Bjornson 1992.

Methods	Cross‐over RCT of prone, supine and lateral positions
Participants	Included: 4 preterm infants with a gestational age of 24 to 30 weeks and birth weight of 500 to 1500 grams requiring continuing ventilatory assistance after 7 days of life for respiratory distress syndrome Median gestational age: 26.5 weeks; median birth weight: 1003 g; age: 9 to 24 days Excluded: infants with documented infections, congenital defects, cardiac anomalies other than PDA, intraventricular haemorrhage grade III & IV and maternal history of substance abuse Setting: medical centre and general hospital, Washington, US
Interventions	Infants were placed in each of the positions for 20 minutes each over a 60‐minute session; infants underwent 6 to 9 sessions over 8 to 14 days
Outcomes	SaO2 Data collection began immediately after position change at 1‐minute intervals for 20 minutes each position; data were reported for 6 to 9 sessions
Notes	One infant completed 7/9 sessions and one completed 6 sessions due to intolerance of handling
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated but decision made by the primary investigator
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Low risk	Appears to be no loss to follow‐up