Modeling of fluid shifts in the human thorax for electrical impedance tomography

Thoracic electrical impedance tomography (EIT) seems to be particularly useful for the monitoring of patients suffering from the acute respiratory distress syndrome (ARDS), because it is capable of detecting dynamic shifts of body fluids and lung aeration right at the bedside. EIT-derived numeric parameters would help the physician to evaluate the state of the lung more objectively. Therefore, we created a finite element method (FEM)-model of a human thorax and tested new ventilation indices regarding their ability to quantitatively describe structural changes in the lung due to the gravitationally dependent lung collapse. Additionally, we examined which current-injection electrode pair is best suited for the separation of lung and heart activity. Index Terms--Acute respiratory distress syndrome (ARDS), electrical impedance tomography (EIT), finite element method (FEM) thorax model, fluid shifts, ventilation indices.