Limitations of the AECC Definition of ARDS

Major Definitional Flaws

The AECC definition did not account for the heterogeneity of the syndrome across aetiological, physiological, and biological domains, which contributed to decades of failed therapeutic trials 1

The AECC definition required no specific aetiological criteria, lumping together patients with different underlying causes, such as direct pulmonary infections, indirect sepsis, aspiration, or transfusion-related injury, all under one umbrella diagnosis 1, 2
Only a minority of patients meeting AECC criteria for ARDS actually demonstrated diffuse alveolar damage on post-mortem pathological evaluation, revealing a fundamental disconnect between clinical diagnosis and underlying pathology 2

The heterogeneity inherent in the AECC definition likely contributed to the failure of multiple interventional studies targeting inflammation, coagulation, oxidative stress, and endothelial injury, as treatments effective for specific subphenotypes were diluted across heterogeneous populations 1, 2, 4
The AECC definition provided no framework for identifying which patients would benefit from specific interventions, making it impossible to apply precision medicine approaches that target treatments to those most likely to respond 1, 4