Principles of electrical impedance tomography and its clinical application

Objective: This review outlines the basic principle, in addition to validated and upcoming clinical use of electrical impedance tomography (EIT). EIT generates functional tomograms of the thorax for detection of changes in regional lung aeration. These images allow an intraindividual comparison of changes in regional lung function. Specifically, EIT aims to optimize ventilation therapy in patients with acute lung failure. Data Sources. PubMed: National Library of Medicine and the National Institutes of Health. Study Selection: Studies with the key words "electrical impedance tomography" since 1983. Data Extraction: Qualitative and quantitative results of the studies. Data Synthesis: We summarize basic principles of the technique and subsequent analyzing methods, and give an overview of clinical and scientific questions that can be addressed by EIT. Conclusion: Potential applications in the future as well as limitations of EIT technology are described. In summary, EIT is a promising functional tomography technology on the verge of its clinical application. (Crit Care Med 2009; 37:713-724)