Randomized Trial of Oxygen Weaning Strategies Following Chest Compressions During Neonatal Resuscitation

BACKGROUND: The Neonatal Resuscitation Program (NRP) recommends using 100% O(2) during chest compressions and adjusting FiO(2) based on SpO(2) after return of spontaneous circulation (ROSC). The optimal strategy for adjusting FiO(2) is not known. METHODS: Twenty-five near-term lambs asphyxiated by umbilical cord occlusion to cardiac arrest were resuscitated per NRP. Following ROSC, lambs were randomized to gradual decrease versus abrupt wean to 21% O(2) followed by FiO(2) titration to achieve NRP SpO(2) targets. Carotid blood flow and blood gases were monitored. RESULTS: Three minutes after ROSC, PaO(2) was 229±32 mmHg in gradual wean group compared to 57±13 following abrupt wean to 21% O(2) (p<0.001). PaO(2) remained high in the gradual wean group at 10 min after ROSC (110±10 vs. 67±12, p <0.01) despite similar FiO(2) (~0.3) in both groups. Cerebral O(2) delivery (C-DO(2)) was higher above physiological range following ROSC with gradual wean (p<0.05). Lower blood oxidized/reduced glutathione ratio (suggesting less oxidative stress) was observed with abrupt wean. CONCLUSION: Weaning FiO(2) abruptly to 0.21 with adjustment based on SpO(2) prevents surge in PaO(2) and C-DO(2) and minimizes oxidative stress compared to gradual weaning from 100% O(2) following ROSC. Clinical trials with neurodevelopmental outcomes comparing post-ROSC FiO(2) weaning strategies are warranted.