Impedance Cardiography Derived Cardiac Output in Hemodialysis Patients: A Study of Reproducibility and Comparison with Echocardiography

Abstract

Background Hemodialysis patients experience a variety of hemodynamic abnormalities that contribute to cardiovascular disease mortality which is the leading cause of death in these patients. Impedance cardiography has been utilized in order to monitor cardiac hemodynamics with lower cost and inconvenience, but it has not been appropriately validated in the hemodialysis population. Aim We repeatedly used impedance cardiography to assess short- (48 hours) and long-term (15 days) reproducibility of cardiac output measurements and we compared baseline impedance cardiography measurements with echocardiographic measurements. Patients and Methods We studied 109 stable hemodialysis patients, aged 59.70 ± 11.97 years being on hemodialysis for 67.59 ± 40.15 months, on a non-dialysis day. Cardiac output was obtained with the BioZ impedance cardiography system (Cardiodynamics, San Diego, Ca, USA). Baseline echocardiography was performed using a Hewlett-Packard Sonos 2500 (Andover, Mass., USA). Results The values of impedance cardiography derived cardiac output were 5.28 ± 0.79, 5.27 ± 0.75 and 5.25 ± 0.74 l/min at baseline (107 patients), 48 hours (107 patients) and 15 days (98 patients) respectively, showing high reproducibility. Bland and Altman analysis estimated that bias at 48 hours and at 15 days were: −0.013 (95% confidence intervals = −0.045 to 0.019) and 0.028, (95% confidence intervals = −0.044 to 0.101), respectively. In addition baseline impedance cardiography derived cardiac output was significantly correlated with the echocardiographic derived cardiac output (r = 0.9, p < 0.0001). Conclusion Impedance cardiography is a simple non invasive technique for cardiac output estimation in hemodialysis patients which has high reproducibility when performed under controlled conditions, and is closely correlated with echocardiographic measurements of cardiac output.

Utilization of impedance cardiography in noninvasive assessment of hemodynamic status in cirrhotic patients

“…Additional increase in heart rate and accompanying increment in CO in the CPS-B group may be associated with activation of the sympathic nervous system and vasoconstrictive mediators trying to counterbalance vasodilatation. However, the hemodynamic profile of patients in the CPS-C group is consistent with an established "hyperd- Impedance cardiography has been widely used in diverse clinical settings, and its applicability has been validated with confirmatory results in comparison to both invasive methods (pulmonary artery catheterization, Fick and thermodilution) (6,7,12,13) and noninvasive (echocardiography) measures (4,14,15). ICG is based on the application of a high-frequency, low-alternating electrical current to the thorax to define changes in the current, which are associated with the cardiac events and blood flow in the thorax (16).…”

“…However, our study was not planned as a validation study; rather, we aimed to demonstrate the applicability of ICG-derived hemodynamic measurements in cirrhotic patients. The TFM and other commercially available devices equipped with ICG to define hemodynamic status were already utilized in previous researches where ICG results were confirmed and validated in comparison with invasive and noninvasive methods (4,6,7,(12)(13)(14)(15)17). Therefore, we did not need to involve any invasive or noninvasive comparative hemodynamic assessment tool.…”

Reproducibility of systemic hemodynamics in stable chronic hemodialysis: a pilot study

“…We had previously tested the reliability of this device in dialysis patients, showing that paired readings were reliably similar [3]. Recently, Karakitsos et al [12] evaluated the reproducibility of cardiac output in 109 stable HD patients using impedance cardiography. Their study, however, focused on validity and reliability of the device rather than hemodynamic variables.…”

Guest Editor: Rajiv Agarwal: Can “Diagnostic Markers” Predict Blood Pressure Response in Hypertensive Dialysis Patients?

“…(46), better BP control in the hemodynamic group was associated with more intensive diuretic therapy, but this was not the case in the other study (45), therefore, it is not clear that better volume control was the only issue involved. Impedance cardiography use is in its early stages of testing and validation in dialysis patients (47,48), and it cannot yet be recommended for decision‐making until further normative data are available.…”

“…stages of testing and validation in dialysis patients (47,48), and it cannot yet be recommended for decisionmaking until further normative data are available.…”