Double Fiber Bundle Dialyzer with Intermediate Chamber for Clotting Prevention
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Solution Overview
Problem
Existing dialyzers face issues with clotting and reverse ultrafiltration alarms due to high membrane surface areas and filtration rates, and require additional equipment and complex fluid management systems for effective midsize molecule removal during hemodiafiltration treatments.
Innovation Solution
A double fiber bundle dialyzer design with semi-permeable membranes, featuring an intermediate chamber for blood mixing and separate dialysate compartments with a constricted passage for optimized ultrafiltration and backfiltration, allowing for increased membrane surface area without clotting and simplifying fluid management by integrating with standard dialysis machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high membrane surface area is used to increase dialysis efficiency, then midsize molecule clearance is improved, but clotting and reverse ultrafiltration alarms occur
Solution Approach 1:
The dialyzer is divided into two separate fiber bundles (first and second bundles) with an intermediate chamber between them. Blood flows through the first bundle, mixes in the intermediate chamber, then flows through the second bundle. This segmentation allows the high membrane surface area to be distributed across two bundles, maintaining high clearance efficiency while reducing the risk of clotting in any single bundle by improving flow distribution and reducing stagnation zones.
2Productivity
If additional equipment is added to achieve effective midsize molecule removal, then dialysis effectiveness is improved, but device complexity increases
Solution Approach 1:
The dialyzer integrates multiple functions into a single unit: two fiber bundles for filtration, an intermediate chamber for blood mixing, and integrated ultrafiltration/backfiltration capabilities. This merging eliminates the need for separate external equipment for midsize molecule removal, simplifying the overall system while maintaining high effectiveness. The dual-bundle design with intermediate chamber provides inherent fluid management without requiring complex external fluid management systems.
3Reliability
If blood flow is increased to prevent clotting, then clotting prevention is improved, but ultrafiltration efficiency decreases
Solution Approach 1:
The intermediate chamber provides a localized region for blood mixing and residence time extension without affecting the overall blood flow rate through the dialyzer. Blood slows down locally in the intermediate chamber to allow mixing and prevent clotting, then accelerates again as it enters the second fiber bundle. This local modification of flow characteristics prevents clotting while maintaining high ultrafiltration efficiency in the fiber bundles where the actual filtration occurs.
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 enhances midsize molecule clearance, prevents clotting, and simplifies the dialysis process by eliminating the need for additional equipment, achieving efficient ultrafiltration and backfiltration while maintaining pharmaceutical-grade fluid quality without requiring external pumps or filters.
Implementation Method 1
a first bundle and a second bundle of hollow fibers constituted by semi-permeable membranes... arranged to be connected to a standard dialysis machine via a blood inlet and outlet and a dialysate inlet and outlet
Implementation Method 2
The dialyzer further includes an intermediate chamber in which blood flows from one fiber bundle to the other so that the blood coming from the first fiber bundle becomes intermixed
Implementation Method 3
blood flows from one fiber bundle to the other so that the blood coming from the first fiber bundle becomes intermixed and thus homogenized
Implementation Method 4
an intermediate chamber in which blood flows from one fiber bundle to the other
Data Source
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AI summary
A dialyzer composed of: first and second dialyzation chambers, and an intermediate chamber interposed between the first and second dialyzation chambers. Each dialyzation chamber has opposed first and second ends and contains a filter member that separates the chamber into a blood compartment and a dialysate compartment. Each of the compartments extends between first and second ends. Each of the chambers has a respective one of a blood inlet or outlet and a dialysate inlet or outlet arranged so that blood and dialysate flow in counter-current to one another in both chambers. The intermediate chamber is connected to form a dialysate-free blood flow passage between the blood compartments.