Renal Replacement Fluid Mixing Using Scale-Based Composition Control
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Solution Overview
Problem
Current renal replacement therapy (RRT) systems consume large quantities of medical fluid, leading to environmental impact and operational challenges, particularly in acute kidney injury (AKI) treatments where existing machines lack on-line fluid generation capabilities without requiring replacement.
Innovation Solution
A method and system for generating medical fluid on-line in RRT systems, utilizing a control device to manage pumps and scales, ensuring precise mixing of constituent fluids based on weight changes measured by scales, thereby eliminating the need for continuous CRP sensor feedback during fluid generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If on-line fluid generation is implemented in AKI machines, then environmental impact and operational burden are reduced, but existing AKI machines lack the necessary capability and would require replacement
Solution Approach 1:
The control device is designed to perform multiple functions: it can operate in a first mode using CRP sensor feedback for composition control, and in a second mode using scale-based weight change monitoring for mixing control. This multi-functionality allows existing AKI machines to gain on-line fluid generation capability without replacement, while reducing environmental impact through concentrated fluid delivery
2Manufacturing precision
If CRP sensor feedback is continuously used for fluid composition control, then mixing precision is maintained, but sensor life is reduced and costs increase
Solution Approach 1:
The system dynamically switches between two control modes: initially using CRP sensor feedback for precise composition control, then transitioning to scale-based weight change monitoring. This dynamic operation reduces continuous sensor exposure to harsh fluid environments while maintaining composition precision through alternative measurement of weight changes that correlate with composition
Solution Approach 2:
The system implements a dual feedback mechanism: CRP sensor feedback for initial composition control, and scale feedback based on weight changes for ongoing mixing control. The scale feedback provides continuous monitoring without the wear and contamination issues of continuous CRP sensor use, thereby extending sensor life while maintaining precision
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 efficient on-line generation of medical fluid, reducing environmental impact and operational burdens, while extending the life of CRP sensors and potentially allowing the use of permanently installed sensors, thereby lowering costs and improving treatment efficiency.
Implementation Method 1
a first scale (2a) to which the first container (3a) is arrangeable, a second scale (2b) to which the second container (3b) is arrangeable
Implementation Method 2
a first pump (P1) arranged to convey the first fluid (F1) from the first container (3a} into the supply path (4a)
Data Source
AI summary
A system for generating a medical fluid for renal replacement therapy is operated by a control device according to a method. In the method, a first pump is operated to convey a first fluid from a first container, arranged on a first scale, into a supply path, and a second pump is operated to convey a second fluid from a second container, arranged on a second scale, into the supply path, to generate a mixture therein. The speed of at least one of the pumps is adjusted until a sensor measures a target value of a composition-related parameter. A relation between weight changes of the first and second scales is determined while the sensor measures the target value. The medical fluid is then generated in the supply path, by the pumps being operated, based on signals from the scales, to achieve said relation.