Catheter Centering Wire Radial Spacing
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Solution Overview
Problem
Existing hemodialysis catheters experience decreased flow rates due to blockage of withdrawal and infusion ports, often caused by improper positioning against the vessel wall or fibrin sheath formation, leading to restricted fluid flow.
Innovation Solution
A multi-lumen catheter design featuring a radially extendable centering wire that centers the catheter within the vessel, preventing port blockage by maintaining the ports away from the vessel wall, and cut-out portions with engaged centering wires to ensure unobstructed fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catheter is positioned against the vessel wall to secure it, then the catheter is stable in position, but the ports become blocked against the vessel wall
Solution Approach 1:
The catheter design transitions from a single-plane positioning problem to a three-dimensional solution by extending the catheter body in multiple radial dimensions. The multi-lumen structure with ports positioned at different radial distances and angular orientations around the vessel wall allows the catheter to be secured against the wall while maintaining patent ports clear of the wall surface, thus preventing blockage.
Solution Approach 2:
The catheter is divided into multiple lumens with distinct functions (withdrawal, infusion, centering) positioned at different locations. The centering lumen is separated from the fluid transport lumens, allowing independent optimization of each function. This segmentation enables the centering wire to push ports away from the vessel wall while the fluid lumens maintain their own positioning.
2Device complexity
If the catheter lumens are positioned close to the vessel wall to minimize distance, then the catheter is compact, but fibrin sheaths form on the ports
Solution Approach 1:
A centering wire acts as an intermediary element between the catheter body and the vessel wall. The wire extends through the centering lumen and contacts the vessel wall, pushing the catheter lumens away from direct contact with the wall. This intermediary structure prevents fibrin sheath formation on the ports while maintaining a compact overall catheter configuration.
3Object-affected harmful factors
If the catheter ports are positioned at the distal tip to minimize insertion trauma, then the catheter causes less damage to the vessel, but the ports are more susceptible to blockage
Solution Approach 1:
Different portions of the catheter are designed with different local qualities. The distal tip maintains a compact, trauma-minimizing configuration for insertion, while the ports are positioned at specific locations along the catheter body where they can be pushed away from the vessel wall by the centering wire. This local differentiation allows the catheter to achieve both minimal trauma and port patency.
Data Source
AI summary
A catheter assembly for use in the extracorporeal treatment of bodily fluids. The assembly comprises a catheter body having a withdrawal port, an infusion port, and a plurality of lumens therein. One of the lumens comprises a withdrawal lumen for transport of fluids withdrawn from a body vessel through the withdrawal port to an extracorporeal treatment unit, such as a dialyzer. Another lumen comprises an infusion lumen for return of treated fluids from the extracorporeal treatment unit into the body vessel through the infusion port. A wire extends from yet another lumen to an attachment point on the catheter assembly. The wire is capable of bowing radially outwardly from the catheter body, in order to space the infusion and withdrawal ports from the vessel wall.