Resuscitation of Newborn Infants with 21% or 100% Oxygen: An Updated Systematic Review and Meta-Analysis

Abstract

<i>Background:</i> The issue of whether 21% O<sub>2</sub> is more effective than 100% O<sub>2</sub> for resuscitation of newborn infants remains controversial. <i>Objectives:</i> We have updated the systematic review and meta-analysis including all studies reporting resuscitation of newborn infants with 21 or 100% O<sub>2</sub>. <i>Methods:</i> Randomized or quasi-randomized studies of depressed newborn infants resuscitated with 21 or 100% O<sub>2</sub> with or without masking of treatment were considered for inclusion. The outcomes of interest included neonatal mortality and hypoxic ischemic encephalopathy. <i>Results:</i> Ten studies fulfilled the inclusion criteria. Of these, 6 studies were identified as being strictly randomized. In total, 1,082 infants were allocated to resuscitation with 21% O<sub>2</sub> and 1,051 infants with 100% O<sub>2</sub>. The risk of neonatal mortality was reduced in the 21% O<sub>2</sub> group compared to the 100% O<sub>2 </sub>group both in the analysis of all studies (typical RR 0.69, 95% CI 0.54, 0.88) and in the analysis of strictly randomized studies (typical RR 0.32, 95% CI 0.12, 0.84). A trend toward a decrease in the risk of hypoxic ischemic encephalopathy stage 2 and 3 was noted with resuscitation in 21% O<sub>2</sub> in the analysis of all studies (typical RR 0.88, 95% CI 0.72, 1.08). <i>Conclusions:</i> There is a significant reduction in the risk of neonatal mortality and a trend towards a reduction in the risk of severe hypoxic ischemic encephalopathy in newborns resuscitated with 21% O<sub>2</sub>.