IV Catheter Relief Structure for Flashback Indication
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Solution Overview
Problem
Existing IV catheter designs face challenges in providing a reliable, early indication of needle entry into a vein without creating a leak path for blood, particularly when using notches or windows that can lead to blood escape.
Innovation Solution
The introduction of an introducer needle with a relief structure that allows flashback blood to flow directly into the flash space between the needle and catheter, eliminating the need for the blood to enter the needle lumen, thereby preventing leakage and enabling optimized catheter design without lengthening the septum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a notch or window is added to the needle to provide early vein entry indication, then the visibility of flashback blood is improved, but blood leakage and loss of substance occur
Solution Approach 1:
The needle structure is segmented into distinct functional zones: the lumen for blood flow, the relief feature as a separate blood diversion path, and the sealed catheter interface. This segmentation allows blood to be directed through specific pathways (via the relief feature) without compromising the overall seal, providing visual indication while preventing uncontrolled leakage.
Solution Approach 2:
The relief feature acts as an intermediary structure between the lumen and the external environment. It provides a controlled interface that allows blood to reach the flash space for visibility while maintaining the seal between the needle and catheter, thus mediating between the need for visual indication and the need to prevent blood loss.
2Loss of substance
If the septum is lengthened to prevent blood leakage through the relief feature, then blood loss is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The blood diversion function is extracted from the septum and relocated to the relief feature on the needle. This allows the septum to maintain its original length and simple structure while the relief feature handles the blood flow diversion, reducing manufacturing complexity while still preventing blood leakage.
Solution Approach 2:
The relief feature is pre-configured on the needle during manufacturing to create the blood diversion pathway. This preliminary structuring eliminates the need for complex septum modifications during assembly, as the blood flow control is already built into the needle design.
3Difficulty of detecting and measuring
If traditional notches are used for flashback indication, then early vein entry detection is improved, but blood escape and contamination risk increase
Solution Approach 1:
The relief feature serves as an intermediary structure that allows blood to reach the flash space for detection while preventing direct exposure to the external environment. This intermediary pathway enables vein entry detection without creating open access points that could lead to contamination.
Solution Approach 2:
The seal between the needle and catheter acts as a flexible barrier that contains blood within the controlled flash space. This sealing mechanism allows visual indication while preventing blood escape and maintaining a closed system to reduce contamination risk.
Data Source
AI summary
An intravenous catheter assembly that includes a catheter tube and an introducer needle that is disposed, at least in part, within the catheter tube when the introducer needle is in a ready for use position. The introducer needle includes a lateral surface that defines a relief that is positioned under the distal end of the catheter tube when the introducer is in the ready for use position to provide a flow path into a flash indication space.