Catheter Distal End Strength via Variable Lumen Width
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Solution Overview
Problem
Conventional multi-lumen catheters face issues with the strength of the distal end portion due to the presence of the expansion lumen, leading to potential damage from bending or other mechanical stress, as the main lumen is positioned eccentrically and the radial thickness is compromised.
Innovation Solution
A catheter design where the opening width of the second lumen in the distal end portion is smaller than at the proximal end portion, with a thicker radial thickness on the first lumen side, and optionally a balloon joined to the distal end, to enhance the strength and prevent excessive bending, while maintaining flow channel resistance and joint integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the expansion lumen is positioned on the outer periphery side of the main lumen with constant opening width, then the catheter structure is simple and easy to manufacture, but the distal end portion strength becomes low and susceptible to damage
Solution Approach 1:
The expansion lumen opening width is varied along the shaft length: larger at the proximal end and smaller at the distal end. This local variation in geometric quality allows the distal end to have increased radial thickness and improved strength while the proximal end maintains adequate flow capacity, resolving the contradiction between structural simplicity and distal end strength.
2Strength
If the opening width of the second lumen is reduced at the distal end portion, then the strength and radial thickness are improved, but the flow channel resistance increases
Solution Approach 1:
The expansion lumen is designed with different opening widths at different locations: the proximal end portion has a larger opening width to minimize flow resistance, while the distal end portion has a smaller opening width to increase radial thickness and strength. This local differentiation allows each section to optimize for its primary function.
Solution Approach 2:
The expansion lumen cross-sectional shape is changed from circular at the proximal end to flattened or elliptical at the distal end. This dimensional transformation reduces the opening width in the radial direction (improving strength) while maintaining or increasing the opening width in the axial direction, thereby preserving flow capacity and minimizing resistance increase.
Data Source
AI summary
A catheter having a shaft including a first lumen that communicates from the proximal end to the distal end of the shaft, and a second lumen that is positioned on the outer periphery side of the first lumen, communicates from the proximal end side to the distal end side of the shaft, and has a smaller opening area than the opening area of the first lumen in a transverse section of the shaft. The dimension in the first direction in the distal end portion of the shaft where the first lumen and the second lumen are aligned is less than or equal to the dimension in the first direction in the proximal end portion that is closer to the proximal end side than the distal end portion of the shaft.