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

• Published in: Frontiers in pediatrics Vol. 7
• Main Authors: Dekker, Janneke, Martherus, Tessa, Lopriore, Enrico, Giera, Martin, McGillick, Erin V., Hutten, Jeroen, van Leuteren, Ruud W., van Kaam, Anton H., Hooper, Stuart B., te Pas, Arjan B.
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 12-12-2019
• Subjects: breathing; oxygen; Pediatrics; preterm infant; respiratory effort; resuscitation
• ISSN: 2296-2360; 2296-2360
• DOI: 10.3389/fped.2019.00504

Background:
Infants are currently stabilized at birth with initial low FiO
2
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 O
2
concentration, followed by titration, would improve breathing effort when compared to a low O
2
concentration, followed by titration.
Methods:
In a bi-center randomized controlled trial, infants <30 weeks gestation were stabilized at birth with an initial O
2
concentration of 30 or 100%, followed by oxygen titration. Primary outcome was minute volume of spontaneous breathing. We also assessed tidal volumes, mean inspiratory flow rate (MIFR) and respiratory rate with a respiratory function monitor in the first 5 min after birth, and evaluated the duration of mask ventilation in the first 10 min after birth. Pulse oximetry was used to measure heart rate and SpO
2
values in the first 10 min. Hypoxemia was defined as SpO
2
< 25th percentile and hyperoxemia as SpO
2
>95%. 8-iso-prostaglandin F2α (8iPGF2α) was measured to assess oxidative stress in cord blood and 1 and 24 h after birth.
Results:
Fifty-two infants were randomized and recordings were obtained in 44 infants (100% O
2
-group:
n
= 20, 30% O
2
-group:
n
= 24). Minute volumes were significantly higher in the 100% O
2
-group (146.34 ± 112.68 mL/kg/min) compared to the 30% O
2
-group (74.43 ± 52.19 mL/kg/min),
p
= 0.014. Tidal volumes and MIFR were significantly higher in the 100% O
2
-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% O
2
-group [85 (64–93)%] compared to the 30% O
2
-group [58 (46–67)%],
p
< 0.001. The duration of hypoxemia was significantly shorter in the 100% O
2
-group, while the duration of hyperoxemia 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% O
2
led to higher breathing effort, improved oxygenation, and a shorter duration of mask ventilation as compared to 30% O
2
, without increasing the risk for hyperoxia or oxidative stress.
Clinical Trial Registration:
This study was registered in
www.trialregister.nl
, with registration number NTR6878.