Treatment Options 
Continuous Positive Airway Pressure (CPAP) therapy provides one constant air pressure throughout the night.
Automatic Positive Airway Pressure (APAP) therapy automatically varies the pressure throughout the night. It automatically responds to changing dynamics of the upper airway.
Bilevel therapy is used in the circumstance where a higher pressure
is required for effective therapy and so in order to facilitate exhalation, a lower expiratory pressure is provided.