Resuscitation with room air instead of 100% oxygen prevents oxidative stress in moderately asphyxiated term neonates

Background. Traditionally, asphyxiated newborn infants have been ventilated using 100% oxygen. However, a recent multinational trial has shown that th e use of room air was just as efficient as pure oxygen in securing the surv ival of severely asphyxiated newborn infants. Oxidative stress markers in m oderately asphyxiated term newborn infants resuscitated with either 100% ox ygen or room air have been studied for the first time in this work. Methods. Eligible term neonates with perinatal asphyxia were randomly resus citated with either room air or 100% oxygen. The clinical parameters record ed were those of the Apgar score at 1, 5, and 10 minutes, the time of onset of the first cry, and the time of onset of the sustained pattern of respir ation. In addition, reduced and oxidized glutathione concentrations and ant ioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) were determined in blood from the umbilical artery during deli very and in peripheral blood at 72 hours and at 4 weeks' postnatal age. Results. Our results show that the room-air resuscitated (RAR) group needed significantly less time to first cry than the group resuscitated with 100% oxygen (1.2 +/- 0.6 minutes vs 1.7 +/- 0.5). Moreover, the RAR group neede d less time undergoing ventilation to achieve a sustained respiratory patte rn than the group resuscitated with pure oxygen (4.6 +/- 0.7 vs 7.5 +/- 1.8 minutes). The reduced-to-oxidized-glutathione ratio, which is an accurate index of oxidative stress, of the RAR group (53 +/- 9) at 28 days of postna tal life showed no differences with the control nonasphyxiated group (50 +/ - 12). However, the reduced-to-oxidized-glutathione ratio of the 100% oxyge n-resuscitated group (OxR) (15 +/- 5) was significantly lower and revealed protracted oxidative stress. Furthermore, the activities of superoxide dism utase and catalase in erythrocytes were 69% and 78% higher, respectively, i n the OxR group than in the control group at 28 days of postnatal life. Thu s, this shows that these antioxidant enzymes, although higher than in contr ols, could not cope with the ongoing generation of free radicals in the OxR group. However, there were no differences in antioxidant enzyme activities between the RAR group and the control group at this stage. Conclusions. There are no apparent clinical disadvantages in using room air for ventilation of asphyxiated neonates rather than 100% oxygen. Furthermo re, RAR infants recover more quickly as assessed by Apgar scores, time to t he first cry, and the sustained pattern of respiration. In addition, neonat es resuscitated with 100% oxygen exhibit biochemical findings reflecting pr olonged oxidative stress present even after 4 weeks of postnatal life, whic h do not appear in the RAR group. Thus, the current accepted recommendation s for using 100% oxygen in the resuscitation of asphyxiated newborn infants should be further discussed and investigated.