Soft Cannula Radial Openings for Infusion Flow and Kinking
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Solution Overview
Problem
Existing infusion devices face challenges in being cost-effective, user-friendly, and resistant to kinking while maintaining efficient fluid delivery and absorption, particularly for medications like insulin.
Innovation Solution
The infusion device features a cannula with a subcutaneously placed distal portion made of soft material, equipped with radial openings that extend through one wall of the tubular body member, allowing for efficient drug discharge and minimizing kinking risks, coupled with a hub for skin attachment and a pump for fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the diameter of the cannula is reduced to minimize insertion pain, then the comfort of injection is improved, but the flow rate of fluid drug rapidly decreases
Solution Approach 1:
The single outlet at the distal end is segmented into multiple radial openings distributed along the distal portion of the cannula. This segmentation allows the flow rate to be distributed across multiple smaller openings, maintaining adequate fluid delivery while keeping each opening small enough to minimize insertion pain.
Solution Approach 2:
The fluid delivery is transitioned from a single-point outlet at the distal end to a distributed pattern of radial openings along the lateral surface of the distal portion. This dimensional change from one-dimensional (axial) to two-dimensional (radial distribution) enables improved flow characteristics without increasing outlet diameter.
2Object-affected harmful factors
If the diameter of the cannula is reduced to improve comfort, then the comfort of injection is improved, but the pressure required to move fluid increases
Solution Approach 1:
The pressure load is segmented and distributed across multiple radial openings rather than concentrated at a single outlet. This distribution reduces the pressure required at each individual opening, making the system more suitable for patient self-administration.
Solution Approach 2:
The pressure application is changed from axial (at the distal tip) to radial (through lateral openings). This dimensional change allows pressure to be applied more efficiently across the tissue interface, reducing the overall pressure requirements.
3Productivity
If radial openings are added to increase flow rate, then the delivery efficiency is improved, but the device complexity increases
Solution Approach 1:
The distal portion is made from flexible soft material that can be formed with integrated radial openings. This flexibility allows the radial openings to be created through simple forming processes rather than complex machining, reducing manufacturing complexity while maintaining the flow rate benefits.
Solution Approach 2:
The material parameter is changed from rigid to flexible soft material for the distal portion. This parameter change enables simpler manufacturing methods for creating radial openings and allows the structure to adapt to tissue contours, reducing overall device complexity.
4Reliability
If the distal portion is made from soft material to reduce kinking, then the resistance to kinking is improved, but the structural strength decreases
Solution Approach 1:
Different portions of the cannula have different material properties: the proximal portion maintains higher strength for structural integrity, while the distal portion uses softer material for kinking resistance. This local differentiation of material quality optimizes both strength and flexibility where needed.
Solution Approach 2:
The cannula employs a composite structure with different material properties in different sections. The combination of harder proximal material and softer distal material creates a composite system that achieves both structural strength and kinking resistance simultaneously.
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 configuration enhances fluid absorption rates, reduces pressure requirements for injection, and mitigates kinking issues, providing a cost-effective and user-friendly solution for subcutaneous infusion.
Implementation Method 1
The distal portion is provided with a radial opening allowing a portion of a drug conveyed through the tubular body member to discharge
Implementation Method 2
The distal portion may be made from soft material
Data Source
AI summary
An infusion device (50) incl. a preferably soft cannula (1) configured to be inserted by means of an insertion needle. The cannula has a tubular body member having a proximal end and a subcutaneously placed distal portion having a distal end where the distal portion is provided with an opening (2) allowing a portion of a drug conveyed through the tubular body member to discharge. The cannula further comprise, in the distal portion, a radial opening allowing a portion of a drug conveyed through the tubular body member to discharge.