Acute Respiratory Distress Syndrome (ARDS) - Berlin Definition

Author: Michelle Lin, MD
Updated: 5/30/2018

Acute Respiratory Distress Syndrome (ARDS): Berlin Definition

In 2011 an initiative of the European Society of Intensive Care Medicine endorsed by the American Thoracic Society and the Society of Critical Care Medicine, developed the Berlin Definition of ARDS. It was subsequently empirically evaluated using patient-level meta-analysis of over 4,000 patients.

Clinial Feature ARDS Definition
Timing Within 1 week of inciting event or symptom onset
Imaging Bilateral opacities not fully explained by effusions, atelectasis, or nodules
Origin of edema Respiratory failure not fully explained by cardiac failure or fluid overload
Oxygenation (PaO2/FiO2)* MILD: 201-300 mmHg
MODERATE: 101-200 mmHg
SEVERE: ≤ 100 mmHg

*With PEEP (or CPAP) ≥ 5 cmH2O

Clinical Impacts

ARDS Severity Median duration of mechanical ventilation Mortality
Mild 5 days 27%
Moderate 7 days 32%
Severe 9 days 45%


  • ARDS Definition Task Force, Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E, Fan E, Camporota L, Slutsky AS. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012 Jun 20;307(23):2526-33. [PubMed].