Dialysis Sodium Control Using Plasma Conductivity Feedback
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Solution Overview
Problem
Existing extracorporeal blood treatment systems lack individualized sodium concentration control, leading to deviations in patient fluid balance and requiring expensive and labor-intensive laboratory tests or operator estimation.
Innovation Solution
An apparatus with sensors and a control unit that continuously monitors and adjusts plasma conductivity and sodium concentration during treatment, using real-time data to maintain target values and reduce operator workload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sodium concentration prescription is set independently of pre-dialysis serum sodium levels, then the dialysis treatment can be performed with standardized protocols, but patient fluid balance control deteriorates and individualization is lost
Solution Approach 1:
The system dynamically changes the sodium concentration parameter in dialysis fluid based on real-time measurements of plasma sodium concentration and conductivity. The control unit adjusts the sodium concentration prescription from a fixed value to a variable parameter that adapts to the patient's actual physiological state, resolving the contradiction between standardized protocols and individualized control
Solution Approach 2:
The system implements a feedback loop where sensors continuously measure plasma sodium concentration and conductivity, and the control unit uses this feedback information to adjust the sodium concentration in dialysis fluid. This closed-loop control ensures reliable fluid balance management while maintaining operational simplicity
2Reliability
If sodium concentration prescription is set based on monthly laboratory tests, then individualization can be achieved, but treatment cost increases and time loss between adjustments occurs
Solution Approach 1:
The system replaces discrete monthly laboratory measurements with continuous real-time monitoring of plasma sodium concentration and conductivity during each dialysis treatment. This continuous measurement approach eliminates time loss between adjustments and provides up-to-date individualized treatment parameters
Solution Approach 2:
The system substitutes expensive laboratory testing with in-line electrical conductivity measurement and optical detection methods. This replacement provides continuous individualized sodium concentration data without the time loss and cost associated with traditional laboratory analysis
3Measurement precision
If dedicated disposable components or additional work are used to estimate initial patient sodium, then measurement accuracy can be improved, but device complexity and operator workload increase
Solution Approach 1:
The system uses the existing dialysis circuit and standard sensors to perform multiple functions: dialysis treatment, plasma sodium concentration measurement, and conductivity measurement. This multi-functional approach achieves precise initial sodium measurement without requiring dedicated disposable components or additional equipment
Solution Approach 2:
The system automatically measures and calculates initial plasma sodium concentration using the dialysis fluid conductivity data and standard physiological relationships. This self-service measurement eliminates the need for operator estimation or manual laboratory testing, reducing both workload and complexity
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
The apparatus ensures accurate and efficient regulation of plasma conductivity and sodium concentration, improving patient comfort and treatment efficacy while reducing the need for costly and frequent laboratory tests.
Implementation Method 1
at least one treatment unit (for example a dialyser or a filter or ultrafilter or a plasma filter or a filtering unit of another type) having a semipermeable membrane which separates the treatment unit into two chambers
Implementation Method 2
a third parameter (Cd, Na) relating to a conductivity or concentration of a liquid crossing the dialysis line and/or the infusion line
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control unit of an apparatus for extracorporeal blood treatment is configured to perform a control procedure comprising: calculating parameter control values to be set during a time interval after the instant in which the control is made, on the basis of actual values and of prescription values of variation in blood volume, ultrafiltration flow rate, concentration of sodium; imposing the parameter control values during the time interval consecutive to the instant in which the control is made such that the actual values of the variation in blood volume track the prescription values of the variation in blood volume over a predetermined treatment time. The control unit is further configured to perform a procedure for automatically estimating/calculating a target plasma conductivity and/or a target concentration of sodium in plasma to be reached at the end of the extracorporeal blood treatment.