The preferred treatment for moderate to severe obstructive sleep apnea is a device called a continuous positive airway pressure (CPAP) machine. The CPAP machine helps you breathe at night. A drawback to CPAP machines is that they may use one level of air pressure for the entire night. Air pressure that is set too high can cause air to leak around the mask and may also be uncomfortable. This may cause you to use the machine less.

Similar machines adjust air pressure automatically or use different air pressures when you are breathing in than when you are breathing out.

Bilevel positive airway pressure machines

Bilevel positive airway pressure machines (such as BiPAP) have two air pressure levels, one for breathing in and one for breathing out. Air pressure for breathing in is usually set higher than air pressure for breathing out. You will have to spend the night at a sleep laboratory to find the air pressure levels that work best for you.

You may find BiPAP more comfortable than CPAP because you can breathe out against a lower air pressure. As a result, you may be more likely to continue the treatment.

Auto-titrating continuous positive airway pressure (APAP)

An APAP machine can automatically decrease or increase the air pressure as needed. This may make the machine more comfortable and easier to use.

Both BiPAP and APAP machines are generally more expensive than CPAP machines.