilizing a flexible segment and cam surface mechanism to ensure efficient liquid flow and minimize blood entry, with additional features like a clip to cover the injection conduit upstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-pressure generation means are provided in the extraction assembly to generate over-pressure in the injection conduit during needle extraction, then blood entry into the catheter is reduced, but the over-pressure generation is not optimized and residual blood volume remains
Solution Approach 1:
The extraction assembly is divided into distinct functional segments: the needle holder for securing the needle, the push element for extraction force, the flexible segment for over-pressure generation, and the cam surface for synchronized activation. This segmentation allows each component to perform its specific function optimally while reducing overall complexity.
Solution Approach 2:
The flexible segment is pre-positioned and pre-loaded in the inactive state within the extraction assembly. The cam surface is pre-configured to activate the flexible segment at the precise moment when the needle tip exits the septum, ensuring over-pressure is generated in advance of blood potential entry, maximizing effectiveness while minimizing residual blood volume.
2Reliability
If the generating means is activated during the entire needle extraction phase, then over-pressure is continuously generated, but blood can still enter the catheter when the needle is fully removed
Solution Approach 1:
The cam surface is designed to activate the flexible segment precisely when the needle tip emerges from the septum, creating over-pressure in advance of the critical moment when the catheter opening becomes exposed to negative pressure. This preliminary anti-action counteracts the suction effect before blood can enter the catheter, improving blood prevention efficiency while avoiding unnecessary energy consumption during later extraction phases.
Solution Approach 2:
The cam surface mechanism provides mechanical feedback based on the needle's extraction position. As the needle moves outward, the cam surface geometry automatically triggers the flexible segment activation at the optimal moment, creating a self-regulating system that applies over-pressure only when needed based on the real-time extraction state, optimizing energy usage while maintaining reliable blood prevention.
3Measurement precision
If a rigid structure is used for over-pressure generation, then precise control is achieved, but the structure cannot accommodate needle movement variations
Solution Approach 1:
The flexible segment replaces a rigid over-pressure generation mechanism with a dynamic, elastically deformable component. This flexible element can adapt to variations in needle extraction speed, angle, and position while the cam surface provides the necessary geometric constraints to ensure precise activation timing. The combination maintains measurement precision through the cam's fixed geometry while gaining adaptability through the flexible segment's ability to deform and reset with each extraction cycle.
Solution Approach 2:
The flexible segment changes its physical state from a compressed elastic state to an expanded state during needle extraction, dynamically adjusting its volume and pressure generation characteristics. This parameter change allows the system to accommodate variations in needle movement while maintaining consistent over-pressure activation timing through the cam surface's fixed geometric profile, combining adaptability with precision.
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
This approach significantly reduces or eliminates residual blood volume at the catheter end, preventing obstruction and extending the lifespan of the implantable chamber by optimizing over-pressure generation during needle extraction.
Implementation Method 1
a flexible segment (62) formed in the injection conduit (30), a cam surface (64) integral with the push element (60) and a bearing surface (66) integral with the base (26), to compress said flexible segment (62) between the cam surface (64) and the bearing surface (66)
Implementation Method 2
When the needle is removed, it adheres to the septum, which rises, the inner volume of the chamber increases, thereby creating strong suction
Implementation Method 3
the inner volume of the chamber increases, thereby creating strong suction. This suction is at the catheter end that is generally located in a blood vessel. Blood then comes into the lumen of the catheter
Data Source
AI summary
The invention relates to a system for injecting a liquid into a body, comprising an implantable chamber disposed under the skin and an injection device including: a base bearing an injection needle having a free end that is intended to be inserted into the chamber; an injection conduit connected to the needle; means for extracting the needle; means that can be actuated to generate excess pressure in the injection conduit; synchronization means between the extraction means and the generation means for actuating the generation means during a needle extraction phase. The synchronization means can essentially only actuate the generation means when the free end of the needle is located in the chamber during the needle extraction phase.