Final answer:
CPAP devices are predominantly used to treat patients with obstructive sleep apnea, which causes breathing interruptions during sleep due to a blocked airway.
Step-by-step explanation:
CPAP machines are commonly used in patients with sleep apnea, which is a disorder characterized by pauses in breathing during sleep. There are two types of sleep apnea: obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea is often treated with a CPAP device, which includes a mask covering the nose and sometimes the mouth, connected to a pump that forces air into the airway, keeping it open. Although this treatment is effective, alternatives such as EPAP devices or lifestyle changes are sometimes explored due to issues with compliance.