Newborn on a 30% oxygen hood at 4 L/min has ABG: pH 7.29, PaCO2 52, PaO2 58. What action should be taken?

• A. Increase FiO2
• B. Initiate mechanical ventilation
• C. Initiate nasal CPAP
• D. Increase the flow

Answer: (D)

In a newborn wearing a hood, the amount of oxygen delivered to the lungs (FiO2) isn’t fixed—it rises with higher flow because more oxygen is flushed into the hood and less room air is entrained. The ABG shows both hypoxemia (PaO2 58) and hypoventilation with a respiratory acidosis (pH 7.29, PaCO2 52). The most appropriate initial step is to increase the hood flow to raise the delivered FiO2, improving oxygenation without immediately moving to invasive support. This addresses the low PaO2 directly and may also provide a small positive-pressure effect that can aid ventilation. If, after increasing flow, the CO2 remains high or the baby shows signs of respiratory distress, escalate to noninvasive positive-pressure support or ventilation.