Hough 2012.

Methods	DESIGN: randomised cross‐over study design Method of randomisation: sealed opaque envelopes Infant’s position: random assignment to the order of positions: supine, prone and quarter prone (right side uppermost) Blinding to intervention: no Complete follow‐up: yes Blinding to outcome measurement: no
Participants	SETTING: neonatal intensive care unit, South Brisbane, Australia DATE OF SAMPLE COLLECTION: not stated PARTICIPANTS Sample size analysed: 24 preterm infants on NCPAP were compared with 6 spontaneously breathing preterm infants (from a study of 30, only 24 were eligible for this review because of the need for respiratory support) Gestational age at birth (weeks) (mean ± SD): 28.7 ± 1.8 Postnatal age (days) (mean ± SD): 4.7 ± 3.8 Birth weight (grams) (mean ± SD): 1152 ± 263 Study weight (grams) (mean ± SD): 1085 ± 248 Associated conditions: All infants were treated for respiratory distress syndrome. Exclusions: cardiopulmonary instability, recent surgery, lung collapse, air leak syndrome, poor skin integrity
Interventions	INTERVENTIONS: quarter prone vs supine, prone vs supine, prone vs quarter prone CO‐INTERVENTIONS: none stated
Outcomes	Outcomes of interest in this review: Physiological characteristics of oxy‐haemoglobin saturation measured by a pulse oximeter (SpO2), FiO2 and SpO2/FiO2 were measured 30 minutes after each position change. Outcomes not assessed in this review: respiratory rate; distribution of ventilation was assessed by measurement of regional impedance amplitude, global inhomogeneity index and phase angle analysis, via electrical impedance tomography
User defined 1
Notes	We contacted authors of these studies to request clarification of the method of randomisation and the population shared with Hough 2013 and Montgomery 2014, which have the same registration number (Australia New Zealand Clinical Trials Registry: ACTRN12606000210572) and include participants from Hough 2012 and Hough 2013.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Method of randomisation: computer‐generated randomisation with 6 different position sequences
Allocation concealment (selection bias)	Low risk	Method of allocation: sealed opaque envelopes
Blinding of outcome assessment (detection bias) All outcomes	High risk
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete follow‐up
Selective reporting (reporting bias)	Unclear risk	No prespecified primary outcomes, so unclear
Other bias	High risk	Shares a clinical trials registry and CPAP group with Montgomery 2014, and a control group with Hough 2013 and Montgomery 2014