<qa>  What was the ARDS definition published in 2012?In 2012, an update of the ARDS definition The Berlin criteria was published and an empirical classification was proposed according to three PaO2FiO2 cut-off values at ARDS onset: severe 100 mmHg, moderate 100 - 200 mmHg, and mild 200 - 300 mmHg on positive end-expiratory pressure PEEP 5 cmH2O. However, despite that there is sufficient evidence about the interactions between PEEP and FiO2, these cut-off values did not mandate the assessment of hypoxemia under standardized guidelines. 