In which type of apnea does the infant exhibit chest movement but no airflow?

In the scenario where an infant displays chest movement without airflow, the situation aligns with obstructive apnea. During obstructive apnea, there is an obstruction in the airway that prevents airflow despite the presence of respiratory muscle activity. As a result, the infant's chest may rise and fall, indicating attempts to breathe, but air does not flow into the lungs due to the blockage.

In contrast, central apnea refers to the absence of both chest movement and airflow, as it involves a failure of the brain to send signals to the muscles that control breathing. Periodic breathing involves alternating patterns of breathing and may include brief pauses, but it generally does not exhibit the chest movement without airflow characteristic of obstructive apnea. Pathologic apnea could involve either central or obstructive mechanisms but is a broader term that does not specifically describe the situation presented. Therefore, the defining characteristic of obstructive apnea is accurately represented by the presentation of chest movement without airflow.