In a recent multicenter randomized controlled trial, prolonged administration of low-dose methylprednisolone (1mg/kg/day) initiated in early acute respiratory distress syndrome was associated with earlier resolution of pulmonary and extrapulmonary organ dysfunction and reduction in duration of mechanical ventilation and intensive care unit stay. However, glucocorticoids may induce serious adverse events and these adverse events might compensate the positive effect of prolonged methylprednisolone infusion and discourage physicians from treating acute respiratory distress syndrome patients with glucocorticoids. Early prediction of responsiveness to prolonged methylprednisolone infusion would be help to decide whether to continue or not prolonged methylprednisolone infusion and this could reduce the drug related adverse events. We project to evaluate the predictors of responsiveness to prolonged methylprednisolone infusion in early acute respiratory distress syndrome .

Inclusion Criteria:

• AECC definition of acute respiratory distress syndrome
• Early acute respiratory distress syndrome (within 72 h of diagnosis)
• PF ratio < 200 at PEEP ≥ 8 cmH2O

Exclusion Criteria:

• Imminent death
• Contraindication to corticosteroid treatment
• Already on more than 0.5 mg/kg of methylprednisolone or its equivalent
• Evidence of uncontrolled infection
• Refusal of managing physician to participate in the study

All patients meeting the American European Consensus definition of acute respiratory distress syndrome will be included, regardless of etiology of respiratory failure.