The diagnostic value of transthoracic impedance measurement in patients who presented to the emergency department with shortness of breath and were suspected of hearth failure

Introduction: Brain Natriuretic Peptide (BNP) and Transthoracic Echocardiography (TTE) are the most commonly used as gold standard tests in patients with acute decompensated heart failure who are presented to the emergency department with shortness of breath. One of the non-invasive methods to monitor cardiovascular hemodynamic changes is the "Transthoracic impedance" measurement. The most important feature of this method is that it does not require catheterization, it does not have complication risk, it is cheap and easy to use. The presence of pulmonary edema is also supported by the thoracic fluid content (TFC) that is obtained from the transthoracic impedance measurement. Objective: The goal of this study is to determine the diagnostic value of the parameters (especially TFC) obtained from transthoracic impedance measurements in patients presented to the emergency department with shortness of breath suspected pulmonary edema due to heart failure. Materials and Methods: This prospective and cohort study was conducted between 01.11.2017-10.02.2018. Patients presented to the Akdeniz University Hospital Emergency Department with shortness of breath suspected pulmonary edema due to heart failure were included to study. Beside Transthoracic impedance measurements were performed in all study patients. Adverse cardiac events were fallowed for one weeks. Results: 113 patients were included in study. In study, 74 (65.5%) of the patients were male and 39 (34.5%) were female. The median age is 72.0 (70.0-75.0). While the BMI average is 27.7 (27.2-29.4) kg/m2.The mean values of TFC, BNP for the diagnosis of heart failure were 32.5 (31.0-37.7), 655.0 (556.1-814.4) for, respectively. There was an statistically significant different between TFC and BNP to diagnose pulmonary edema due the heart failure. BNP and TFC median values and 95% confidence intervals were 655 (557.2-818.5), 32.5 (30.9-37.7) p<0.0001. The sensitivity and specifity of TFC measurement to diagnose pulmonary edema was found as 64.3%; and 88.4% (p<0.001) respectively. Conclusion: This study has shown that measurement of TFC can be used as a good exclusion test as well as good diagnostic value in patients, presented to emergency department with shortness of breath, who are suspected to have pulmonary edema due to heart failure.