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Basic Concepts
Published in P. Arpaia, U. Cesaro, N. Moccaldi, I. Sannino, Non-Invasive Monitoring of Transdermal Drug Delivery, 2022
P. Arpaia, U. Cesaro, N. Moccaldi, I. Sannino
Another application which exploits the characteristic impedance of the tissue and blood in the thorax, which changes with respiration and the cardiac cycle largely because of the changes in thoracic vascular volume, is Thoracic Electrical Bioimpedance (TEB), also known as Impedance Cardiography (ICG). The ICG is essentially similar to the IPG procedure: one pair of electrodes, usually placed at the base of the neck, injects an alternating electric current (frequency range of 20 Hz to 100 kHz). Correspondingly, another two electrodes, placed on xiphoid or xiphisternal joint, measure the related voltage. TEB depends on biological composition, breathings, and by the blood circulation and blood volume of thoracic vessels. After processing to remove the respiratory component, the change in impedance from the baseline impedance, Z0, is related to the cardiac cycle. Therefore, the analysis of Z0 allows to evaluate the heart health status along with calculations of certain hemodynamic parameters including stroke volume, cardiac output, cardiac index, systemic vascular resistance, and left work index [58, 74].
IPC recovery length of 45 minutes improves muscle oxygen saturation during active sprint recovery
Published in European Journal of Sport Science, 2022
Afton D. Seeley, Kevin A. Jacobs
Upon arrival at the laboratory for sessions 2–5, participants were connected to a noninvasive impedance cardiography device (Physioflow, Manitec Biomedical, Macharen, France) to continuously monitor cardiac output (Q), stroke volume (SV), and heart rate (HR). The Physioflow device emits a low-amperage (3.6 mA), high frequency (75 KHz), alternating electrical signal between two sets of electrodes. One set was placed on the supraclavicular fossa on the left side of the neck; the other set on the middle of the back at the level of the xiphoid process. Stroke volume was calculated from the measurement of changes in transthoracic electrical impedance during the cardiac cycle while simultaneous measures of ECG activity (V1 and V6) allowed for HR measurement, and therefore, calculation of Q.
Signal processing techniques applied to impedance cardiography ICG signals – a review
Published in Journal of Medical Engineering & Technology, 2022
Souhir Chabchoub, Sofienne Mansouri, Ridha Ben Salah
Impedance cardiography is a simple, non-invasive, cost-effective, and continuous technique for monitoring electrical impedance change Z(t) across the thorax, caused by blood volume change in aorta during the cardiac cycle [1]. This technique has a fast response time and it could be used as an ambulatory monitoring technique [2]. It has been successfully used in several clinical applications such as hypertension [3–15], pregnancy [16–22], surgery [23–29], and during haemodialysis [30,31]. Specifically, the ICG technique has been used to detect some cardiovascular diseases such as heart failure [32–35], myocardial infarction [36] and valvular heart diseases [37,38], as well as for systemic and pulmonary blood flow assessment based on the morphological changes in the ICG traces [39]. Moreover, it has been even used for evaluating the optimal settings of the pacemakers [40,41]. Furthermore, the possibility of using the ICG technology in the practice of emergency medicine has been discussed [42].
A method for suppressing respiratory noise in impedance cardiography and comprehensive assessment of noise reduction performance
Published in Journal of Medical Engineering & Technology, 2022
Phan Dang Hung, Chu Quang Dan, Vu Duy Hai
According to WHO, the number one cause of deaths globally is cardiovascular diseases (CVDs) [1]. It is estimated that CVDs cause about 17.9 million deaths in 2016, representing 31% of all global deaths [1]. Early detection of cardiovascular abnormalities helps doctors to determine timely appropriate therapies, thereby improving the effectiveness in the treatment of CVDs [2]. To evaluate the cardiovascular performance, especially in the intensive care unit (ICU), an important hemodynamic parameter was proposed as cardiac output (CO), which can be expressed as the product of stroke volume (SV) and heart rate (HR). Although invasive methods such as the Fick technique, dye dilution and thermodilution have great advantages of giving accurate results, their high-cost expense, high risk of implementation for each measurement, and especially the inability to monitor CO continuously are critical limitations of this group of methods [3,4]. The continuous CO measurements are particularly pertinent in diagnosing, fluid therapy and the administration of inotropes and vasopressors [5]. A well-studied method, impedance cardiography (ICG) is promising due to its ability to offer non-invasive, easy implementation, and cost-effective measurement of CO and other hemodynamics, especially the capacity for the continuous beat-to-beat monitor of SV and CO parameters [4,6–8].