PAP Positive airway pressure

Positive airway pressure (PAP) treatment involves placing a small mask or nose tubes (also known as “nasal pillows”) over the nose or nose and mouth and blowing compressed air into the lungs. This is the most common form of treatment for obstructive sleep apnea (OSA)

Types of PAP Devices

CPAP: Continuous Positive Airway Pressure is the most commonly used PAP device. With CPAP, the level of pressure delivered to the airway is the same during both inhalation and exhalation.
Bilevel PAP: With Bilevel PAP, the pressure during inhalation is higher than during exhalation. The pressures needed to control apnea and hypopnea events with Bilevel PAP are sometimes lower than with CPAP. Because some persons have difficulty tolerating high CPAP pressures, Bilevel PAP may be used when pressures required for CPAP are relatively high.
AutoPAP: Auto-adjusting PAP devices automatically vary PAP pressures during the night to the lowest levels required to eliminate apneas and hypopneas. Some persons with OSA may find AutoPAP devices more comfortable to use, but they may be more expensive.

Additional Features
For the basic function of applying pressure to the airway, there is generally little difference among PAP devices. However, they do vary in shape, size, weight, and additional features. Commonly found features include the following:

Ramping: This feature allows the PAP device on start-up to gradually increase the pressure over a short period of time until the prescribed pressure is reached. Some users find that this allows them to fall asleep more easily and improves their ability to wear PAP.
Pressure Relief: With pressure relief, at the beginning of exhalation, a small decrease in pressure occurs. The amount of pressure reduction is adjustable. Some users find that this makes use of PAP more tolerable by making it easier to exhale.
Humidification: With PAP, large amounts of air move in and out of the nose, mouth, and upper airway. This can lead to drying of the air passages. Most PAP machines incorporate or permit the addition of humidifiers to add moisture to the air that is breathed in. This is especially important in dry, arid climates. Heated humidifiers add more moisture than humidifiers that do not heat the inhaled air.

Types of PAP Masks

There are many styles of PAP masks. The most important distinction is between those that deliver air via the nose, and those that deliver air via the nose and mouth. The latter are generally reserved for people who are mouth breathers during sleep. A comfortable, well-fitting mask with no more than minimal air leak is essential. There are no differences in efficacy among the large number of mask types. The best mask is the one you find comfortable and will wear regularly.