title: Lung impedance measurements to monitor alveolar ventilation.
abstract: OBJECTIVE
  Electrical impedance tomography (EIT) is an attractive method of monitoring patients during mechanical ventilation because it can provide a noninvasive continuous image of pulmonary impedance, which indicates the distribution of ventilation. This article will discuss ongoing research on EIT, with a focus on methodological aspects and limitations and novel approaches in terms of pathophysiology, diagnosis and therapeutic advancements.
  
  
  RESULTS
  EIT enables the detection of regional distribution of alveolar ventilation and, thus, the quantification of local inhomogeneities in lung mechanics. By detecting recruitment and derecruitment, a positive end-expiratory pressure level at which tidal ventilation is relatively homogeneous in all lung regions can be defined. Additionally, different approaches to characterize the temporal local behaviour of lung tissue during ventilation have been proposed, which adds important information.
  
  
  CONCLUSIONS
  There is growing evidence that supports EIT usage as a bedside measure to individually optimize ventilator settings in critically ill patients in order to prevent ventilator-induced lung injury. A standardization of current approaches to analyse and interpret EIT data is required in order to facilitate the clinical implementation.
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University Medicine, Georg-August-University Goettingen, Göttingen, Lower Saxony, Germany. omoerer@gwdg.de
authors.forename: Onnen
authors.initials: O
authors.lastname: Moerer
authors.forename: Günter
authors.initials: G
authors.lastname: Hahn
authors.forename: Michael
authors.initials: M
authors.lastname: Quintel
mesh_terms: D055371:Acute Lung Injury / Q000503:physiopathology*; D001823:Body Composition; D017097:Electric Impedance; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods*; D012121:Respiration, Artificial