Double Fiber Bundle Dialyzer for Hemodiafiltration

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Solution Overview

Problem

Existing dialyzers face inefficiencies in urea and creatinine removal, tend to clot, and require additional equipment for ultrafiltration and backfiltration, especially at low dialysate flow rates, and are not compatible with standard dialysis machines for hemodiafiltration treatments.

Innovation Solution

A double-fiber bundle dialyzer design with a constricted passage between dialysate compartments to control pressure drop, enhancing ultrafiltration and backfiltration rates, and a novel end cap for uniform blood flow, allowing integration with standard dialysis equipment for efficient midsize molecule clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a standard dialyzer design is used, then it can be connected to standard dialysis machines, but it requires additional equipment for ultrafiltration and backfiltration and is inefficient at low dialysate flow rates

Engineering Contradiction:

Improvecompatibility with standard dialysis machinesVSAvoidneed for additional equipment

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines ultrafiltration and backfiltration functions into a single dialyzer unit by creating two fiber bundles within one housing, allowing both functions to be performed simultaneously without additional equipment. The first fiber bundle performs ultrafiltration while the second performs backfiltration, merging multiple functions into one device that is compatible with standard dialysis machines.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The dialyzer is segmented into two separate fiber bundles housed within a single casing. The first fiber bundle is dedicated to ultrafiltration and the second to backfiltration, allowing independent optimization of each function while maintaining compatibility with standard equipment through unified inlet and outlet connections.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If dialysate flow rate is reduced, then energy consumption decreases, but ultrafiltration and backfiltration efficiency deteriorates

Engineering Contradiction:

Improvedialysate flow energy consumptionVSAvoidurea and creatinine removal efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent creates dynamic pressure balance between ultrafiltration and backfiltration processes. By allowing backfiltration to occur simultaneously, the system maintains effective solute removal even at low dialysate flow rates, as the backpressure from the second fiber bundle compensates for reduced flow-driven clearance in the first bundle.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the pressure parameters within the dialyzer by creating two separate pressure zones - one for ultrafiltration and one for backfiltration. This allows the system to maintain effective transmembrane pressure gradients for solute removal even when overall dialysate flow rate and energy consumption are reduced.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional dialyzer design is used, then manufacturing is simple, but clotting occurs and treatment reliability decreases

Engineering Contradiction:

Improvedialyzer manufacturing simplicityVSAvoidclotting prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the pressure parameters within the dialyzer by creating two separate pressure zones - one for ultrafiltration and one for backfiltration. This allows the system to maintain effective transmembrane pressure gradients for solute removal even when overall dialysate flow rate and energy consumption are reduced.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If single fiber bundle design is used, then device complexity is low, but filtration efficiency for midsize molecules is insufficient

Engineering Contradiction:

Improvefiber bundle configurationVSAvoidmidsize molecule clearance

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 improves urea and creatinine removal, prevents clotting, eliminates the need for additional equipment, and enables efficient hemodiafiltration treatments on standard machines by optimizing filtration and backfiltration rates and ensuring uniform blood flow.

Implementation Method 1

a constricted passage between the two chambers that is dimensioned to provide a dialysate pressure drop that improves dialyzer performance

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

two bundles of hollow fibers constituted by semi-permeable membranes

Methodology Applied

Scientific EffectSemipermeable membrane filtration: Semipermeable Membrane

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

Methodology Applied

Scientific EffectFluid mixing:

Data Source

PatentUS10744251B2Double fiber bundle dialyzer

Publication Date: 2020.08.18 MIRIMEDICAL

AI summary

A dialyzer composed of: first and second dialyzation chambers, and an intermediate chamber interposed between the first and second dialyzation chambers. 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 chambers and is configured to maintain a substantially uniform blood flow.