Multi-Directional Flow Catheter for Low-Shear Dialysis
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Solution Overview
Problem
Current dialysis catheters experience high rates of blood cell hemolysis and platelet activation due to elevated shear forces, leading to thrombus formation and inefficient solute clearance, with existing solutions failing to effectively induce spiral laminar flow within the catheter lumens.
Innovation Solution
The design incorporates flow deflecting interfaces within the lumens to impart spiral laminar flow patterns over a substantial distance, reducing mechanical shear stress and minimizing recirculation, featuring spiral flow inducing structures within the arterial and venous lumens to align vortices in opposing directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high rates of blood flow are used to achieve efficient hemodialysis, then solute clearance is improved, but shear forces on blood cells increase leading to hemolysis and platelet activation
Solution Approach 1:
The catheter incorporates curved walls defining the terminal ends of apertures and spiral flow inducing structures that create curved flow paths. These curved geometries transform the flow pattern to generate spiral laminar flow, which reduces turbulent shear forces on blood cells while maintaining high flow rates necessary for efficient solute clearance during hemodialysis
Solution Approach 2:
The invention changes the flow regime parameter from laminar to spiral laminar flow by incorporating spiral flow inducing structures. This parameter change allows the flow to maintain high velocities for efficient dialysis while organizing the flow in a helical pattern that reduces disruptive shear forces on blood cells, thereby reducing hemolysis and platelet activation
2Object-affected harmful factors
If curved walls are used to create spiral flow, then platelet activation is reduced, but arterial fluid flow must change direction rapidly causing platelet activation
Solution Approach 1:
The catheter incorporates spiral flow inducing structures positioned upstream (proximal to) the aperture openings. These structures preliminarily establish spiral laminar flow patterns before the fluid reaches the aperture, allowing the flow to enter the lumen in a controlled spiral manner rather than abruptly changing direction, thereby reducing platelet activation
3Productivity
If spatial separation of intake and output ports is used to reduce recirculation, then recirculation is reduced, but the design becomes more complex and may not work in narrowed vessels
Solution Approach 1:
The invention changes the flow dynamics parameter by creating spiral laminar flow with vortices in opposing directions in arterial and venous lumens. This parameter change reduces recirculation through vortex alignment effects, achieving recirculation reduction without requiring complex spatial separation of ports, thereby maintaining simpler catheter design while effectively reducing recirculation even in narrowed vessels
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 design significantly reduces platelet activation and thrombosis risk, achieving minimal recirculation and efficient solute clearance, thereby improving the efficacy and safety of dialysis treatments.
Implementation Method 1
Spiral laminar flow is a natural phenomenon within the human vascular system which occurs at areas of blood vessel branching and high rates of blood flow. Spiral laminar flow creates helical vortices of blood which are less likely to lead to platelet adherence and aggregation, red blood cell hemolysis, or leukocyte adhesion.
Implementation Method 2
Spiral laminar flow creates helical vortices of blood which are less likely to lead to platelet adherence and aggregation
Implementation Method 3
The high rates of blood flow during hemodialysis create elevated shear forces on blood cells entering and exiting the lumens of the hemodialysis catheter, which has the potential to produce hemolysis of red blood cells and platelet activation.
Data Source
AI summary
Disclosed are catheters useful in dialysis treatment of a patient. In an example, a catheter includes a tip that has an arterial lumen that directs blood flow in the direction of a dialysis machine and a venous lumen that directs flow in a direction away from the dialysis machine. One or both of the arterial and venous lumens includes within it a spiral flow inducing structure that cause blood flow to rotate as it travels through the lumen. In particular applications the one or more spiral flow inducing structure are spiral laminar flow inducing structures.