Abstract
Similar to other syndromes, patients are defined as having acute respiratory distress
syndrome (ARDS) when they meet prespecified diagnostic criteria. These criteria have
evolved over time, having gained and lost complexity, but the core principles have
remained remarkably similar over the past 45 years. The specific diagnostic criteria
allow clinicians and investigators to reliably identify patients with the syndrome
of ARDS. ARDS is a form of acute diffuse lung injury occurring in patients with a
predisposing risk factor. Lung injury is characterized by inflammation leading to
increased endothelial and epithelial permeability and loss of aerated lung tissue
resulting in hypoxemia and bilateral radiographic opacities on chest radiography.
Additional physiological derangements include increased venous admixture and physiological
dead space along with decreased respiratory system compliance. The corresponding pathological
findings are lung edema, inflammation, hyaline membranes, and alveolar hemorrhage
(i.e., diffuse alveolar damage). This article discusses the evolution of the definition
of ARDS to the new Berlin definition of ARDS proposed in 2012 and its novel iterative
refinement.
Keywords
acute respiratory distress syndrome (ARDS) - acute lung injury (ALI) - diffuse alveolar
damage (DAD) - noncardiac pulmonary edema