Nair 2005.

Methods	Randomised controlled trial
Participants	67 preterm infants with respiratory distress requiring CPAP in 1st 6 hours, 27 to 34 weeks' gestation (mean 32 weeks)
Interventions	HFNC: VapothermTM 5 to 6 L/min; n = 33 CPAP: bubble CPAP, Hudson prongs, 5 to 6 cmH2O; n = 34
Outcomes	Respiratory failure (leading to intubation) (pH ≤ 7.25 and PaCO2 ≥ 60 mmHg , or FiO2 > 0.70, or severe or frequent apnoea); nasal injury; BPD (as defined in Jobe 2001); mortality; length of hospitalisation; sepsis; pneumothorax
Notes	Study finished prior to achieving target sample size due to recall of Vapotherm units A full study manuscript including results was obtained from the authors Vapotherm provided equipment for the study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Stratified into 27 to 30 weeks' and 31 to 34 weeks' gestation. Permuted block randomisation
Allocation concealment (selection bias)	Low risk	Sealed envelopes
Blinding (performance bias and detection bias) Need for intubation	Unclear risk	Standardised criteria for respiratory failure, though frequency of blood gases and recording of apnoea not blinded
Blinding (performance bias and detection bias) Nasal damage	High risk	Assessment of nasal injury non‐blinded
Selective reporting (reporting bias)	Unclear risk	Not registered
Other bias	Unclear risk	Vapotherm provided equipment for the study.