What kind of apnea is associated with the absence of airflow despite respiratory effort?

The type of apnea characterized by the absence of airflow despite ongoing respiratory effort is central apnea. In this condition, there is a lack of respiratory effort due to a failure in the central nervous system to transmit signals from the brain to the muscles that control breathing. Therefore, even though the body attempts to breathe or is capable of breathing, there is no airflow occurring because the signal to initiate breathing is absent.

Central apnea is distinct from other forms of apnea, such as obstructive apnea, where airflow is blocked despite the effort to breathe. In obstructive apnea, the body is attempting to breathe, but physical obstruction (e.g., due to collapsing soft tissues in the throat) prevents airflow. Mixed apnea involves elements of both obstructive and central apnea, where there can be periods of both obstructive events and central cessation of respiratory effort. Complex apnea is often considered as a combination of obstructive and central events as well but is typically described in the context of patients with pre-existing conditions.

By understanding the mechanisms behind central apnea, it becomes clear why this option accurately describes the absence of airflow in the presence of ongoing respiratory efforts.