Neck-Worn ECG and Impedance Sensor for Continuous CHF Monitoring
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Solution Overview
Problem
Existing methods for measuring cardiac output (CO) and stroke volume (SV) in congestive heart failure (CHF) patients are invasive, inaccurate, or impractical for continuous monitoring, and existing non-invasive methods are bulky and not widely accepted.
Innovation Solution
A necklace-shaped sensor that measures CO, SV, fluid levels, ECG waveforms, and other parameters using miniaturized impedance and ECG systems, transmitting data wirelessly for continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods (implanted devices, catheters) are used to measure CO and SV, then measurement precision is improved, but patient comfort and ease of operation deteriorate
Solution Approach 1:
The patent replaces invasive mechanical measurement systems (catheters, implanted devices) with non-invasive electrical impedance measurement systems. The impedance-based measurement technique uses external electrodes and electrical signals to measure CO and SV without physical intrusion into the body, thereby maintaining measurement precision while dramatically improving patient comfort and ease of operation.
Solution Approach 2:
The patent introduces electrical impedance as an intermediary measurement parameter. Instead of directly measuring blood volume or flow through invasive means, the system measures electrical impedance changes in the thoracic cavity, which correlate with CO and SV. This intermediary approach enables non-invasive measurement while maintaining clinical accuracy.
2Ease of operation
If non-invasive impedance methods are used, then patient comfort is improved, but measurement precision and clinical acceptance deteriorate
Solution Approach 1:
The patent performs preliminary calibration and validation of the impedance measurement system against gold-standard invasive methods. By establishing correlation equations and calibration protocols before clinical use, the system ensures that non-invasive impedance measurements achieve clinical-grade precision for CO and SV, thereby gaining clinical acceptance while maintaining patient comfort.
Solution Approach 2:
The patent transforms the raw electrical impedance signal into clinically meaningful CO and SV parameters through mathematical modeling and signal processing. By changing the parameter representation from electrical impedance to hemodynamic parameters, the system maintains measurement precision comparable to invasive methods while preserving the non-invasive advantage.
3Reliability
If continuous monitoring is implemented, then early detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements continuous impedance measurement and monitoring, allowing real-time tracking of CO, SV, and thoracic fluid status. This continuous action enables early detection of CHF exacerbations by identifying trends and anomalies in hemodynamic parameters over time, improving reliability while managing system complexity through efficient signal processing and algorithms.
Solution Approach 2:
The patent incorporates feedback mechanisms where continuous impedance measurements are processed to generate real-time information about patient status. This feedback loop enables early warning systems that can detect deteriorating conditions before clinical symptoms manifest, improving early detection capability while using computational feedback to manage system complexity.
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
Provides accurate, continuous, and non-invasive monitoring of cardiovascular parameters, enabling early detection of CHF and improving patient compliance through a comfortable, ambulatory design.
Implementation Method 1
measuring an impedance of the patient between a first pair of electrodes
Implementation Method 2
measuring an electrocardiography (ECG) waveform representing an electrical potential between a second pair of 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.