Impact of the Neonatal Resuscitation Program-Recommended Low Oxygen Strategy on Outcomes of Infants Born Preterm.

OBJECTIVE: To evaluate the impact of the Neonatal Resuscitation Program (NRP)-recommended low oxygen strategy (LOX) on neonatal morbidities, mortality, and neurodevelopmental outcomes in neonates born preterm. STUDY DESIGN: In March 2011, Parkland Hospital changed from a high oxygen strategy (HOX) of resuscitation with initial 100% oxygen and targeting 85%-94% oxygen saturation for delivery room resuscitation to a LOX with initial 21% oxygen and titrating oxygen to meet NRP-recommended transitional target saturations. Neonates ≤28 weeks' gestational age born between August 2009 and April 2012 were identified. In this retrospective, observational study, neonates exposed to LOX vs HOX were compared for short-term morbidity, mortality, and long-term neurodevelopmental outcomes. Regression analysis was performed to control for confounding variables. RESULTS: Of 199 neonates, 110 were resuscitated with HOX and 89 with LOX. Compared with HOX, neonates exposed to LOX had lower oxygen exposure in the delivery room (5.2 ± 1.5 vs 7.8 ± 2.8 [∑FiO2 × time min], P < .01), spent fewer days on oxygen (30 [5, 54] vs 46 [11, 82], P = .01), and had lower odds of developing bronchopulmonary dysplasia (aOR 0.4 [0.2, 0.9]). There was no difference in mortality (17 [20%] vs 20 [18%]), but neonates exposed to LOX had greater motor composite scores on Bayley Scales of Infant and Toddler Development-Third edition assessment (91 [85, 97] vs 88 [76, 94], P < .01). CONCLUSION: The NRP-recommended LOX strategy was associated with improved respiratory morbidities and neurodevelopmental outcomes with no increase in mortality. Prospective trials to confirm the optimal oxygen strategy for the resuscitation of neonates born preterm are needed.

Perinatal asphyxia with hyperoxemia within the first hour of life is associated with moderate to severe hypoxic-ischemic encephalopathy.

OBJECTIVE: To determine whether early hyperoxemia in neonates with severe perinatal acidemia is associated with the development of hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: We identified 120 infants at ≥ 36 weeks gestational age with perinatal acidosis born at Parkland Hospital who qualified for a screening neurologic exam for cooling therapy. Based on a PaO2 measurement during the first hour of life, the cohort was divided into infants with hyperoxemia (PaO2 >100 mmHg) and those without hyperoxemia (PaO2 ≤ 100 mmHg). The rate of moderate-severe encephalopathy was compared between the groups using χ(2) analysis, as well as multiple logistic regression, taking into account baseline characteristics and confounding variables. RESULTS: Thirty-six infants (30%) had an initial PaO2 >100 mmHg. Infants with and without hyperoxemia had similar baseline maternal and infant characteristics. Infants with hyperoxemia had a higher incidence of HIE than those without hyperoxemia (58% vs 27%; P = .003). Admission hyperoxemia was associated with a higher risk of HIE (OR, 4; 95% CI, 1.4-10.5; adjusted P = .01). Among the neonates with moderate-severe HIE during the first 6 hours of life, those with hyperoxemia had a higher incidence of abnormal brain magnetic resonance imaging results, consistent with hypoxic ischemic injury, compared with those without hyperoxemia (79% vs 33%; P = .015). CONCLUSION: In neonates with perinatal acidemia, admission hyperoxemia is associated with a higher incidence of HIE. Among neonates with HIE, admission hyperoxemia is associated with abnormal brain magnetic resonance imaging findings. The judicious use of oxygen during and after resuscitation is warranted.