Dialysis Recirculation Detection via Transient Flow Analysis

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Solution Overview

Problem

Current methods for detecting recirculation in arteriovenous shunts during hemodialysis are prone to external influences, require expensive equipment, and involve complex procedures such as bolus injections, which can be risky and costly, limiting their effectiveness and practicality for continuous monitoring.

Innovation Solution

A method and device that utilize a dialysis machine to detect recirculation by measuring changes in physico-chemical parameters, such as UV absorption, through a sensor on the dialysate side, without the need for bolus injections, using a dialysis fluid pump to adjust blood flow and detect recirculation based on transient behavior analysis, allowing for continuous and automatic monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If bolus injection methods are used to detect recirculation, then measurement precision can be improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improverecirculation detection accuracyVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the recirculation detection function from complex external monitoring equipment and integrates it into the existing dialysis machine's control system. By utilizing the dialysis machine's existing sensors and control capabilities, the invention eliminates the need for separate expensive monitoring devices while maintaining detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The dialysis machine's control system is designed to perform multiple functions: it manages the dialysis treatment itself and simultaneously detects recirculation by analyzing parameter changes during the treatment. This multi-functionality eliminates the need for separate dedicated recirculation monitoring equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If bolus injection methods are used for recirculation detection, then measurement precision improves, but the procedure becomes more risky and costly

Engineering Contradiction:
Improverecirculation detection accuracyVSAvoidprocedure safety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system uses the dialysis machine's own operational parameters and existing sensors to detect recirculation, rather than requiring external bolus injections. The control system analyzes changes in dialysis parameters that naturally occur during treatment, making the detection process inherently safer and eliminating the risks associated with additional substance injections.

Inventive Principle:
Principle #25Self-service

3Reliability

If continuous monitoring is implemented, then reliability of recirculation detection improves, but device complexity increases

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system continuously monitors dialysis parameters throughout the treatment process, enabling real-time detection of recirculation events. This continuous monitoring is integrated into the existing dialysis treatment workflow, allowing the system to detect recirculation without interrupting or extending the treatment duration.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The control system continuously analyzes dialysis parameters and provides feedback about recirculation status. When recirculation is detected, the system can alert the operator or adjust treatment parameters, creating a closed-loop monitoring system that improves reliability without requiring complex additional hardware.

Inventive Principle:
Principle #23Feedback

4Ease of operation

If automated recirculation detection is implemented, then ease of operation improves, but device complexity increases

Engineering Contradiction:
Improveautomated detection capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The dialysis machine's control system automatically performs recirculation detection using its existing sensors and processing capabilities. The system self-monitors its own operational parameters and automatically identifies recirculation events without requiring external specialized equipment or manual intervention, simplifying the operator's task while utilizing integrated functionality.

Inventive Principle:
Principle #25Self-service

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

Enables reliable, quantitative, and qualitative detection of recirculation with reduced equipment costs and risk, providing continuous monitoring and accurate results without influencing the blood side, thus improving dialysis effectiveness and patient safety.

Implementation Method 1

measuring changes in physico-chemical parameters, such as UV absorption, through a sensor on the dialysate side

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Implementation Method 2

remove uremic toxins by diffusion across the semipermeable membrane from the extracorporeally conducted blood

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2783715B1Method for detecting recirculation in an arteriovenous shunt during ongoing haemodialysis and dialysis system
Publication Date: 2017.05.10 B BRAUN AVITUM
  • EP2783715B1 patent drawingFigure 1~2
  • EP2783715B1 patent drawingFigure 3
  • EP2783715B1 patent drawingFigure 4

AI summary

The control method involves setting a desired blood flow value, at which the recirculation is adjusted and the parameter detected by a sensor (6) adopts an appropriate value. The blood flow value is changed to another lower blood flow value, where a new parameter value is appropriately provided and detected at the sensor. The recirculation is determined based on the course of change or the change from the former parameter value to the latter parameter value. An independent claim is included for a dialysis machine with pressure sensors.