Low Oxygen Best for Resuscitation of Preterm Neonates

From Reuters Health Information

NEW YORK (Reuters Health) Aug 03 - Using 30% rather than 90% oxygen to resuscitate extremely low gestational age neonates results in less oxidative stress, inflammation, and chronic lung disease, new research shows.

Because the body's antioxidant system does not develop until late in gestation, preterm infants are at risk for adverse effects from hyperoxia. Prior research had established that preterm neonates could achieve target oxygen saturation values when resuscitated with 30% oxygen, but whether this approach offered any advantages over standard protocols involving higher oxygen levels was unclear.

Dr. Maximo Vento, from University Hospital La Fe, Valencia, Spain, and colleagues took up this topic by assessing the outcomes of 78 preterm neonates who were randomized to resuscitation with 30% or 90% oxygen. The target oxygen saturation values were 75% at 5 minutes and 85% at 10 minutes.

All of the subjects were extremely low gestational age neonates, defined as a gestational age at birth of no more than 28 weeks, according to the report in the September issue of Pediatrics.

Oxidative stress was evaluated by measuring the oxidized glutathione/reduced glutathione ratio in the blood and by measuring various urinary markers of stress. Inflammation was assessed by measuring plasma levels of interleukin-8 and tumor necrosis factor-alpha.

With use of 30% instead of 90% oxygen, the number of required days of supplemental oxygen fell from 22 to 6 and the number of days of mechanical ventilation dropped from 27 to 13. The rate of bronchopulmonary dysplasia at discharge was also lower in the 30% oxygen group: 15.4% vs. 31.7%.

Both the glutathione ratios and the levels of urinary markers indicated less oxidative stress in the 30% oxygen group. Similarly, the 30% oxygen group had less inflammation, as indicated by lower levels of interleukin-8 and tumor necrosis factor-alpha.

Based on the findings, the authors conclude that extremely low gestational age neonates should be resuscitated with oxygen levels not exceeding 30%.

Further studies, however, are needed with adequate statistical power to determine if use of lower oxygen levels really helps prevent bronchopulmonary dysplasia, they add.

Pediatrics 2009;124:e1-e10.