For ARDS, there is a published study showing benefit of dexamethasone on both reduction in ventilation days and survival. The study was randomized controlled trial of 277 patients in Spain.
The mean number of ventilator-free days was higher in the dexamethasone group than in the control group (between-group difference 4·8 days [95% CI 2·57 to 7·03]; p<0·0001).
At 60 days, 29 (21%) patients in the dexamethasone group and 50 (36%) patients in the control group had died (between-group difference -15·3% [-25·9 to -4·9]; p=0·0047).
The proportion of adverse events did not differ significantly between the dexamethasone group and control group.