Basics of Electrical Impedance Tomography and Its Application

Electrical impedance tomography (EIT) noninvasively creates images of the local ventilation and arguably lung perfusion distribution at bedside. The purpose of this article is to review and discuss methodological and clinical aspects of EIT. Whereas former investigations addressed the issue of validating EIT to measure regional ventilation, current investigations focus mainly on clinical applications such quantification of lung collapse and tidal recruitment to titrate PEEP, lung overdistension, and detection of pneumothorax. More recently studies validate EIT to measure regional lung perfusion. Indicator-free EIT measurements might be sufficient for the continuous measurement of cardiac stroke volume, but the assessment of regional lung perfusion presumably requires the use of a contrast agent such as saline.