PULMONARY FLUID ACCUMULATION AND ITS INFLUENCE ON THE IMPEDANCE CARDIOGRAM: COMPARISON BETWEEN A CLINICAL TRIAL AND FEM SIMULATIONS

Authors

  • Mark Ulbrich
  • Jens Mühlsteff
  • Matthias Daniel Zink
  • Fabienne Wolf
  • Sören Weyer
  • Thomas Vollmer
  • Stefan Winter
  • Steffen Leonhardt
  • Marian Walter

Keywords:

bioimpedance, impedance cardiography, echocardiography, heart failure, pleural effusion, lung edema, recompensation, stroke volume

Abstract

Impedance cardiography (ICG) is a simple and non-invasive method to assess hemodynamic parameters which, so far, unfortunately fails to provide accurate measurements in patients with heart failure. This study aimed to identify reasons for the inability of ICG to assess hemodynamic parameters in patients with lung edema or pleural effusion. For this, finite element simulations were conducted using a simplified simulation model based on human MRI data. This model includes volumetric changes of heart beat and aortic expansion, as well as changes during lung perfusion and erythrocyte orientation. To simulate fluid accumulations, lung tissue was stepwise substituted by body fluid. Moreover, the whole lung, as well as the left lung and right lung affected by fluid accumulation, were analyzed to establish their influence on the impedance cardiogram; the impact of changes in position was also included in the analysis. The results show a similar decrease of calculated and extracted values in all simulated measurement scenarios. In addition, the trend of these values was verified by means of a clinical trial. Using echocardiography, we confirmed that current models estimating stroke volume cannot be applied in patients with heart failure and with lung edema or pleural effusion.

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Published

2014-12-30

Issue

Section

Original Research