Bernard 1997a

Methods	n = 48, 5 centres Allocation concealment: sequentially numbered drug packs Baseline similarity: age, APACHE II Blinding: caregivers, investigating team Cointerventions: not described Withdrawals: NAC (2/16), procysteine (none), control (none). Mortality information for one withdrawn patient who received NAC was available and included in the analysis. Losses to follow‐up: none
Participants	Inclusions: Mechanical ventilation; bilateral CXR infiltrates, no LAH, P/F of 200 mmHg or less or 225 mmHg or less if PEEP > 10 cmH2O; duration of ARDS < 24 h Exclusions: Severe acute or chronic liver disease; immunocompromised
Interventions	IV NAC, 70 mg/kg every 8 hours for 10 days (total dose 2100 mg/kg), or IV procysteine, 63 mg/kg every 8 hours for 10 days, or placebo
Outcomes	30 day mortality (NAC versus control): RR 0.83 (95% CI 0.32 to 2.15) 30 day mortality (procysteine versus control): RR 0.88 (95% CI 0.36 to 2.16) Ventilator free days to day 30 (median): 11 (NAC group); 20 (procysteine group); 3 (placebo group); differences not significant at p = 0.05 level Adverse events attributed to study medication: none
Notes	Patients (n = 48) were randomized to receive NAC (n = 16), procysteine (n = 17), or placebo (n = 15).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	A ‐ Adequate