Table 1.

Clinical studies comparing higher or lower initial FiO₂ for the stabilization of preterm infants in the delivery room.

Reference	Study Design	[Initial FiO2]	Objectives	Outcomes
Harling 2005 [41]	RCT GA < 31 weeks No PO; No SpO2 targets, n = 52	0.5 vs. 1.0	↓ lung inflammation	No significant differences in lung inflammation. It is possible to use lower FiO2.
Stola 2005 [42]	Cohort WB < 1500 g PO & target SpO2; n = 100	Variable vs. 1.0	Viability PaO2 at NICU admission	↓ PaO2 at NICU admission with lower FiO2 Is possible to use less FiO2.
Wang 2008 [43]	RCT GA < 32 weeks PO & target SpO2; n = 41	0.21 vs. 1.0	Viability; SpO2 targets: 80–85% at 5 min 85–90% at 7 min	Supplemental O2 necessary in 21% group.
Escrig 2008 [44] Vento 2009 [38]	RCT GA < 28 weeks PO & target SpO2 n = 78	0.3 vs. 0.9	SpO2 target 85% at 10 min Oxidative stress; Inflammation	It is possible use less FiO2. Less oxidative stress and inflammation in 30% arm.
Dawson 2009 [45]	Cohort GA < 30 weeks PO & target SpO2; n = 43	0.21 vs. 1.0	Viability SpO2 target 90% at 10 min	Supplemental O2 is necessary in 21% arm. Is possible to use less FiO2
Ezaki 2009 [46]	PO & target SpO2 n = 44	Variable vs. 1.0	Oxidative stress	↑ oxidative stress in 100% group.
Rabi 2011 [47]	RCT GA < 32 weeks PO & target SpO2; n = 106	Static 1 vs 0.21 titrate or 1.0 titrate	Viability SpO2 target 85–92%	Titrating is more effective than static No differences in timing between the 3 groups to reach the target SpO2 range
Armanian 2012 [48]	RCT GA 29–34 weeks PO & target SpO2 n = 32	0.3 vs. 1.0	SpO2 target 85%	It is possible to use less FiO2.
Rook 2014 [49]	RCT GA < 32 weeks PO & target SpO2 n = 193	0.3 vs. 0.65	Major neonatal illness Oxidative stress BPD 36 PMA SpO2 target 88–94% at 10 min	30% is as safe as 65%. No differences in oxidate stress or BPD. No differences in oxidative stress biomarkers
Kapadia 2013 [37]	RCT GA 24–34 weeks PO & target SpO2 n = 193	0.21 vs. 1.0	Oxidative stress Short-term morbidities SpO2 target 88–94%	It is possible to use less FiO2 Using 21% resulted in less oxidative stress, neonatal morbidities, and need for oxygen supplementation.
Aguar 2013 [50]	RCT GA < 30 weeks PO & target SpO2 n = 60	0.30 vs. 0.60	Death at 28 days and morbidities SpO2 target 88–94% at 10 min	It is possible to use less FiO2 No differences in oxidative stress, neonatal morbidities, or mortality.
Oei 2017 [51]	RCT GA < 32 weeks PO & target SpO2 n = 287	0.21 vs. 1.0	Major disability and death at 2 y SpO2 target 65–95% at 5 min and 85–95% until NICU admission	Increased risk of death in infants <28 weeks in the lower FiO2 group.

Abbreviations: RCT: Randomized controlled trial; PO: Pulse oximetry; GA: Gestational age; BPD: Bronchopulmonary dysplasia; PMA: Postmenstrual age; SpO₂: Oxygen saturation; FiO₂: Inspired fraction of oxygen; WB: Weight birth; NICU: Neonatal intensive care unit; PaO₂: Arterial partial pressure of oxygen. ↑ is increase and ↓ is decrease.