What is the difference between CPAP, APAP, and Bilevel?

CPAP (continuous positive airway pressure) delivers constant airflow to people while they sleep. CPAP is often referred to as “the gold standard” treatment option and is the most commonly prescribed. APAP (automatic positive airway pressure) automatically varies its air pressure throughout the night in response to a person’s needs, making treatment more comfortable. Bilevel therapy is typically used when someone needs a higher pressure for effective treatment. See: Devices.