tailieunhanh - A new method of measuring impedance cardiography for cardiac output estimation by directly digitizing the high frequency modulated signal at lower sampling rate

Cardiac output (CO) is an important hemodynamic index to assess the heart condition of the patients. Impedance cardiography (ICG) is an advanced method that can noninvasively and continuously monitor CO based on the variation of thorax impedance. Since the variation is very small compared to the base impedance, the acquisition solutions generally require complicated analog processing circuits. | Journal of Science & Technology 131 (2018) 094-099 A New Method of Measuring Impedance Cardiography for Cardiac Output Estimation by Directly Digitizing the High Frequency Modulated Signal at Lower Sampling Rate Dao Viet Hung, Phan Dang Hung, Dinh Thi Nhung*, Vu Duy Hai, Chu Quang Dan Hanoi University of Science and Technology, No. 1, Dai Co Viet, Hai Ba Trung, Hanoi, Viet Nam Received: October 11, 2018; Accepted: November 26, 2018 Abstract Cardiac output (CO) is an important hemodynamic index to assess the heart condition of the patients. Impedance cardiography (ICG) is an advanced method that can noninvasively and continuously monitor CO based on the variation of thorax impedance. Since the variation is very small compared to the base impedance, the acquisition solutions generally require complicated analog processing circuits. This makes the output influenced by external noise, temperature, and component tolerances. This study presents a new method of measuring the changes in bioimpedance with high reliability by directly digitizing the modulated thoracic impedance signal. The proposed method has a notable advantage that allows to be implemented with low-performance hardware. The experimental results showed that the extracted data is not only similar to the reference one, but also stable over long working time. The early digitization solution makes the processing steps could be highly flexible and easy to be upgraded in further research. Keywords: Cardiac Output, CO, Impedance Cardiography, ICG, Hemodynamics 1. Introduction* is to extract the thoracic impedance signal from the sensed voltage for further processing. Cardiac output (CO) is the blood volume that the heart pumps into the aorta each minute. The assessment of CO is an important criterion in the diagnosis and treatment of diseases related to heart functioning. Numerous techniques have been investigated over the past decades to evaluate cardiac output, which can be classified into two .