Neck-Worn Sensor for Non-Invasive Heart Failure Monitoring
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Solution Overview
Problem
Current methods for measuring cardiac output (CO) and stroke volume (SV) in congestive heart failure patients are invasive, inaccurate, and impractical for continuous, non-invasive monitoring, especially for ambulatory patients, due to the need for specialized operators and equipment.
Innovation Solution
A necklace-shaped sensor that combines miniaturized impedance-measuring and ECG systems to measure CO, SV, fluid levels, and cardiac arrhythmias, using a wireless transmission system to send data to a cellular device for processing and analysis, with algorithms compensating for motion and activity to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If implanted devices with impedance measurement (OptiVol/CorVue) are used, then fluid status can be monitored, but the system becomes invasive and requires surgical implantation
Solution Approach 1:
The patent replaces the invasive implanted impedance measurement system with a non-invasive external sensor system that uses electrical impedance tomography to measure thoracic fluid status through the chest wall, eliminating the need for surgical implantation while maintaining measurement capability
Solution Approach 2:
The patent introduces an external sensor array as an intermediary between the measurement goal and the patient's body, using surface electrodes and signal processing algorithms to indirectly measure internal fluid status without direct contact with internal tissues
2Measurement precision
If Doppler/ultrasound is used to measure cardiac parameters, then CO and SV can be measured, but specialized operators and equipment are required making it impractical for continuous home monitoring
Solution Approach 1:
The patent creates a self-service monitoring system where the patient independently wears the sensor device and automatically collects cardiac data without requiring trained operators, with the system performing self-calibration and automated analysis
Solution Approach 2:
The patent extracts the complex ultrasound imaging and specialized operator requirements, replacing them with simplified electrical impedance sensors that can be easily operated by patients themselves while maintaining essential measurement capabilities
3Ease of operation
If simple weight scales are used to detect CHF, then the system is easy to use, but the parameter is not sensitive enough to detect early onset of CHF
Solution Approach 1:
The patent changes the measurement parameter from gross weight changes to electrical impedance variations, which are more sensitive to early fluid accumulation, while maintaining ease of use through automatic sensor operation and wireless data transmission
4Measurement precision
If implanted pacemakers with impedance measurement are used, then CO and SV can be calculated, but the device complexity increases and requires surgical implantation
Solution Approach 1:
The patent segments the monitoring function from the pacemaker implant, using a separate external sensor device that communicates wirelessly, thereby distributing system complexity across independent components rather than requiring a complex implanted system
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 sensor provides continuous, non-invasive, and accurate monitoring of cardiovascular parameters, enabling early detection of congestive heart failure and guiding adjustments to diet and medication, reducing hospital readmissions.
Implementation Method 1
measuring an impedance signal from the patient using a pair of impedance electrodes
Implementation Method 2
measuring an ECG signal from the patient using a pair of ECG electrodes
Data Source
AI summary
The invention provides a sensor for measuring both impedance and ECG waveforms that is configured to be worn around a patient's neck. The sensor features 1) an ECG system that includes an analog ECG circuit, in electrical contact with at least two ECG electrodes, that generates an analog ECG waveform; and 2) an impedance system that includes an analog impedance circuit, in electrical contact with at least two (and typically four) impedance electrodes, that generates an analog impedance waveform. Also included in the neck-worn system are a digital processing system featuring a microprocessor, and an analog-to-digital converter. During a measurement, the digital processing system receives and processes the analog ECG and impedance waveforms to measure physiological information from the patient. Finally, a cable that drapes around the patient's neck connects the ECG system, impedance system, and digital processing system.