Table 1: Characteristics of the pragmatic definition of COVID-19 ARDS: “A patient receiving HFNO, NIV, or IMV for acute hypoxemic respiratory failure due to SARS-CoV-2 pneumonia”*.

Feature of definition

Berlin criterion

COVID application

Associated with COVID-19

No restriction by pathogen

Limited to patients with SARS-CoV-2 pneumonia


< 7 days since onset

5-14 days is common; most important factor is that the respiratory failure be from COVID-19

Bilateral opacities

Bilateral opacities consistent with pulmonary edema “may be very mild, patchy, and asymmetric”

COVID-19 pneumonia is generally a bilateral process


Positive pressure ventilation with PEEP ≥ 5 cmH2O and PaO2:FIO2 < 300 (Kigali modification SpO2:FIO2 < 315 and eliminates PEEP and positive pressure ventilation requirements)

Hypoxemic respiratory failure treated with HFNO, NIV, IMV (FIO2 ≥ 0.35 guarantees SpO2:FIO2 < 315 regardless of SpO2)

Not primarily cardiogenic/hydrostatic

Clinical assessment and judgment

Respiratory failure primarily due to COVID-19 pneumonia

*Brown SM, Peltan ID, Barkauskas C, Rogers AJ, Kan V, et al. (2021) What Does “ARDS” Mean during the COVID-19 Pandemic?. Ann Am Thorac Soc 18: 1948-1950.