What type of apnea is characterized by obstruction of the airway?

Obstructive sleep apnea is defined by the presence of airway obstruction that occurs during sleep, leading to repeated episodes of apnea or hypopnea. In this condition, the muscles in the throat relax excessively, causing a blockage in the upper airway. This results in a reduction of airflow despite ongoing effort to breathe, which can lead to various symptoms such as loud snoring, gasping, or choking during sleep.

Central sleep apnea, on the other hand, is not characterized by airway obstruction but rather by a failure of the brain to transmit signals to the muscles that control breathing. Complex sleep apnea involves a combination of both central and obstructive features, making it distinct from purely obstructive forms. Mixed sleep apnea refers specifically to episodes that start as central apneas but evolve into obstructive events.

Given this understanding, obstructive sleep apnea is clearly defined by the mechanical blockage of airflow, which distinguishes it from other types of apnea.