CPAP is an acronym for:
C - continuous
P - positive
A - airway
P - pressure
Basically, I wear a mask attached to tube, attached to a machine that sits on my bedside table and blows a continuous air pressure via a nasal or face mask or some combination through my nose (some people have ones that go over their nose and mouth) to keep the airway open while I sleep. The purpose of this sexy (not) machine is to prevent sleep apnea which is a fancy disorder for when I stop breathing periodically during sleep (see sleep study below for how they discovered this). By having a continuous flow of air, my air passages are kept open and I have a restful sleep and the added perk is that it also reduces snoring which my husband really appreciates.
Here's what it looks like:
It probably about the size of a shoe box and doesn't take up much room on the bedside table. The noise it produces is a quiet hum which doesn't disturb me or my husband during the night. In fact, it's pretty good and muffing out other house noises.
The air pressure is individually set and was determined by a specialist who monitored my sleeping during a subsequent sleep study. The CPAP keeps the air passages open by delivering filtered room air through the passageway and preventing any possible obstruction. Continued use of a CPAP is expected to decrease or eliminate snoring, encourage a restful sleep, increase energy and mental alertness and if you share the bed with someone improve their sleep and demeanor.