BOOSTII (UK).

Trial name or title	Benefits of oxygen saturation targeting trial 2 (UK)
Methods	Infants are randomized centrally by a secure website at the National Perinatal Epidemiology Unit (NPEU) in Oxford. A computer‐generated program that used minimization will be used to ensure balanced allocation to the two arms of the trials in each recruiting unit from a knowledge of weight, gestation and sex at birth. The NPEU is write the randomization program and hold the code. The intervention monitored through Masimo Radical SET pulse oximeters are masked by offsetting the assigned SpO2 by +/‐3% points. Staff will (a) target SpO2 88‐92% and (b) aim to maximize time spent with SpO2 between 85‐95%. From 85‐95%, the offset will be 3% above or below the actual SpO2. Outside 85‐95%, study oximeters read actual SpO2. A sample size of 1200 infants has 80% power (2p=0.05) to detect an absolute 8% increase or decrease in the composite outcome of death or major disability at 2 years. This would mean one less infant who died or was disabled for every 12 infants managed in the optimal range. This would have similar power to detect a reduction in severe ROP from 10% to 7.8% and in CLD from 40% to 32%. Data analysis will be intention to treat.
Participants	Infants <28 weeks’ gestation at birth and <12 hours old (24 hours old if the baby is outborn)
Interventions	Lower (Fn SpO2 85‐89%) vs higher (Fn SpO2 91‐95%) O2 targeting
Outcomes	Death or serious neurosensory disability at 2 years corrected age, other secondary outcomes
Starting date	2007
Contact information	Professor Peter Brocklehurst; Email: peter.brocklehurst@npeu.ox.ac.uk
Notes