Subhedar 1997.

Methods	Randomised controlled trial ‐ factorial design
Participants	42 preterm infants, entry at 96 hours if gestation < 32 weeks, mechanical ventilation from birth, surfactant treatment, and high risk of developing BPD based on score (Ryan 1996) Exclusion criteria: major congenital anomaly, structural cardiac defect, significant ductus shunting, culture‐positive sepsis, IVH with parenchymal involvement, pulmonary or GI haemorrhage, abnormal coagulation, thrombocytopenia (platelets < 50,000)
Interventions	Intravenous dexamethasone at 12‐hourly intervals for 6 days; 0.5 mg/kg/dose for 6 doses and 0.25 mg/kg/dose for a further 6 doses. Inhaled NO 5 to 20 ppm for 72 hours Control groups were not given placebo
Outcomes	Mortality, BPD at 28 days and > 36 weeks with abnormal chest radiograph Duration of ventilation, time to extubation, duration of hospitalisation, maximum grade of IVH, pulmonary haemorrhage, pneumothorax, severe PDA, NEC, ROP (stage 3 or 4) Complications including ileal perforation, upper GI haemorrhage, hyperglycaemia, hypertension, septicaemia
Notes	Note factorial design, which means that half of treated infants and half of control infants also received 72 hours of inhaled NO
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random allocation by computer‐generated random numbers and sealed envelopes. Factorial design provided 4 groups: early dexamethasone, inhaled NO, both drugs together, and neither drug.
Allocation concealment (selection bias)	Low risk	Allocation concealment: yes
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of intervention: no
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding of outcome measurements: no
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete follow‐up: yes
Selective reporting (reporting bias)	Unclear risk	All prespecified outcomes reported