Hemodialysis Catheter Opening Geometry for Low Recirculation
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Solution Overview
Problem
Existing hemodialysis catheters suffer from poor flow performance due to occlusion and recirculation issues, which are not adequately addressed by current designs that fail to optimize the circumferential and axial distances between venous and arterial openings, leading to inefficient dialysis procedures.
Innovation Solution
A catheter design with optimized venous and arterial openings defined by transversely spaced axial and transverse wall portions, featuring proximal and distal tapered configurations to maximize separation and minimize recirculation, thereby enhancing flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If staggered venous and arterial lumens are used to ensure blood returning is expelled downstream, then recirculation is reduced, but flow performance deteriorates due to occlusion in the arterial lumen
Solution Approach 1:
The catheter employs asymmetric opening configurations where the venous opening has a different geometry and orientation than the arterial opening. Specifically, the venous opening is positioned and shaped to optimize downstream blood expulsion, while the arterial opening is configured to minimize occlusion risk, creating asymmetric flow patterns that simultaneously reduce recirculation and maintain reliable flow performance
Solution Approach 2:
The invention addresses the two-dimensional lumen arrangement by introducing optimized three-dimensional opening geometries and orientations. The openings are configured with specific axial and radial dimensions and angles that create three-dimensional flow separation, allowing blood to be expelled in directions that reduce recirculation while maintaining arterial lumen patency
2Device complexity
If arterial and venous openings are positioned close together, then device complexity is reduced, but occlusion likelihood increases due to poor flow separation
Solution Approach 1:
The catheter applies local quality optimization by configuring the arterial and venous openings with distinct local geometries and orientations tailored to their specific functions. The arterial opening has characteristics optimized for blood intake with reduced occlusion risk, while the venous opening has characteristics optimized for blood expulsion, allowing close positioning without increased occlusion likelihood
Solution Approach 2:
The invention optimizes specific geometric parameters of the openings including axial spacing, radial positioning, opening angles, and cross-sectional dimensions. By carefully selecting these parameters, the catheter achieves effective flow separation and occlusion resistance even when the openings are positioned close together, reducing device complexity while maintaining reliability
3Productivity
If venous and arterial openings have large perimeter and height, then flow efficiency improves, but recirculation increases when blood lines are reversed
Solution Approach 1:
The asymmetric configuration of the openings ensures that even when blood lines are reversed, the geometric asymmetry creates unfavorable flow conditions for recirculation. The arterial opening's geometry and orientation differ from the venous opening, so reversing the lines does not create optimal conditions for clean blood to be drawn back into the catheter, maintaining low recirculation while preserving dialysis efficiency
Data Source
Figure 1
Figure 2~2B
Figure 3
AI summary
The present disclosure relates to a medical catheter including an elongate catheter member (14) defining a longitudinal axis and having a proximal end, a distal end, an outer wall (28), and first (30) and second (32) internal lumens. The outer wall of the catheter member includes a first opening (42A) in fluid communication with the first internal lumen to facilitate the establishment of a first flow stream, and a second opening (42B) in fluid communication with the second internal lumen to facilitate the establishment of a second flow stream. Each of the first and second openings includes proximal (52A) and distal (54A) tapered portions that are connected by an intermediate portion (56A) having a constant transverse dimension.; The configurations, dimensions, and positioning of the first and second openings optimizes separation of the first flow stream from the second flow stream in order to reduce the likelihood of recirculation between the first and second internal lumens.