Resuscitation in Room Air

Oxidative stress in asphyxiated term infants resuscitated with 100% oxygen. Vento M, Asensi M, Sastre J, et al. J Pediatr (March 2003);142:240-6.

Objective: To test the hypothesis that resuscitation of asphyxiated infants with pure oxygen causes hyperoxemia and oxidative stress.

Study design: Asphyxiated term newborn infants (n = 106) were randomly resuscitated with room air (RAR = 51) or 100% oxygen (OxR = 55). The Apgar score, time of the first cry, and establishment of a sustained pattern of respiration were recorded. Assays performed included: blood gases; reduced glutathione (GSH) and oxidized glutathione (GSSG) in whole blood; glutathione-related enzyme activities; and superoxide dismutase activity (SOD) in erythrocytes.

Results: The RAR group needed less time of ventilation for resuscitation (5.3 ± 1.5 vs 6.8 ± 1.2 min; P < .05). Pure oxygen caused hyperoxemia (PO₂, 126.3 ± 21.8 mm Hg) that did not occur with the use of room air (PO₂, 72.2 ± 6.8 mm Hg). GSH was decreased and GSSG, the glutathione cycle enzymes, and SOD activities were increased in both asphyxiated groups. However, the 100% oxygen-resuscitated group showed significantly greater alterations that correlated positively with hyperoxemia.

Conclusions: Asphyxia causes oxidative stress in the perinatal period, and resuscitation with 100% oxygen causes hyperoxemia and increased oxidative stress. Because there are no advantages to resuscitation with 100% oxygen, room air may be preferred under certain circumstances for the resuscitation of asphyxiated neonates.

Comment: This is a follow-up study to the original publication by this group showing possible advantages to resuscitation of asphyxiated infants in room air. The original report (published in Pediatrics 2001;107(4):642-7, and reviewed in NeoNotes ( 2-024 )) had a smaller sample size, but essentially the same findings. Asphyxiated babies resuscitated in room air cry more quickly, and have lower levels of enzymes associated with oxidative stress. It will be many years before a definitive study comparing 100% oxygen to room air resuscitation can be completed. In the meantime, I support the concept of “appropriate oxygen supplementation” after deliveries. This means that we bring our oxygen blenders and saturation monitors into the delivery rooms, and use the minimum amount of supplemental oxygen needed to achieve acceptable oxygen saturation. ABK.

Date:        10 Apr 2003
Time:        08:42:09

As we learn more about oxidative injury, particularly in the asphyxiated infant, such models of care are intriguing.

Using surrogate markers for asphyxia does not indicate outcomes, however (the authors, I am sure, know this). Elevated markers may not make any difference clinically. The next step in this array of research has to be outcome related, before changes in resuscitation protocols should be considered. (The caveat being that I don't believe there is much data that using high O2 tension improves outcomes either...).

In many NICUs we often look at the delivery room as a bus stop, rather than a destination, so do not have available those monitoring tools we leave in the NICU. As we learn more about the effects of our resuscitative efforts, and gain new tools for monitoring them, we gain a better understanding of our need to make measured repsonses. As pulse oximetry becomes more reliable with SET (Signal Extraction Technology) for example, the monitoring of SaO2 in the del room becomes not only more reliable, but essential.

The next dragon will be determining what optimal SaO2 levels should be in resuscitation of the hypoxic-ischemic infant, especially with significant peripheral hypoperfusion often illustrated by these infants. Cerebral function monitoring (aEEG) may be a new critical tool in making that determination.

In the meantime I wholly agree with Dr. Kairalla's editorial addendum! Is it the absence of supplemental FiO2 that made the difference, or is judicious use better? For now, oxygen is life (William Silverman reminds us how dangerous this axiom is...).

Ken Schroeter, DO, FAAP
Perinatal-Neonatal Medicine Fellow
Stony Brook University
email:       kenneth.schroeter@stonybrook.edu

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