[Acute respiratory distress syndrome: a clinical and conceptual journey towards a global, valid, and fair definition].

Acute Respiratory Distress Syndrome (ARDS) is an acute, severe form of respiratory failure characterized by profound hypoxemia, reduced thoracopulmonary compliance, alveolar collapse leading to intrapulmonary shunt, and increased deadspace ventilation. It can originate from pulmonary or extrapulmonary causes, leading to heterogeneous pathophysiology. Clinical variability has driven the pursuit of more precise diagnostic definitions to standardize management and facilitate research. Since its first description in 1967, multiple definitions and classifications of ARDS were proposed, including the Murray Score, the American-European Consensus Conference (AECC), and the Berlin Definition. More recently, the Kigali Definition from Rwanda and the challenges posed by COVID-19 pandemic prompted further re-evaluation of the syndrome. This led to the publication of the New Global ARDS Definition in 2023, which introduced new diagnostic categories and broader diagnostic tools. The ongoing need for refinement, combined with the pathophysiological heterogeneity, motivated an exploration by expert clinician and researchers about the value of defining and subphenotyping ARDS for research, education, and clinical care. To ensure representativeness and validity, a Delphi process was conducted by a panel that included members across all world regions, representing high-intermediate and low-resource settings. This review will explore the evolution of ARDS definitions over time, and the advantages and limitations each has presented in clinical and research contexts.