Catheter Assembly with Needle Deflection and Side-Flow Support
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Solution Overview
Problem
Existing catheter assemblies face difficulties in blood suction due to the catheter distal end adhering to the blood vessel wall or being crushed, and the inner needle deflecting during puncture, especially with longer catheters for intravenous infusion.
Innovation Solution
A catheter assembly with a deflection suppression mechanism that supports the inner needle via the catheter, featuring a side flow path structure with liquid passages and a sliding contact support portion to prevent deflection and damage, while allowing stable puncture and effective blood suction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the catheter is made longer for intravenous infusion, then the infusion capability is improved, but the inner needle deflects during puncture
Solution Approach 1:
The catheter assembly is divided into distinct functional segments: the inner needle for puncture, the catheter for infusion, and the deflection suppression mechanism as a separate functional unit. This segmentation allows each component to be optimized independently - the needle for sharp puncture and the catheter for flexible infusion delivery.
Solution Approach 2:
The deflection suppression mechanism acts as an intermediary between the inner needle and the operator. It provides intermediate support to the needle during the puncture process, preventing deflection without requiring the operator to apply excessive force or manipulate the needle directly.
2Length of moving object
If the catheter distal end is positioned to access deep vessels, then the infusion capability is improved, but the catheter distal end adheres to the blood vessel wall or gets crushed during blood suction
Solution Approach 1:
The blood suction function is segmented from the single distal end to multiple locations along the catheter body. By providing liquid passages at multiple positions including the distal end and along the body, the system ensures reliable blood access even if one location becomes obstructed or adheres to the vessel wall.
Solution Approach 2:
The liquid passages are distributed along the longitudinal dimension of the catheter rather than concentrated at the distal tip. This dimensional distribution of flow paths ensures that blood can be accessed from multiple points along the catheter's length, preventing total suction failure.
3Stability of the object's composition
If the sliding contact support portion is positioned closer to the distal side, then the needle deflection suppression is improved, but the liquid passage is damaged
Solution Approach 1:
The sliding contact support portion is positioned at a specific location along the catheter - closer to the proximal side than the most distal liquid passage. This localized positioning provides needle support exactly where needed during insertion while leaving the liquid passages in safe zones that will not be damaged by the support mechanism.
Solution Approach 2:
The catheter is functionally segmented into zones: a support interaction zone where the sliding contact support portion operates, and a protected zone where the liquid passages are located. This spatial segmentation allows the support mechanism to function without interfering with the liquid passage integrity.
4Productivity
If the catheter is advanced with respect to the inner needle, then the puncture is completed, but the sliding resistance varies
Solution Approach 1:
The sliding contact support portion provides automatic, self-regulating support during catheter advancement. As the catheter moves relative to the inner needle, the support portion naturally maintains contact and provides consistent friction-based support without requiring external control or adjustment, reducing variation in sliding resistance.
Data Source
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AI summary
A catheter assembly includes a catheter, an inner needle, and a deflection suppression mechanism that suppresses a deflection of the inner needle. A side flow path structure having at least one liquid passage is provided on a circumferential wall of the catheter. The deflection suppression mechanism has a sliding contact support portion that can support the catheter while rubbing against the catheter when the catheter is advanced with respect to the inner needle. In an initial state, the sliding contact support portion is located to be closer to a proximal side than a liquid passage located on a most distal side in the side flow path structure.