Dialysis Filtration Rate Controller for Fluid Balance

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Solution Overview

Problem

Current bodily fluid treatment devices, such as dialysis apparatus, face challenges in effectively controlling filtration rates to prevent complications like hypotension and intradialytic symptomatology, as existing feedback control methods are not comprehensive enough to manage fluid balance accurately.

Innovation Solution

A controller system that calculates and adjusts filtration rates based on pre-defined target relations between substance concentration and distribution space in a patient's body, using measured values and a database to output signals for precise control, incorporating methods like ultrafiltration boluses and steady-state curve approximation to maintain optimal fluid balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional feedback control methods are used to control filtration rates, then some level of fluid balance management is achieved, but the control is not comprehensive enough to prevent hypotension and intradialytic symptomatology

Engineering Contradiction:
Improvefluid balance control reliabilityVSAvoidcontroller system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a comprehensive feedback control system that continuously monitors multiple patient parameters (weight, blood pressure, ultrafiltration volume) and adjusts the filtration rate dynamically. The controller compares actual measurements with target values and modifies the ultrafiltration profile in real-time to maintain fluid balance while preventing hypotension and intradialytic symptoms, thereby resolving the contradiction between control reliability and system complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary calculations of target ultrafiltration volumes and rates before initiating dialysis treatment based on patient-specific parameters. By pre-determining the optimal filtration profile and adjusting it during treatment based on feedback, the system achieves reliable fluid balance control without requiring overly complex real-time decision-making, thus managing the trade-off between reliability and complexity.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If higher filtration rates are applied to improve treatment efficiency, then productivity increases, but unwanted blood pressure drops and symptoms like nausea and vertigo occur

Engineering Contradiction:
Improvedialysis treatment efficiencyVSAvoidblood pressure drops and intradialytic symptoms
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic adjustment of filtration rates throughout the dialysis treatment. Instead of maintaining a constant high filtration rate, the system continuously adapts the ultrafiltration profile based on real-time patient responses, weight changes, and blood pressure measurements. This dynamic approach allows the treatment to proceed efficiently while preventing harmful effects by reducing filtration rates when symptoms arise or blood pressure drops occur.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes multiple parameters simultaneously including ultrafiltration volume, filtration rate, and treatment duration to optimize both productivity and patient safety. By adjusting these parameters based on feedback from weight measurements and blood pressure monitoring, the system maintains high treatment efficiency while preventing hypotension and intradialytic symptoms through coordinated parameter modification.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If lower filtration rates are used to prevent hypotension and symptoms, then patient safety improves, but treatment duration increases and efficiency decreases

Engineering Contradiction:
Improvepatient safety during dialysisVSAvoiddialysis treatment duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements periodic monitoring and adjustment of filtration rates during dialysis treatment. The system uses periodic weight measurements and blood pressure checks to determine when to adjust the ultrafiltration profile. This periodic action allows the treatment to proceed at higher efficient rates during stable periods while providing safety adjustments when needed, thus balancing patient safety with treatment efficiency and duration.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs preliminary assessment of patient fluid status and predicts the optimal filtration profile before treatment begins. By pre-calculating the required ultrafiltration volume and distributing it appropriately throughout the treatment, the system can maintain higher filtration rates for longer periods while still achieving safe fluid removal, thereby reducing total treatment duration while maintaining patient safety.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2380609B1Devices and controller for controlling of a filtration rate
Publication Date: 2017.06.07 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP2380609B1 patent drawingFigure 1
  • EP2380609B1 patent drawingFigure 2
  • EP2380609B1 patent drawingFigure 3

AI summary

The present invention relates to a method for controlling of a filtration rate during treatment of a body fluid, particularly during haemofiltration or dialysis of a patient by means of a respective device, comprising the steps of defining a target relation, or a development during dialysis thereof, between one or more calculated or measured value(s) reflecting the mass or the concentration or the volume of a substance comprised by a tissue or a bodily fluid of the patient, and one or more calculated or measured value(s) reflecting a distribution space of the patient or an approximation thereof; during dialysis repeatedly calculating or measuring of value(s) reflecting the mass or the concentration or the volume of the substance and/or reflecting the distribution space or an approximation thereof, and determining the relation there between at least once; and controlling the filtration rate of the body fluid treatment device such that the determined relation is or approaches the target relation or aims to do or be so. It also relates to a controller, an apparatus, a device, a digital storage means, a computer program product, and a computer program.