Low Cost Non-İnvasive Portable Monitor Platform for Cardiac Biopotential and Transthoracic Impedance Measurements

Purpose Simultaneous monitoring of ECG and thoracic electrical bioimpedance (TEB) is important in evaluating cardiovascular performance. TEB is a non-invasive technique based on measuring the impedance value that changes in the chest area depending on the heartbeat. Within the framework of this study, it can be used in home monitoring and biotelemetry applications to measure thoracic electrical bioimpedance (TEB), ECG and ICG. Methods Within the scope of this study, a four-electrode TEB measurement system was designed and built using the Raspberry Pi single board computer and its original monitor, ESP32 and EVAL-ADAS1000SDZ evaluation board. With the designed system, ECG and thoracic impedance measurements at 50 kHz current frequency were taken as real-time over a single channel. Delta_Z and ICG signals were created from thoracic impedance values with the developed software.ResultsWhile the thoracic impedance value varies between 15-45 Ω, the 67 thoracic impedance value measured with the designed system is approximately 1000 times the 68 reference value. The impedance change in the thoracic region was measured with the designed 69 system between 0.1-0.2 Ω values, and the compatibility of these values with reference values was 70 determined. While the reference value of the dZ / dt signal is 0.8 - 3.5 Ω / s, this value is between 2.3 - 71 5.3 Ω / s in the measurements taken with the designed system.Conclusion The prototype is achieved in detecting small changes in the thoracic impedance signal. The prototype is cheap, portable, small-sized and medically safe, so it is suitable for home care services and clinics. In addition, the developed system can be adapted to wearable technology. In order to increase the success of the system, the impedances values added to the thoracic impedance value should be determined and a calibration procedure should be established.