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

Neonatology. 2008;94(3):176-82. doi: 10.1159/000143397. Epub 2008 Jul 9.


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).

Publication types

  • Comparative Study
  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Asphyxia Neonatorum / drug therapy*
  • Controlled Clinical Trials as Topic
  • Humans
  • Infant, Newborn
  • Oxygen / administration & dosage*
  • Resuscitation / methods*


  • Oxygen