Phibbs 1991.

Methods	Randomized Single center Blinding of randomization: yes (sealed envelopes) Stratification based on gestational age and gender Blinding of intervention: no Complete follow‐up: yes Blinding of outcome measures: no
Participants	Premature infants Gestational age <34 weeks Birthweight 700‐1350 grams No major congenital anomaly Infants randomized: Exosurf = 38 Air Placebo = 39
Interventions	Intratracheal Exosurf Neonatal (5 ml/kg) or sham treatment (air) in delivery room after intubation and minimal ventilation
Outcomes	PRIMARY OUTCOME: Respiratory Distress Syndrome Ventiltory requirements SECONDARY OUTCOMES: Complications of prematurity Neonatal and Respiratory Mortality
Notes	Infants with congenital malformations excluded from all analyses (2 treatment, 1 control)
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Stratification based on gestational age and gender
Allocation concealment?	Low risk	Blinding of randomization: yes (sealed envelopes)
Blinding? All outcomes	High risk	Blinding of intervention: no Blinding of outcome measures: no
Incomplete outcome data addressed? All outcomes	Low risk	Complete follow‐up: yes
Free of selective reporting?	Low risk
Free of other bias?	Low risk