BiPAP = BiLevel Positive Air pressure
In contrast to CPAP, basic BiPAP provides one set of pressure during inhalation period and another set of pressure during exhalation period.
In addition to that, there are many other added features to control more complex breathing disorders.
It is generally more expensive than CPAP and the setting can be more complicated.
It is normally used with someone with heart condition such as congested heart failure, Atrial fibrillation with irregular heart rate, COPD or neuromuscular disorders.
An overnight study to determine the optimal setting is normally recommended.
Inappropriate BiPAP setting can cause increase mortality according to some studies.