Early oxygen levels contribute to brain injury in extremely preterm infants

Funding Information: We are deeply indebted to Marita Suni, RN, for caring for the very prematurely born infants during the MEG measurements. We also express our gratitude to all our subjects and their families for preparing the way for this study. Finally, we thank the personnel of the maternity ward of the Department of Obstetrics and Gynecology and the Neonatal Intensive Care Unit at the Helsinki University Hospital and the neonatal ward at Jorvi Hospital for their cooperation. This study was supported by Päivikki and Sakari Sohlberg Foundation (to K.R.), Foundation for Pediatric Research in Finland (to K.R., M.M., S.A.), Governmental Subsidy to Clinical Research (to S.A.), Finska Läkaresällskapet (to S.A.), and Arvo and Lea Ylppö Foundation (to A.L.). The funding sources did not participate in the work. Publisher Copyright: © 2021, The Author(s). Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Background: Extremely low gestational age newborns (ELGANs) are at risk of neurodevelopmental impairments that may originate in early NICU care. We hypothesized that early oxygen saturations (SpO2), arterial pO2 levels, and supplemental oxygen (FiO2) would associate with later neuroanatomic changes. Methods: SpO2, arterial blood gases, and FiO2 from 73 ELGANs (GA 26.4 ± 1.2; BW 867 ± 179 g) during the first 3 postnatal days were correlated with later white matter injury (WM, MRI, n = 69), secondary cortical somatosensory processing in magnetoencephalography (MEG-SII, n = 39), Hempel neurological examination (n = 66), and developmental quotients of Griffiths Mental Developmental Scales (GMDS, n = 58). Results: The ELGANs with later WM abnormalities exhibited lower SpO2 and pO2 levels, and higher FiO2 need during the first 3 days than those with normal WM. They also had higher pCO2 values. The infants with abnormal MEG-SII showed opposite findings, i.e., displayed higher SpO2 and pO2 levels and lower FiO2 need,than those with better outcomes. Severe WM changes and abnormal MEG-SII were correlated with adverse neurodevelopment. Conclusions: Low oxygen levels and high FiO2 need during the NICU care associate with WM abnormalities, whereas higher oxygen levels correlate with abnormal MEG-SII. The results may indicate certain brain structures being more vulnerable to hypoxia and others to hyperoxia, thus emphasizing the role of strict saturation targets. Impact: This study indicates that both abnormally low and high oxygen levels during early NICU care are harmful for later neurodevelopmental outcomes in preterm neonates.Specific brain structures seem to be vulnerable to low and others to high oxygen levels.The findings may have clinical implications as oxygen is one of the most common therapies given in NICUs.The results emphasize the role of strict saturation targets during the early postnatal period in preterm infants.Peer reviewe