The Effect of Initial High vs. Low FiO2 on Breathing Effort in Preterm Infants at Birth: A Randomized Controlled Trial

Background Infants are currently stabilized at birth with initial low FiO2 which increases the risk of hypoxia and suppression of breathing in the first minutes after birth. We hypothesized that initiating stabilization at birth with a high O2 concentration, followed by titration, would improve breathing effort when compared to a low O2 concentration, followed by titration. Methods In a bi-centre randomized controlled trial, infants 95%. 8-iso-prostaglandin F2α (8iPGF2α) was measured to assess oxidative stress in cord blood and 1 and 24 hours after birth. Results 52 infants were randomized and recordings were obtained in 44 infants (100% O2-group: n=20, 30% O2-group: n=24). Minute volumes were significantly higher in the 100% O2-group (146.34 ± 112.68 mL/kg/min) compared to the 30% O2-group (74.43 ± 52.19 mL/kg/min), p=0.014. Tidal volumes and MIFR were significantly higher in the 100% O2-group, while the duration of mask ventilation given was significantly shorter. Oxygenation in the first 5 min after birth was significantly higher in infants in the 100% O2-group (85 (64 – 93)%) compared to the 30% O2-group (58 (46 – 67)%), p<0.001. The duration of hypoxemia was significantly shorter in the 100% O2-group, while the duration of hyperoxia was not different between groups. There was no difference in oxidative stress marker 8iPGF2α between the groups. Conclusion Initiating stabilization of preterm infants at birth with 100% O2 led to higher breathing effort, improved oxygenation, and a shorter duration of mask ventilation as compared to 30% O2, without increasing the risk for hyperoxia or oxidative stress.