Sleep Apnea
Continuous positive airway pressure (CPAP) machines are designed to treat a condition known as obstructive sleep apnea. According to Medline Plus, obstructive sleep apnea is the result of a blocked airway. During sleep, the muscles in the throat relax. This causes a portion of tissue (called the soft palate) to droop down. In most people, this does not cause significant airway obstruction, but some people have narrower airways, which can get blocked. When the airways are blocked, oxygen delivery to the brain decreases. This causes the brain to wake the patient in order to re-open the airway, after which they go back to sleep. This cycle can happen several times per night, making it difficult for patients to get a restful night of sleep.
CPAP Principles
CPAP machines are one of the first-line treatments for patients with obstructive sleep apnea. The purpose behind these machines, according to the American Academy of Otolaryngology, is to keep the soft palate from collapsing. These machines work by pumping air through the airways while the patient sleeps. Although the air flow is not powerful enough to interfere with inhalation or exhalation, it does force the soft palate upwards, preventing the airway from becoming obstructed. BiPAP (bi-level positive airway pressure) machines work similarly to CPAP machines but provide varying amounts of air flow, which allows them to assist with patients' breathing and manage more complex types of sleep apnea.
Mechanism
CPAP machines have three main components, according to the National Heart Lung and Blood Institute. The machine itself weighs approximately 5 lbs. and consists of a motor that is used to propel air. The motor is connected to a mask via a flexible plastic tube. The mask fits over the patient's nose (and in some cases his mouth as well) and channels the air into the patient's airway. Many CPAP machines gradually ramp up the amount of air that is propelled into the mask to make it easier for the patient to sleep.
