Following stimulation and suctioning, a full-term infant shows mild respiratory distress and cyanosis. What initial treatment should be started?

The appropriate initial treatment for an infant exhibiting mild respiratory distress and cyanosis following stimulation and suctioning is to administer oxygen. Providing supplemental oxygen can help address the immediate issue of inadequate oxygenation, as the cyanosis indicates that the infant is not receiving sufficient oxygen, which is critical for survival and preventing further complications.

In the context of the respiratory distress being mild while still requiring intervention, administering oxygen by mask is a non-invasive way to quickly improve oxygen saturation levels. This ensures that the infant's lungs receive adequate oxygenation without the need for more aggressive interventions unless the condition worsens.

While placing the infant on a radiant warmer supports thermoregulation, it does not directly address the oxygenation issue presented by respiratory distress and cyanosis. Hyperextending the newborn’s neck can potentially obstruct the airway in some cases and is not a recommended first-line action for addressing respiratory difficulties. Manual ventilation with 100% oxygen is more appropriate for moderate to severe respiratory distress, where the infant is unable to maintain adequate ventilation or oxygenation on their own. Given that the infant's distress is described as mild, starting with oxygen via mask is the safest and most effective initial intervention.