CPAP, APAP, and BPAP (also called BiPAP) are forms of positive airway pressure therapy. They are prescribed after a clinical evaluation and, in many cases, a sleep study. This guide explains the basic differences so you can have a more informed conversation with your sleep clinician.
Important: Do not choose a device or change pressure settings based on an online article. Your diagnosis, sleep-study results, symptoms, other health conditions, and treatment response all matter.
What is CPAP?
CPAP stands for continuous positive airway pressure. It delivers a steady level of air pressure through a mask to help keep the airway open during sleep. For many adults with obstructive sleep apnea (OSA), CPAP is a commonly used treatment.
What is APAP?
APAP, or auto-adjusting positive airway pressure, can vary pressure during sleep within limits set by a clinician. It is not automatically right for everyone, but it may be considered when a clinician determines it is appropriate.
What is BPAP or BiPAP?
BPAP delivers one pressure while you breathe in and a lower pressure while you breathe out. It may be considered in selected circumstances, including when a person has difficulty tolerating certain pressures or has another sleep-related breathing condition. The decision requires professional evaluation.
CPAP vs. BiPAP: the practical difference
- CPAP: one continuous pressure throughout the breathing cycle.
- APAP: pressure can adjust automatically within a prescribed range.
- BPAP: separate inspiratory and expiratory pressures.
More pressure, a different device type, or a particular feature does not necessarily mean better therapy. Comfort, mask fit, leak management, and regular follow-up are all important for successful treatment.
How is the right PAP device chosen?
Your sleep clinician may consider the type and severity of sleep-disordered breathing, your sleep-study results, symptoms, medical history, and how you respond to therapy. The American Academy of Sleep Medicine guideline supports CPAP or APAP for routine treatment of adult OSA and recommends individualizing care when other conditions or treatment needs are present.
Questions to ask your clinician
- What diagnosis and sleep-study findings is this device intended to address?
- What settings are prescribed, and who should adjust them?
- Which mask style and humidification options may improve comfort?
- When should I contact the clinic about leaks, dryness, pressure intolerance, or persistent symptoms?
Key takeaway
The best device is the one selected for your clinical needs and used consistently as prescribed. If PAP therapy feels uncomfortable or ineffective, contact your sleep clinician or equipment provider for troubleshooting rather than changing settings on your own.
