Dialyzer Clogging Detection via Pressure and UV Absorbance
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Solution Overview
Problem
Current methods for detecting clogging in dialyzers during extracorporeal blood purification are inadequate as they either fail to detect issues in real-time without interrupting treatment or provide inaccurate readings, relying on sodium clearance measurements that are not precise and can be influenced by environmental factors.
Innovation Solution
A method that combines pressure measurements on the blood side with UV absorbance measurements of urinary substances in the dialysate outflow to detect clogging by calculating a baseline and tolerance ranges, allowing for early and accurate identification of clotting without disrupting the dialysis process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If sodium clearance measurements are used to detect clogging, then detection capability is provided, but measurement precision deteriorates due to environmental factors and approximation errors
Solution Approach 1:
The patent replaces the chemical/conductivity-based sodium clearance measurement method with a UV spectroscopy-based measurement system. The UV measuring device measures the absorbance of urinary substances (urea, creatinine) in the dialysate outflow at specific wavelengths (200-400nm), providing direct and accurate measurement of dialysis efficiency without the approximation errors and environmental sensitivity of conductivity measurements.
2Measurement precision
If treatment is interrupted to measure sodium clearance, then dialysis efficiency can be determined, but productivity deteriorates due to treatment interruption
Solution Approach 1:
The patent implements continuous monitoring of dialysis efficiency by continuously measuring the UV absorbance of urinary substances in the dialysate outflow throughout the treatment. This eliminates the need to interrupt treatment for periodic sodium clearance measurements, allowing uninterrupted dialysis while providing real-time detection of dialyzer performance and clogging events.
3Device complexity
If pressure measurement alone is used to detect clogging, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish clogging from other pressure changes
Solution Approach 1:
The patent combines two measurement approaches: pressure measurement in the blood circuit and UV absorbance measurement of urinary substances in the dialysate outflow. By merging these two independent measurement systems, the patent achieves both simple device operation and high measurement precision, as the UV measurement specifically targets dialysis efficiency while pressure measurement provides complementary information about blood flow conditions.
4Measurement precision
If UV absorbance measurement is implemented, then measurement precision improves for dialysis efficiency, but device complexity increases due to additional measurement system
Solution Approach 1:
The UV measuring device serves multiple functions: it measures the absorbance of urinary substances (urea, creatinine) to determine dialysis efficiency, detects clogging events, and provides continuous monitoring throughout treatment. This multi-functionality justifies the addition of the UV measurement system, as it replaces multiple separate measurement systems (periodic sodium clearance measurements, continuous pressure monitoring) with a single integrated UV spectroscopy device.
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 continuous monitoring and early detection of dialyzer clogging, reducing the risk of treatment interruption and improving dialysis efficiency by correlating pressure and UV absorbance data to accurately identify changes in filter performance.
Implementation Method 1
a UV measuring device in the dialysate outflow determines the absorbance of at least one urinary substance
Implementation Method 2
at least one pressure sensor is arranged on the blood side in order to determine the pressure in the blood circuit
Implementation Method 3
The blood is cleaned by diffusive and convective substance transport between the dialysate and the blood side
Implementation Method 4
At the same time, liquid is withdrawn from the patient during convective substance transport due to negative pressure on the dialysis liquid side
Data Source
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AI summary
Detecting performance of dialyzer in a device, involves measuring pressure of dialyzate in blood side of at least one pressure sensor, measuring UV absorbance of at least one uremic substance from predefined number (n) of measured pressure values ??(Px), calculating base line compensation line, calculating tolerance range, and detecting whether the measured UV absorbance is within the calculated range of tolerance. Method for detecting performance of dialyzer in a device for extracorporeal cleaning of blood, involves measuring pressure of dialyzate in blood side of at least one pressure sensor, measuring UV absorbance of at least one uremic substance from predefined number (n) of measured pressure values ??(Px), where x is number of pressure measurements, calculating base line compensation line, calculating tolerance range for the measured UV absorbances from a predefined number (m) of measured UV absorbances (Ay) by extrapolating a future UV absorbance (Ay+1 (calculated)), where y is the number of UV measurements and it is determined if the measured pressure value (P) is within the calculated range of tolerance about the base line, and detecting whether the measured UV absorbance (Ay+1 (measured)) is within the calculated range of tolerance for the calculated UV absorbance (Ay+1 (calculated)) , where performance is detected when the measured pressure value (P) lies outside the calculated tolerance area around the base line, and the measured UV absorbance (Ay+1) out of the calculated tolerance zone for the calculated UV absorbance. An independent claim is included for device for extracorporeal cleaning of blood.