Dialysis Fluid Sodium Balancing with Urophanic Interference Correction
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Solution Overview
Problem
Existing dialysis technologies struggle to accurately adjust the sodium concentration in dialysis fluid to match individual patient needs, leading to undesirable changes in plasma sodium concentration and associated health risks, due to interference from urophanic substances affecting conductivity measurements.
Innovation Solution
A device and method that uses conductivity and optical sensors to measure fresh and used dialysis fluid, along with a control unit to adjust the sodium concentration in real-time, accounting for urophanic substance loading, enabling precise sodium balancing and isonatremic dialysis without requiring patient blood samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conductivity probes are used to control dialysis fluid composition, then proportioning can be automated, but measurement precision deteriorates due to interference from urophanic substances
Solution Approach 1:
The patent introduces an intermediary correction approach by detecting urophanic substances separately and using their measured concentration to mathematically correct the conductivity measurement. This intermediary detection allows the system to compensate for the interference rather than being directly affected by it, maintaining both automation and measurement precision.
2Reliability
If sodium concentration in dialysis fluid is increased to treat blood pressure drops, then patient well-being improves, but water intake increases requiring higher ultrafiltration rates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors conductivity (and by extension sodium concentration) and adjusts the dialysis fluid composition in real-time. This allows precise maintenance of target sodium levels, avoiding both excessive sodium (which would increase water intake) and insufficient sodium (which would cause blood pressure drops), thereby resolving the contradiction between patient well-being and ultrafiltration requirements.
3Device complexity
If standardized dialysis fluid composition is used, then device complexity is reduced, but adaptability to individual patient needs deteriorates
Solution Approach 1:
The patent enables the dialysis system to automatically adjust its own operation by continuously measuring conductivity and urophanic substances, calculating the required composition adjustments, and implementing them without external intervention. This self-service capability provides individualized patient care while maintaining relatively simple device architecture, as the system adapts automatically rather than requiring complex pre-programming for each patient.
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
Achieves accurate sodium balancing during dialysis, reducing ultrafiltration rates and minimizing health risks, allowing for patient-specific treatment without additional equipment or interruptions.
Implementation Method 1
The conductivities of a fresh dialysis fluid supplied to the dialyzer and of a used dialysis fluid discharged from the dialyzer are detected
Implementation Method 2
a third measuring apparatus provided in the discharge line for measuring or estimating a loading of the used dialysis fluid with urophanic substances
Implementation Method 3
the blood of a patient is passed through a dialyzer through which a dialysis fluid is passed at the same time. In the dialyzer, blood and dialysis fluid are brought into contact via a semi-permeable membrane so that an exchange of substances can take place
Implementation Method 4
patients are dependent on keeping their water and sodium intake to a minimum. Sodium is particularly absorbed in the form of common salt (NaCl). A dialysis patient compensates for increased sodium intake by drinking a corresponding amount of liquid. However, increased liquid intake means that more excess liquid must be removed from the patient by ultrafiltration during the next dialysis treatment
Data Source
AI summary
A device and method for extracorporeal blood treatment, in particular for hemodialysis, and a method for the balance control of a dialysis fluid in an extracorporeal blood treatment. Sodium balancing can be implemented with improved accuracy during the blood treatment, because distorting effects in the conductivity measurement of the used dialysis fluid can be corrected by taking into account the loading of the used dialysis fluid with urophanic substances, which loading is sensed by an additional measuring apparatus.