ARDS: Are the current definitions useful?

the acute respiratory distress syndrome (ARDS) was first characterized in 1967 in a series of 12 patients with hypoxemia, tachypnea, and decreased respiratory system compliance. Following this original description, numerous definitions have been developed to identify patients with ARDS. Most recently, the Berlin definition of ARDS was published in 2012 with the aim of improving upon the feasibility, reliability, and validity of the previous American–European Consensus Conference definition. Through a novel, iterative approach, the Berlin definition was developed and refined using a patient-level meta-analysis of clinical trials and epidemiologic data. The final result of this process was a definition that utilizes readily available clinical, radiographic, and laboratory data to identify patients with ARDS. The Berlin definition stratifies patients by degree of hypoxemia, to better link physiology to patient outcomes and optimize the definition’s predictive validity for mortality. Despite these advancements, a number of limitations to the use of the Berlin definition remain. These limitations include the challenge of accurate radiographic interpretation, an inability to use these criteria in resource-limited settings, and a lack of specificity of the Berlin definition for the pathologic gold standard of ARDS, diffuse alveolar damage. Most importantly, ARDS remains underrecognized by clinicians, thereby limiting the appropriate use of evidence-based adjunctive therapies. Future work must focus on biomarkers to better identify patients with ARDS, thus facilitating improved clinical care and the development of targeted therapeutics.