Hemodialysis Dialysate pH-Bicarbonate Feedback Control
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Solution Overview
Problem
Existing hemodialysis systems face challenges in predicting and managing pH and bicarbonate concentration changes due to factors like patient blood urea level, dialysate composition, and sorbent properties, necessitating a need for systems that can control these parameters while minimizing system size and fluid requirements.
Innovation Solution
A dialysate flow loop system with a urea sensor and infusate system to add bicarbonate buffer, controlled by a controller to achieve a predetermined bicarbonate concentration, and a pH-buffer management system to adjust pH and bicarbonate levels using acid or base equivalents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sorbent materials are used to remove urea from dialysate, then urea removal effectiveness is improved, but prediction of pH and bicarbonate concentration becomes difficult
Solution Approach 1:
The system employs pH sensors and bicarbonate sensors that continuously monitor dialysate parameters and feed this information back to the controller. The controller adjusts the infusion rates of acid concentrate and base concentrate to maintain target pH and bicarbonate levels, compensating for unpredictable changes caused by sorbent materials.
Solution Approach 2:
The patent introduces intermediary substances (acid concentrate and base concentrate) that mediate between the unpredictable sorbent-material-induced pH changes and the desired target pH/bicarbonate levels. These concentrates act as adjustable buffers to counteract unwanted pH shifts.
2Adaptability or versatility
If regenerative hemodialysis systems are used, then system versatility is improved, but control of dialysate pH and bicarbonate concentration becomes difficult
Solution Approach 1:
The system uses continuous feedback from pH sensors and bicarbonate sensors to automatically adjust the infusion of acid and base concentrates, making the system easy to operate despite its versatility. The controller processes sensor data and modulates concentrate delivery to maintain precise pH and bicarbonate control.
Solution Approach 2:
The system performs self-adjustment by automatically monitoring its own dialysate parameters and correcting deviations through automated infusion control of acid and base concentrates, reducing the need for manual intervention and simplifying operation.
3Quantity of substance
If bicarbonate buffer is added to dialysate, then bicarbonate concentration is improved, but system complexity increases
Solution Approach 1:
The system segments the bicarbonate delivery function into separate components: a bicarbonate reservoir, a dedicated infusion line, and controlled delivery mechanism. This modular approach manages complexity by organizing the bicarbonate buffer system as a distinct, controllable subsystem.
Solution Approach 2:
The system uses an intermediary infusion system with acid and base concentrates as mediating substances to achieve precise bicarbonate control. Rather than directly adding solid bicarbonate, the system uses soluble concentrate solutions that can be precisely metered and mixed into the dialysate.
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 system effectively maintains predetermined bicarbonate and pH levels in dialysate, ensuring precise patient treatment by dynamically adjusting these parameters based on real-time urea content and pH measurements.
Implementation Method 1
a urea sensor that measures or allows for the calculation of urea content of the dialysate
Implementation Method 2
an infusate system wherein the infusate system can be configured to add a bicarbonate buffer component to the dialysate
Implementation Method 3
a controller for calculating an amount of the bicarbonate buffer component for addition to the dialysate to generate a predetermined total bicarbonate buffer concentration
Implementation Method 4
a dialysate flow loop for circulating a dialysate through a dialyzer wherein acid or base equivalents are added to the dialysate during operation
Implementation Method 5
a pH-buffer management system for adding or generating a pH-buffer modifying solution to the dialysate wherein the pH-buffer management solution has a different pH from the dialysate
Data Source
AI summary
Systems and methods for managing the pH of a dialysate fluid during hemodialysis therapy. The systems and methods adjust dialysate pH and buffer concentration to generate a predetermined total bicarbonate buffer concentration in a dialysate entering a dialyzer. The systems and methods generate a pH-modifying fluid and selectively add the pH modifying fluid to the dialysate in order to accurately control the total bicarbonate buffer concentration in the dialysate entering the dialyzer.