Catheter Fluid Dispersion Unit for Cryoablation
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Solution Overview
Problem
Cryoablation catheters face challenges in achieving uniform and controlled flow of cryogenic fluid to targeted tissue due to turbulent fluid flow conditions at the catheter tip, leading to irregular cooling and potential cavitation, which limits precise directional control and therapeutic effectiveness.
Innovation Solution
The catheter design incorporates a fluid dispersion unit, including a flow distribution sleeve and deflection member, to evenly distribute the cryogenic fluid across the expandable chamber, ensuring a predetermined pattern of fluid distribution and directional control, enhancing the precision of tissue ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high pressure is used to supply cryogenic fluid to the catheter tip, then the cooling effectiveness is improved, but turbulent fluid flow and cavitation occur leading to irregular fluid distribution
Solution Approach 1:
A fluid dispersion unit is introduced as an intermediary component between the supply lumen and the expandable chamber. This unit includes a flow distribution sleeve with multiple outlets that receives high-pressure cryogenic fluid and redistributes it in a controlled manner, mediating between the high-pressure supply and the need for uniform distribution to eliminate turbulence and cavitation
Solution Approach 2:
The fluid dispersion path is segmented into multiple outlets on the flow distribution sleeve rather than a single outlet. This segmentation divides the high-pressure fluid stream into multiple lower-pressure streams, reducing turbulence and cavitation while maintaining overall cooling effectiveness through distributed fluid delivery
2Ease of operation
If the catheter tip chamber is small to maintain minimally invasive properties, then ease of insertion is improved, but fluid flow becomes turbulent and directional control is reduced
Solution Approach 1:
The fluid dispersion unit adds a radial dimension to fluid distribution by incorporating multiple outlets on the flow distribution sleeve that radiate fluid in different directions. This dimensional change transforms the fluid flow from a single-directional turbulent jet into a multi-directional distributed pattern, eliminating turbulence while maintaining the small catheter profile
3Device complexity
If conventional catheter design is used with single outlet, then device complexity is reduced, but fluid distribution uniformity and directional control are insufficient
Solution Approach 1:
The fluid dispersion unit is nested within the existing catheter structure, with the flow distribution sleeve positioned inside the expandable chamber and the supply lumen passing through it. This nesting approach integrates the complex fluid distribution functionality within the existing catheter framework, achieving improved fluid distribution uniformity without proportionally increasing overall device complexity
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 improves the uniformity and control of cryogenic fluid distribution, allowing for more precise and effective tissue ablation, reducing turbulence and cavitation, and enabling the creation of targeted lesions with improved therapeutic outcomes.
Implementation Method 1
a fluid dispersion unit, including a flow distribution sleeve and deflection member, to evenly distribute the cryogenic fluid across the expandable chamber
Implementation Method 2
reducing turbulence and cavitation
Implementation Method 3
The cooling fluid used with such catheters may be a low temperature fluid, or cryogens... to cool the tissue to a much lower level at which freezing destroys the viability of the tissue
Implementation Method 4
the rate of cooling is limited by the ability to supply coolant and circulate it through the active contact region
Implementation Method 5
When the catheter contact must chill tissue to below freezing, the coolant itself must attain a substantially lower temperature
Data Source
AI summary
A medical device including an outer tube, an expandable chamber coupled to the outer tube, and an injection tubular member in fluid communication with an interior of the expandable chamber. The injection tubular member is coupled to a source of fluid and a distal end within the expandable chamber and a fluid nozzle is located in a distalmost end face of the distal end of the injection tubular member. A fluid dispersion unit is coupled to the injection tubular member with a longitudinal axis, the fluid nozzle being within the fluid dispersion unit and configured to direct a flow of fluid into the fluid dispersion unit. The fluid dispersion unit has an opening to direct a flow path of the flow of fluid expelled by the fluid nozzle within the fluid dispersion unit and into an interior surface of the expandable chamber from the opening at the distalmost end face.