Subjects randomized to this arm will receive combined standard aerosolized doses of budesonide (0.5 mg) and formoterol (20 mcg) twice daily, with at least 6 hours between doses, for 5 days for a total of 10 doses or until hospital discharge or death, with the first dose administered as soon as possible following randomization but not later than 4 hours.

Subjects randomized to this arm will receive normal saline, the quantity, appearance and timing of the doses the same as the intervention arm.

Subjects will receive the standard aerosolized dose of budesonide (0.5 mg).

Oxygen saturation (SpO2) was measured by pulse oximetry. FiO2 is the assumed proportion of oxygen concentration participating in gas exchange in the alveoli. All S/F measurements were performed per standard operating protocol using a Venturi mask titrated to obtain an oxygen saturation of 94 ± 2% unless the patient met this goal on room air or clinical status dictated an alternative delivery mode. This outcome measure was analyzed as a longitudinal continuous variable by a mixed effect model. The formula for the calculation of SpO2/FiO2 (or S/F ratio) is %saturation/proportion of FiO2 concentration.

The data in the table below represent the greatest change from baseline observed for any one participant over all individual post-baseline measurements.

ARDS was defined per Berlin definition. Chest radiographs of all ventilated (non-invasive or invasive) patients were reviewed as consistent or not consistent with ARDS by the site investigator. A second adjudication was performed by an alternate principal investigator blinded to subject identification and clinical data. Final diagnosis of ARDS was determined centrally after chest radiograph adjudication was considered together with other relevant clinical data.

Subjects randomized to this arm will receive combined standard aerosolized doses of budesonide (0.5 mg) and formoterol (20 mcg) twice daily, with at least 6 hours between doses, for 5 days for a total of 10 doses or until hospital discharge or death, with the first dose administered as soon as possible following randomization but not later than 4 hours.

Oxygen saturation (SpO2) was measured by pulse oximetry. FiO2 is the assumed proportion of oxygen concentration participating in gas exchange in the alveoli. All S/F measurements were performed per standard operating protocol using a Venturi mask titrated to obtain an oxygen saturation of 94 ± 2% unless the patient met this goal on room air or clinical status dictated an alternative delivery mode. This outcome measure was analyzed as a longitudinal continuous variable by a mixed effect model. The formula for the calculation of SpO2/FiO2 (or S/F ratio) is %saturation/proportion of FiO2 concentration.

Intention to Treat analysis. The patient population for each day is indicated in the category by (treatment arm, placebo arm).

Subjects randomized to this arm will receive combined standard aerosolized doses of budesonide (0.5 mg) and formoterol (20 mcg) twice daily, with at least 6 hours between doses, for 5 days for a total of 10 doses or until hospital discharge or death, with the first dose administered as soon as possible following randomization but not later than 4 hours.