[Unconstrained Cardiac Output Measurement System Based on Thoracic Electrical Impedance Method]

Area of Science:

• Biomedical Engineering
• Medical Devices
• Electrical Engineering

Background:

• Cardiac output monitoring is crucial for assessing cardiovascular function.
• Existing methods for cardiac output measurement can be invasive or complex.
• Development of non-invasive, accurate cardiac output detection systems is needed.

Purpose of the Study:

• To develop an unconstrained cardiac output detection system using the thoracic electrical impedance (TEI) method.
• To integrate embedded technology for signal generation and impedance measurement.
• To validate the system's performance through comparative experiments.

Main Methods:

• Utilized a PIC embedded microcontroller (PIC18F4520) with Pulse Width Modulation (PWM) function.
• Generated a 50 kHz, 2 mA_rms constant current sinusoidal excitation signal.
• Applied the signal via electrodes on the ears and lower abdomen, measuring TEI across the thorax.

Main Results:

• The developed system successfully measured thoracic electrical impedance.
• Comparative experiments demonstrated good consistency between the TEI method and the dye dilution method.
• The system provides a viable non-invasive approach for cardiac output estimation.

Conclusions:

• The developed unconstrained cardiac output detection system is effective.
• The integration of embedded technology and TEI method offers a promising solution for cardiac monitoring.
• Further research can explore clinical applications and system refinements.