Use of Oxygen for Resuscitation of the Extremely Low Birth Weight Infant

Abstract

The practice of mouth-to-mouth resuscitation was the first natural experiment using hypoxic gas mixtures for resuscitation. Although supplemental oxygen is now the standard during neonatal resuscitation, this practice has never been validated in prospective controlled trials. Neonatal resuscitation is primarily directed toward establishing early lung aeration and maintaining lung volume during expiration to overcome the initial vagal and hypoxic bradycardia. It remains unclear whether supplemental oxygen facilitates this process or contributes to potential hypoxia/reoxygenation injury, inhibition of breathing, and possible aggravation of atelectasis by the attenuation of nitrogen splinting. Accumulating evidence over the last decade has challenged clinicians to reconsider the optimal oxygen concentration for resuscitation of the newborn term infant. A critical review of 6 randomized trials that compared the use of room air (RA) and 100% oxygen reported that RA was associated with a significant lowering of mortality rate from 13% to 8% ( P = .0021), with a typical odds ratio (OR) of 0.57 (95% confidence interval [CI]: 0.42–0.78); however, no difference was observed for infants with a 1-minute Apgar score of <4 (typical OR: 0.81 [95% CI: 0.54–1.21]).1 In most of these trials, up to 30% of the infants in the RA group met prespecified failure criteria and received additional oxygen. However, a similar proportion of the oxygen-resuscitated infants also met the failure criteria. In term infants, the neonatal mortality rate was 5.9% in the RA group and 9.8% in the 100% O2 group (typical OR: 0.59 [95% CI: 0.40–0.870]). These results are similar to those reported in the Cochrane review by Tan et al.2 Subgroup analysis confined to preterm infants (all > 1000gm) revealed a greater reduction in mortality rate in the RA group, from 35% in the 100% O2 group to 21% in the RA group (typical OR: 0.51 [95% CI: … Address correspondence to Neil Finer, MD, UCSD Medical Center, 402 W Dickinson St, MPF Building, Suite 1-140, San Diego, CA 92103-8774. E-mail: nfiner{at}ucsd.edu