Non-Invasive Optical Sensor for Blood Volume and Sodium Monitoring
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Solution Overview
Problem
Current methods for monitoring blood parameters during extracorporeal blood treatments, such as hemodialysis, are invasive, costly, and lack accuracy, particularly for real-time measurement of relative blood volume variation (ΔRBV) and plasma sodium concentration (Napl), which are crucial for optimizing treatment efficacy and patient safety.
Innovation Solution
A non-invasive sensor system that uses multiple detectors and a controller to determine blood volume variation and plasma sodium concentration by analyzing light signals transmitted through the blood, employing state-space mathematical modeling and Kalman filtering to provide continuous, accurate measurements without the need for blood sampling or perturbation of the dialysate circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods are used to measure blood parameters, then measurement precision may be improved, but ease of operation deteriorates and loss of time increases
Solution Approach 1:
The patent replaces invasive mechanical blood sampling with non-invasive optical measurement. The sensor system uses light sources and detectors to measure blood parameters (ΔRBV, Napl) through the skin and extracorporeal circuit without requiring blood draws, thereby maintaining measurement precision while dramatically improving ease of operation and eliminating procedural complexity
Solution Approach 2:
The patent introduces an optical intermediary system consisting of light sources, detectors, and mathematical modeling (state-space models with Kalman filtering) that mediates between the blood parameters and the measurement device. This intermediary optical system enables accurate non-invasive measurement by converting biological parameters into detectable optical signals
2Measurement precision
If blood sampling is performed frequently, then measurement precision improves, but loss of time increases and productivity decreases
Solution Approach 1:
The patent implements continuous real-time monitoring of blood parameters throughout the treatment session. The sensor system continuously measures ΔRBV and Napl without interruption, eliminating the need for discrete sampling events. This continuous measurement approach maintains high measurement precision while maximizing treatment productivity by eliminating time lost to repeated blood draws and laboratory analysis
3Measurement precision
If complex measurement systems are used, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent replaces complex invasive measurement systems with a simpler non-invasive optical system. By using light-based measurement through the skin and extracorporeal circuit, the system achieves accurate blood parameter measurement without complex blood sampling infrastructure, laboratory equipment, or invasive catheters, thereby reducing overall device complexity while maintaining precision
4Measurement precision
If invasive measurement methods are used, then measurement precision may be improved, but object-affected harmful factors increase
Solution Approach 1:
The patent substitutes invasive mechanical blood sampling with non-invasive optical measurement, thereby eliminating harmful factors associated with needle sticks, infection risk, blood loss, and patient discomfort. The optical sensor system measures blood parameters through the skin and extracorporeal circuit without penetrating the body, completely removing these harmful effects while maintaining measurement precision
Solution Approach 2:
The patent enables the measurement system to function without requiring blood extraction or laboratory processing. The optical sensor system performs self-contained measurement of blood parameters directly at the patient site, eliminating the need for external laboratory services and reducing associated risks and harms
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 real-time, accurate monitoring of ΔRBV and Napl, allowing for improved treatment optimization and patient safety by providing continuous, non-invasive, and cost-effective measurement of blood parameters during extracorporeal treatments.
Implementation Method 1
uses multiple detectors and a controller to determine blood volume variation and plasma sodium concentration by analyzing light signals transmitted through the blood
Data Source
AI summary
An apparatus for extracorporeal treatment of blood comprising a treatment unit, a blood withdrawal line, a blood return line, a preparation line and a spent dialysate line; a non-invasive blood volume sensor for determining an additional property of blood is active on a tube segment of the blood withdrawal line or of the blood return line; the sensor includes one source for directing a signal towards the blood, a plurality of detectors for receiving the signal, and a controller receiving the output signals from the detectors and determining a blood volume variation and a value of sodium concentration in the blood (NaPl) both based on the output signals. A process of determining at least one parameter and on property of blood circulating an extracorporeal blood circuit is also disclosed.