Berlin ARDS Criteria Calculator

About this calculator

The Berlin Definition (published in JAMA, 2012) is the current clinical standard for diagnosing and grading acute respiratory distress syndrome (ARDS). It classifies severity purely by the PaO₂/FiO₂ ratio — arterial oxygen partial pressure divided by the fraction of inspired oxygen, measured with at least 5 cmH₂O of PEEP — into mild (200–300 mmHg), moderate (100–200 mmHg), and severe (≤100 mmHg), alongside onset within one week and bilateral opacities on chest imaging not fully explained by heart failure.

Intensivists, pulmonologists, and ICU nursing staff use this ratio at the bedside to grade how impaired a ventilated patient's oxygen exchange is, which in turn guides decisions on PEEP settings, prone positioning, and the intensity of mechanical ventilation support.