Angled-Lumen Catheter Tip for Lower Shear and Biofilm Risk
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Solution Overview
Problem
Traditional catheters face issues such as occlusion, phlebitis, infiltration, infection, and thrombus formation due to friction, shear stress, and biofilm accumulation, leading to vessel wall damage and microbial infection.
Innovation Solution
The catheter design features an angled lumen and a softer vessel-contacting portion with multiple openings to distribute fluid flow, reduce shear stress, and minimize biofilm adhesion, while maintaining centralization within the vessel to prevent drag and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a traditional smooth hydrophobic surface is used on the catheter, then the catheter is easy to manufacture and maintains structural integrity, but it attracts biofilm that leads to microbial infection
Solution Approach 1:
The catheter surface is modified with a porous hydrophilic coating that allows fluid penetration while preventing biofilm adhesion. The porous structure creates a hydrated barrier that repels microorganisms and prevents biofilm formation, directly addressing the infection risk without compromising manufacturability
Solution Approach 2:
The surface properties of the catheter are changed from hydrophobic to hydrophilic through coating application. This parameter change in surface wettability fundamentally alters the interaction with fluids and microorganisms, preventing biofilm accumulation while maintaining ease of manufacture through standardized coating processes
2Stability of the object's composition
If the catheter tip contacts the vessel wall to maintain position, then the catheter remains stable in the vessel, but friction causes damage to the endothelium and tunica intima leading to phlebitis or infiltration
Solution Approach 1:
A flexible hydrophilic coating is applied to the catheter surface, particularly at the tip portion. This thin film layer reduces friction between the catheter and vessel wall while maintaining catheter stability, preventing endothelium damage and phlebitis through its lubricating and protective properties
Solution Approach 2:
The friction coefficient between the catheter surface and vessel wall is reduced through application of a hydrophilic coating. This parameter change in surface properties decreases mechanical damage to the vessel wall while maintaining positional stability of the catheter
3Device complexity
If fluid outflow is concentrated on a small area of the vessel wall from the tip, then the catheter structure is simple, but shear stress damages endothelial cells and leads to phlebitis
Solution Approach 1:
The fluid outflow function is segmented from a single concentrated outlet to multiple distributed outlets along the catheter tip. This segmentation disperses the fluid jet across a larger area of the vessel wall, reducing shear stress on endothelial cells while maintaining relatively simple catheter construction
Solution Approach 2:
The fluid delivery is transitioned from a point-source (single outlet) to a distributed line or surface source (multiple outlets). This dimensional change in fluid ejection geometry spreads the shear stress impact across multiple endothelial cell areas, reducing localized damage
4Device complexity
If a single lumen catheter is used, then the catheter design is simple, but it is prone to thrombotic occlusion and ball-valve occlusion during aspiration
Solution Approach 1:
The single lumen is segmented into multiple lumens or flow channels within the catheter tip. This segmentation provides alternative flow paths that prevent complete occlusion by thrombus or blood components, maintaining catheter patency while keeping the overall design relatively simple
Solution Approach 2:
The flow dynamics parameters are changed by creating multiple flow channels with different orientations. This parameter change in flow geometry prevents ball-valve occlusion during aspiration by distributing negative pressure across multiple channels, maintaining reliable fluid flow
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
The design reduces the risk of phlebitis, thrombotic occlusion, and microbial infection by minimizing contact with the vessel wall, enhancing fluid flow distribution, and reducing biofilm formation, thereby improving catheter functionality and patient safety.
Implementation Method 1
The force of the fluid ejecting from the tip 113 onto the vessel wall 12a causes shear stress. Shear stress damages endothelial cells and leads to phlebitis (inflammation).
Implementation Method 2
This may cause damage to the vessel wall including erosion of the endothelium and tunica intima 12a through friction
Data Source
AI summary
A catheter for insertion into a vessel of a subject, the catheter including an elongate body extending between a proximal end configured to be attached to a hub and a distal end configured to be inserted into the vessel of the subject, the body having, a tip portion at the distal end, the tip portion having an external tapered profile and including an outlet and a lumen extending from the proximal end to the outlet. The lumen is angled to direct flow from the outlet at an angle offset from an axis of the catheter and/or at least part of the body includes a vessel contacting portion that is softer than other parts of the catheter.