Dialysis Absorption Measurement Stabilization

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Solution Overview

Problem

Existing renal replacement therapy devices face challenges in providing reliable and accurate Kt/V value and reduction rate measurements due to varying radiation intensity and detector sensitivity over time, leading to falsified absorption measurements.

Innovation Solution

The device compensates for radiation intensity changes by tracking and adjusting the radiation source's intensity and incorporates temperature control to stabilize the signal, using a control loop and two photodetectors for precise absorption measurements, ensuring consistent radiation and detector sensitivity throughout the treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If absorption measurement is performed using a radiation source and detector system during renal replacement treatment, then Kt/V value and reduction rate can be determined, but the radiation intensity of the source and sensitivity of the detector vary over time causing measurement falsification

Engineering Contradiction:
Improveabsorption measurement accuracyVSAvoidmeasurement consistency over time
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The device measures the radiation intensity at the detector position using a reference photodetector that receives radiation without absorption by dialysis fluid. This measured intensity is fed back to a control unit, which adjusts the radiation source intensity to maintain a constant target value, thereby compensating for source aging and detector sensitivity variations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

A reference photodetector is introduced as an intermediary element to measure the actual radiation intensity reaching the detector position. This reference measurement serves as a mediator between the radiation source and the absorption measurement, enabling indirect monitoring and compensation of intensity variations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If the radiation source operates over extended periods, then treatment duration is sufficient, but the radiation intensity decreases due to aging

Engineering Contradiction:
Improveoperating timeVSAvoidradiation intensity
Core Design Contradiction:
Duration of action of moving objectVSIllumination intensity

Solution Approach 1:

The control unit continuously monitors the radiation intensity at the detector position and adjusts the radiation source intensity in real-time based on feedback signals, compensating for aging effects and maintaining consistent measurement conditions throughout the treatment duration

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the operating parameters of the radiation source, specifically adjusting its intensity output based on measured deviations from the target value, thereby maintaining optimal radiation intensity despite source aging over extended operating periods

Inventive Principle:
Principle #35Parameter changes

3Temperature

If temperature fluctuations occur during treatment, then environmental conditions vary, but the detector sensitivity and radiation source intensity become unstable

Engineering Contradiction:
Improveambient temperatureVSAvoidsignal stability
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The system compensates for temperature-induced parameter changes by dynamically adjusting the radiation source intensity and detector sensitivity settings based on the measured target value, maintaining stable measurement conditions despite ambient temperature fluctuations

Inventive Principle:
Principle #35Parameter changes

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

This approach provides reliable and unbiased Kt/V value and reduction rate measurements by normalizing absorption measurements and stabilizing signal intensity, significantly improving the accuracy and informative value of the results.

Implementation Method 1

The dialysis fluid contains different salts in such a concentration that the waste products, including toxic substances, are carried through the membrane from the patient's blood to the dialysis fluid by diffusion and convection... absorption measurement in the used dialysis fluid

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Implementation Method 2

the waste products, including toxic substances, are carried through the membrane from the patient's blood to the dialysis fluid by diffusion and convection

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

the waste products, including toxic substances, are carried through the membrane from the patient's blood to the dialysis fluid by diffusion and convection

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2218472B2Device for treating blood outside the body
Publication Date: 2022.03.16 B BRAUN AVITUM
  • EP2218472B2 patent drawingFigure 1
  • EP2218472B2 patent drawingFigure 2
  • EP2218472B2 patent drawing

AI summary

The apparatus has a measuring device provided within a discharge unit (30) for determining absorption of used dialysis fluid flowing through the discharge unit. The measuring device includes a radiation source (41) for monochromatic electromagnetic radiation, and a detector system (42) detects intensity of the electromagnetic radiation. A compensation unit (50) compensates changes that occur in intensity of the electromagnetic radiation of the radiation source and/or sensitivity of the detector system, and is formed as a temperature regulator. An independent claim is also included for a method for compensating intensity changes of an electromagnetic radiation source.