title: Lung volume assessment in acute respiratory distress syndrome.
abstract: OBJECTIVE
  Measurements of lung volumes allow evaluating the pathophysiogical severity of acute respiratory distress syndrome (ARDS) in terms of the degree of reduction in aerated lung volume, calculating strain, quantifying recruitment and/or hyperinflation, and gas volume distribution. We summarize the current techniques for lung volume assessment selected according to their possible usage in the ICU and discuss the recent findings obtained with implementation of these techniques in patients with ARDS.
  
  
  RESULTS
  Computed tomography technique remains irreplaceable in terms of quantitative aeration of different lung regions, but the commonly used cut-offs for classification may be questioned with recent findings on nonpathological lungs. Monitoring end expiratory lung volume using nitrogen washout technique enhanced our understanding on lung volume change during positioning, pleural effusion drainage, intra-abdominal hypertension, and recruitment maneuver. Recent studies supported that tidal volume could not surrogate tidal strain, which needs measurement of functional residual capacity and which is correlated with pro-inflammatory lung response.
  
  
  CONCLUSIONS
  Although lung volume measurements are still limited to research area of ARDS, recent progress in technology provides clinicians more opportunities to evaluate lung volumes noninvasively at the bedside and may facilitate individualization of ventilator settings based on the specific physiological understandings of a given patient.
authors.affiliation: Interdepartmental Division of Critical Care Medicine, University of Toronto, Keenan Research Institute, and Department of Critical Care Medicine, St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Lu
authors.initials: L
authors.lastname: Chen
authors.forename: Laurent
authors.initials: L
authors.lastname: Brochard
mesh_terms: D006801:Humans; D008168:Lung / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008176:Lung Volume Measurements / Q000379:methods*; D000067716:Point-of-Care Testing; D011175:Positive-Pressure Respiration / Q000379:methods; D001261:Pulmonary Atelectasis / Q000503:physiopathology; D012128:Respiratory Distress Syndrome / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed