Table 4.

Classification of acute respiratory distress syndrome

	Mild	Moderate	Severe
Start time	Sudden manifestation within one week after exposure to a risk factor or appearance or worsening of respiratory symptoms
Hypoxemia - PaO2/FiO2	201 - 300 with PEEP/CPAP/EPAP ≤ 5	101 - 200 with PEEP/CPAP/EPAP ≤ 5	≤ 100 with PEEP/EPAP ≤ 5
Edema origin	Not clearly explained respiratory failure due to heart failure or volume overload
Radiological abnormalities	Bilateral opacities represented not only by nodes, effusions, masses or lobar/pulmonary collapses;

PaO₂/FiO₂ - partial pressure of oxygen/fraction of inspired oxygen; PEEP - positive end-expiratory pressure; CPAP - continuous positive airway pressure; EPAP - expiratory positive airway pressure.

Source: adapted from Associação de Medicina Intensiva Brasileira, Sociedade Brasileira de Pneumologia e Tisiologia. Diretrizes Brasileiras de Ventilação Mecânica 2013. São Paulo: AMIB; 2013. [citado 2020 Abr 19]. Disponível em https://www.amib.org.br/fileadmin/user_upload/amib/2018/junho/15/Diretrizes_Brasileiras_de_Ventilacao_Mecanica_2013_AMIB_SBPT_Arquivo_Eletronico_Oficial.pdf.⁷⁹