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General Principles for Measuring Arterial Waves
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
Electrical cardiometry is a noninvasive method similar to impedance cardiography, in that both methods measure thoracic electrical bioimpedance. Four standard ECG electrodes are required for measurement of CO. Electrical cardiometry is a method trademarked by Osypka Cardiotronic Inc. and shows promising results in a wide range of patients (it is currently U.S. market approved for use in adults, pediatrics and neonates). Electrical cardiometry monitors have shown promise in postoperative cardiac surgical patients (both hemodynamically stable and unstable) (Funk et al., 2009). The most recent use of the electrical cardiometry monitor has been in neonates, infants and children (Song et al., 2014; Hsu et al., 2017; Altamirano-Diaz et al., 2018a, 2018b). The ICON monitor used by Altamirano-Diaz et al. (2018b) is the first and only portable battery-operated cardiac output monitor available in the world.
Intensive care
Published in Daryl Dob, Griselda Cooper, Anita Holdcroft, Philip Steer, Gwyneth Lewis, Crises in Childbirth Why Mothers Survive, 2018
An even less invasive method involves the re-launch of impedance cardiography monitoring (ICG). This technique involves placing two pairs of ECG electrodes on the neck and lower thorax. In the past ICG has suffered from unacceptably poor precision of measurement, but advances in hardware and software with the latest-generation ICG monitor (BioZ; CardioDynamics, San Diego, CA, USA), including digital signal processing (DISQ digital impedance signal quantifier; CardioDynamics, San Diego, CA, USA) and the creation of a proprietary modification to the Sramek-Bernstein equation (ZMARC impedance-modulating aortic compliance) have yielded significantly better results.22 However, further evidence is needed to confirm the levels of accuracy and precision required in clinical practice.
Increased thoracic fluid content is associated with higher risk for pneumonia in patients undergoing maintenance hemodialysis
Published in Renal Failure, 2023
Lijuan Yan, Yumei Qiu, Jin Liu, Jining Wu, Junwei Yang, Weichun He
With the development of new hardware and computational algorithms, impedance cardiography (ICG) is becoming more accurate and may provide a noninvasive alternative to hemodynamic monitoring [5,6]. Among the parameters monitored by ICG, thoracic fluid content (TFC) is an indicator for the assessment of changes in chest fluid volume [7]. Although a TFC value cannot be used to distinguish the location of excess fluid, it helps to indicate potential fluid overload, allowing further examination to localize fluid, such as pulmonary edema or pleural effusion. In most individuals, changes in the TFC values reflect altered fluid volume in the pulmonary intravascular and interstitial spaces [8]. Continuous monitoring of TFC has been used clinically to guide the regulation of fluid clearance during continuous renal replacement therapy.
Effect of Combined Grape Seed Extract and L-Citrulline Supplementation on Hemodynamic Responses to Exercise in Young Males
Published in Journal of Dietary Supplements, 2023
Brian Shariffi, Katherine Dillon, Trevor Gillum, William Boyer, Sean Sullivan, Esther Lee, Jong-Kyung Kim
SV and heart rate (HR) were measured by impedance cardiography (Physioflow, Manatec Biomedical Q-link, Paris, France). This device evaluates real-time cardiac output data, as well as other hemodynamic responses. The bioimpedance device consists of six impedance cardiography electrodes, two positioned above the clavicle in the carotid sinus of the left side of the neck, one at the fourth intercostal space of the right rib, two electrodes positioned at the xiphoid process, and one positioned at the anterior axillary line of the left arm at the fifth intercostal space. Two of the electrodes (electrodes located at the anterior axillary line and the fourth intercostal) provide a visual of a one lead ECG. Impedance cardiography measures electrical currents in thorax impedance during the cardiac cycle to calculate SV (26). This cardiography is a device that gives off high-frequency (75 kHz) and low-magnitude (1.8 mA) electrical stimuli through the use of skin electrodes during the cardiac cycle, and then relays a waveform from which SV is calculated (27). Cardiac output was calculated according to the formula: cardiac output = HR × SVi × BSA, where HR was gathered from the one lead ECG at the R-R interval. SVi is the SV index which is calculated by SV/BSA. BSA (body surface area, in m2) was calculated using the Haycock formula: BSA = 0.024265 × BM0.5378 × H0.3964, where BM is the body mass in kilograms and H is the height in centimeters. The Physioflow technique has been known to a reliable and valid method against the direct Fick method at rest and during exercise (27).
Influence of early life risk factors and lifestyle on systemic vascular resistance in later adulthood: the cardiovascular risk in young Finns study
Published in Blood Pressure, 2021
Emilia Kähönen, Heikki Aatola, Terho Lehtimäki, Atte Haarala, Kalle Sipilä, Markus Juonala, Olli T. Raitakari, Mika Kähönen, Nina Hutri-Kähönen
Participants were instructed to avoid heavy exercise and alcohol on the previous evening and smoking, caffeine-containing products, and heavy meals on the investigation day. A trained research nurse carried out the measurements in a quiet and temperature-controlled room. Participants laid in the supine position for at least 15 min before the measurement, during which period electrodes for whole-body impedance cardiography were placed on the body surface. A whole-body impedance cardiography (ICGWB) device (CircMon B202, JR Medical Ltd, Tallinn, Estonia) was used to determine the beat-to-beat cardiac index (CI; cardiac output/body surface area, l/min/m2) and systemic vascular resistance index (SVRI; systemic vascular resistance/body surface area, dyn*s/cm5*m2). Briefly, CircMon records the continuous changes in body electrical impedance during a cardiac cycle. The stroke volume and cardiac output values measured with CircMon are in agreement with the values measured by the thermodilution method and 3-dimensional echocardiography [23–25]. The repeatability of cardiac output measurements by the impedance method has been reported to be even better than that by the thermodilution method [23]. A more detailed description of the method has been previously reported [23,24].