RF Hemodynamic Monitoring Using Through-Body Signal Modulation
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Solution Overview
Problem
Existing RF systems struggle to accurately determine physiological information due to insufficient or unclear return signals, particularly in non-invasive hemodynamic monitoring.
Innovation Solution
A non-invasive hemodynamic monitoring system (NIHMS) using ultra-wide band RF signals with optimized transmitters and receivers, positioned on the body to capture signal modulation from heart and vasculature interactions, processes these signals in the frequency domain to estimate cardiac parameters like volumetric flow output rate and ejection fraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RF systems are used for non-invasive monitoring, then the system complexity is reduced, but the measurement precision and reliability of physiological parameters deteriorate due to insufficient or unclear return signals
Solution Approach 1:
The system segments the RF signal processing into multiple components: transmitted signal generation, signal propagation through tissue, interaction with blood volume, and received signal detection. By analyzing different segments of the signal path and applying specific processing techniques to each, the system achieves precise physiological parameter measurement without requiring overly complex integrated hardware
Solution Approach 2:
The system changes the frequency parameter of the RF signal to optimize penetration through tissue and interaction with blood volume. By adjusting the frequency characteristics and analyzing frequency-domain representations of the received signals, the system extracts physiological information with high precision while maintaining manageable system complexity
2Measurement precision
If invasive measures like Swan-Ganz catheterization are used, then the measurement precision of hemodynamic parameters is improved, but the harm to the patient increases
Solution Approach 1:
The system replaces mechanical invasive measurement devices (catheters, sensors inserted into blood vessels) with non-invasive RF electromagnetic field-based measurement. The RF signals interact with the blood volume and tissue dielectric properties to provide hemodynamic information without physical intrusion, eliminating the harmful effects of invasive procedures while maintaining measurement precision
Solution Approach 2:
The system uses RF electromagnetic waves as an intermediary to indirectly measure hemodynamic parameters. Instead of directly contacting the blood flow with sensors, the RF signals serve as a mediator that interacts with the blood volume and tissue properties, allowing precise measurement of physiological parameters without direct mechanical contact or invasion
3Ease of operation
If RF signals are transmitted through the body to detect physiological information, then non-invasive monitoring is achieved, but the return signals become insufficient or unclear due to signal attenuation and tissue interference
Solution Approach 1:
The system employs periodic transmission of RF signals at controlled intervals and uses synchronized detection to extract physiological information. By transmitting signals periodically and analyzing the time-domain and frequency-domain characteristics of the periodic returns, the system maintains signal clarity despite tissue attenuation and interference
Solution Approach 2:
The system applies preliminary signal processing techniques including filtering, amplification, and frequency-domain transformation to the received RF signals before physiological parameter extraction. This preliminary processing enhances the clarity of the return signals by removing noise and interference components introduced by tissue attenuation, preserving the physiological information
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, continuous monitoring of hemodynamic variations, providing diagnostic indicators of cardiac performance without invasive measures, suitable for patient hospital or home monitoring.
Implementation Method 1
an RF transmitting antenna configured for transmitting at least one transmitted RF signal toward the subject and an RF receiving antenna configured for receiving at least one received RF signal transmitted by the RF transmitting antenna and modified by a subject's body
Implementation Method 2
The reflection may occur at the boundary between an organ and tissue. The reflected signals are acquired as return signals
Implementation Method 3
a portion of the transmitted energy reacts in response to the heart's blood content, blood content in the vasculature, tissue thickness and composition, etc. (i.e., body composition); this is due to the specific dielectric properties of blood when contained in a region of heart. In some embodiments, the heart's blood volume can be understood as acting as a transfer function that refracts the transmitted wave
Implementation Method 4
Such interactions between the RF waveforms and the internal structures of the subject may include reflection, refraction, scattering, or otherwise changing or attenuating the RF waveforms
Implementation Method 5
the nature of signal attenuation of the transmitted signal. For example, with the inventive technology, a portion of the transmitted energy reacts in response to the heart's blood content
Data Source
AI summary
Hemodynamic monitoring system is presented. In one embodiment, a system for non-invasive monitoring of a subject's heart includes an RF transmitting antenna. The RF transmitting antenna is configured for transmitting at least one transmitted RF signal toward the subject. The system also includes an RF receiving antenna. The RF receiving antenna is configured for receiving at least one received RF signal transmitted by the RF transmitting antenna and modified by a subject's body. The RF transmitting antenna and the RF receiving antenna are located on opposing sides of a planar projection of the subject's heart. The system also includes a processing circuit configured for: controlling transmitting and receiving of the RF signal, and determining, based on the at least one received RF signal, at least one physiological parameter of the subject.