Ballard 2006.

Methods	Multi‐centre trial
Participants	582 infants < 1250 grams on assisted ventilation at 7‐21 days (or, if < 800 grams, on CPAP)
Interventions	Inhaled NO at 20 ppm initial dose for 48‐96 hours; the dose was subsequently decreased to 10, 5 and 2 ppm at weekly intervals, with a minimum treatment duration of 24 days
Outcomes	Survival without BPD at 36 weeks' postmenstrual age Secondary outcomes included duration of oxygen therapy and duration of hospitalisation. In addition, investigators prospectively evaluated the need for hospitalisation and respiratory support, including mechanical ventilation, continuous positive airway pressure and oxygen supplementation at 40, 44, 52 and 60 weeks' postmenstrual age.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised in permuted blocks at study centre
Allocation concealment (selection bias)	Low risk	Sealed envelopes
Blinding (performance bias and detection bias) All outcomes	Low risk	Masking of intervention: yes Masking of outcome assessment: yes
Incomplete outcome data (attrition bias) All outcomes	Low risk	Completeness of follow‐up: yes
Selective reporting (reporting bias)	Low risk
Other bias	Low risk
Funding Source	Low risk	Funded by a government agency (NICHD); study gas provided by industry (Ikaria)