Resuscitation of newborn infants with 21% or 100% oxygen: an updated systematic review and meta-analysis.

BACKGROUND The issue of whether 21% O(2) is more effective than 100% O(2) for resuscitation of newborn infants remains controversial. OBJECTIVES We have updated the systematic review and meta-analysis including all studies reporting resuscitation of newborn infants with 21 or 100% O(2). METHODS Randomized or quasi-randomized studies of depressed newborn infants resuscitated with 21 or 100% O(2) with or without masking of treatment were considered for inclusion. The outcomes of interest included neonatal mortality and hypoxic ischemic encephalopathy. RESULTS 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(2) and 1,051 infants with 100% O(2). The risk of neonatal mortality was reduced in the 21% O(2) group compared to the 100% O(2 )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(2) in the analysis of all studies (typical RR 0.88, 95% CI 0.72, 1.08). CONCLUSIONS 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(2).