Neonatal resuscitation adhering to oxygen saturation guidelines in asphyxiated lambs with meconium aspiration

BACKGROUND: The Neonatal Resuscitation Program (NRP) recommends upper and lower limits of preductal saturations (SpO(2)) extrapolated from studies in infants resuscitated in room air. These limits have not been validated in asphyxia and lung disease. METHODS: Seven control term lambs delivered by cesarean section were ventilated with 21% O(2). Thirty lambs with asphyxia with meconium aspiration were randomly assigned to resuscitation with 21% O(2) (n = 6), 100% O(2) (n = 6), or initiation with 21% O(2) followed by variable FIO(2) to maintain NRP target SpO(2) ranges (n = 18). Hemodynamic and ventilation parameters were recorded for 15 min. RESULTS: Control lambs maintained preductal SpO(2) near the lower limit of NRP target range. Asphyxiated lambs had low SpO(2) (38 ± 2%), low arterial pH (6.99 ± 0.01), and high PaCO(2) (96 ± 7 mm Hg) at birth. Resuscitation with 21% O(2) resulted in SpO(2) values below the target range with low pulmonary blood flow (Qp) compared to variable FIO(2) group. The increase in PaO(2) and Qp with variable FIO(2) resuscitation was similar to control lambs. CONCLUSION: Maintaining SpO(2) as recommended by NRP by actively adjusting inspired O(2) leads to effective oxygenation and higher Qp in asphyxiated lambs with lung disease. Our findings support the current NRP SpO(2) guidelines for O(2) supplementation during resuscitation of an asphyxiated neonate