A Wireless Portable System With Few Electrodes Using Thoracic Electrical Signals for Long-Term and Real-Time Hemodynamic Monitoring

Abstract

Continuous, long-term hemodynamic monitoring is crucial for enhancing the prevention and diagnosis of cardiovascular diseases (CVDs). This study introduces a system that extracts impedance cardiography (ICG), electrocardiography (ECG), and respiratory (RESP) signals from thoracic electrical signals using only four electrodes. A wireless, portable hemodynamic monitoring system has been developed, capable of acquiring multimodal physiological signals, including ICG, ECG, and photoplethysmography (PPG), among others. A signal processing approach was developed, combining the timefrequency characteristics and temporal correlations of the signals. This method includes signal denoising and locating characteristic points, enabling the real-time calculation of hemodynamic parameters such as cardiac output (CO). Furthermore, an artificial neural network is constructed based on various features extracted from the multimodal physiological signals to estimate blood pressure (BP). The device measures $85\times 48\times 18$ mm, weighs 76 g, and consumes 260 mW of power. It can operate continuously for at least 24 h. When compared to a commercial bedside hemodynamic monitoring device, the consistency of the key measured hemodynamic parameters is relatively high. The system shows promising applications in diagnosing CVDs and managing chronic cardiovascular conditions.