RF Sensor Calibration for Bioimpedance Thorax Fluid Monitoring
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Solution Overview
Problem
Bio impedance measurements face accuracy, specificity, and stability issues due to the use of electrical currents, limiting their effectiveness in relative and trend analysis for fluid content monitoring in the thorax area.
Innovation Solution
A system and method that utilize radiofrequency (RF) sensors in conjunction with bio impedance measurements to calculate a calibration function, adjusting subsequent bio impedance measurements to improve accuracy and consistency of thorax area values, such as fluid levels, by correlating RF interaction measurements with bio impedance measurements during a learning phase and applying the calibration function during an operational phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical currents are used for bio impedance measurements, then fluid content monitoring capability is provided, but accuracy, specificity and stability issues occur
Solution Approach 1:
The patent introduces RF sensors as an intermediary measurement modality that does not directly contact or stimulate the tissue with electrical currents. The RF sensors measure thorax area changes through electromagnetic field interactions, providing a stable and accurate reference measurement that mediates between the bio impedance measurements and the actual physiological parameters, thereby resolving the reliability and accuracy issues.
Solution Approach 2:
The patent changes the measurement parameter from direct electrical impedance to RF field interaction characteristics. By measuring how RF radiation interacts with the thorax area (reflectivity, absorption, or transmission properties) rather than using electrical currents, the system achieves more stable and accurate measurements that are less susceptible to the harmful effects of electrical current passage through tissue.
2Loss of information
If bio impedance measurements are used for fluid status monitoring, then fluid content information is obtained, but false alerts and reduced reliability occur
Solution Approach 1:
The patent implements a feedback mechanism where RF sensor measurements continuously monitor thorax area changes and provide real-time validation of bio impedance measurements. When RF measurements detect changes consistent with fluid status changes, the system confirms the bio impedance readings; when discrepancies occur, the system can reject false readings, thereby reducing false alerts and improving overall reliability through continuous feedback validation.
Solution Approach 2:
The system performs preliminary calibration by establishing the relationship between RF sensor measurements and bio impedance measurements during a learning phase before actual monitoring begins. This preliminary action creates a calibrated model that accounts for individual patient anatomy and physiology, enabling more accurate and reliable fluid status monitoring while reducing false alerts caused by anatomical variations.
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 integration of RF sensors with bio impedance measurements enhances the accuracy and consistency of fluid level monitoring, reducing false alerts and providing more accurate and quantitative fluid content assessments in the thorax area, including lung fluid levels.
Implementation Method 1
at least one radiofrequency (RF) sensor adapted to measure RF interaction measurements of RF radiation interacting with the target thorax area
Implementation Method 2
The electrical principle behind bio impedance is Ohm's law. When a sinusoidal electrical current passes through a medium, a sinusoidal voltage drop in magnitude is generated.
Implementation Method 3
The electrical resistance gives the relationship between the electrical current and the corresponding voltage. An electrical current that passes through biological tissue is impeded by biological tissue resistance, which causes a phase shift between the sinusoidal electrical current and the sinusoidal voltage.
Data Source
AI summary
A system comprising a plurality of electrodes adapted to measure bio impedance measurements using electrical currents passing in a target thorax area of a target therebetween during a learning phase, at least one radiofrequency (RF) sensor adapted to measure RF interaction measurements of RF radiation interacting with the target thorax area during the learning phase, and at least one processor adapted to: calculate calibration function according to the bio impedance measurements and the RF interaction measurements, and determine a target thorax area value by adjusting subsequent bio impedance measurements using subsequent electrical currents passing in the target thorax area during an operational learning phase using the calibration function.