ApneaHypopnea

Apnea-hypopnea refers to episodes during sleep when breathing is paused (apnea) or reduced (hypopnea). These events are most often assessed with overnight sleep studies and classified as obstructive, central, or mixed.

An apnea lasts at least 10 seconds and is characterized by a complete cessation of airflow. A hypopnea is a partial reduction in airflow accompanied by blood-oxygen desaturation or an arousal from sleep.

The condition is quantified by the apnea-hypopnea index (AHI), the average number of apneas and hypopneas per hour of sleep. Severity is generally categorized as mild (5–15), moderate (15–30), or severe (>30) events per hour.

Obstructive apnea results from upper airway collapse during sleep, while central apnea arises from reduced respiratory drive from the brain; mixed apnea contains elements of both. Risk factors include obesity, male sex, older age, smoking, and nasal congestion, among others, and the condition is associated with daytime sleepiness, decreased concentration, snoring, and an increased risk of cardiovascular disease, hypertension, stroke, and metabolic problems.

Diagnosis is by polysomnography in a sleep laboratory or home sleep apnea testing. Management strategies include continuous positive airway pressure (CPAP) as first-line therapy; alternatives such as bilevel PAP or oral appliances; weight loss, positional therapy, and, in selected cases, surgery. Ongoing management often requires adherence monitoring and treatment adjustments to address comorbid conditions and improve quality of sleep.