Sleep apnea is defined as a reduction in airflow of what magnitude for at least 10 seconds?

Sleep apnea is defined as a reduction in airflow of what magnitude for at least 10 seconds?

• A. 70% reduction for at least 12 seconds
• B. 50% reduction for at least 15 seconds
• C. 90% reduction for at least 10 seconds
• D. Complete cessation of airflow for 30 seconds

Answer: (C)

In sleep studies, events are defined by how much airflow drops and for how long. An apnea is a near-total stoppage of airflow lasting at least 10 seconds, and the standard threshold used is a 90% or greater reduction in airflow. This level of drop means the airflow is essentially almost completely blocked, distinguishing apnea from hypopneas, which are partial reductions (often around 30–50%) usually with oxygen desaturation or arousal. So, the best answer is a 90% reduction for at least 10 seconds, since it captures the nearly complete cessation that characterizes an apnea event.

In sleep studies, events are defined by how much airflow drops and for how long. An apnea is a near-total stoppage of airflow lasting at least 10 seconds, and the standard threshold used is a 90% or greater reduction in airflow. This level of drop means the airflow is essentially almost completely blocked, distinguishing apnea from hypopneas, which are partial reductions (often around 30–50%) usually with oxygen desaturation or arousal. So, the best answer is a 90% reduction for at least 10 seconds, since it captures the nearly complete cessation that characterizes an apnea event.