Oxygen and Resuscitation: Saturations, Oxidative Stress and Outcomes in Premature Infants

Abstract

Fetus develops in a relatively hypoxemic environment in utero, however they need supplemental
oxygen at birth when born prematurely ≤32 weeks’ gestation. Reduced antioxidant defenses
from lack of induction of antioxidant enzymes at birth, predispose premature infant susceptible
to toxic effects of oxygen such as bronchopulmonary dysplasia and brain injury. Studies have
demonstrated that even short exposures to 100% oxygen at birth could have long term implications.
Guidelines and nomograms were published in 2010 regarding oxygen concentrations to
be administered along with the oxygen saturations (SpO2) to be targeted in the first ten minutes
after birth in both term and premature infants. We review the impact of differing oxygen
concentrations in the first 10 minutes soon after birth on oxygen saturations, the biochemical
effects of oxidative stress and on clinical outcomes in premature infants. Initiating resuscitation
with an oxygen concentration of 21% O2 to 30% O2 as recommended by resuscitation
guidelines is a good starting point, despite the lack of evidence of well-defined SpO2 targets in
premature neonates, which necessitate large clinical trials. Starting low oxygen concentration
at resuscitation, facilitates lower oxidative stress which is desirable in premature infants with
immature anti-oxidant defenses at birth. However, there is insufficient evidence to indicate that
resuscitation with lower oxygen concentration (≤30% O2) at birth will decrease BPD or other
clinical outcomes in premature neonates.