CPAP vs. BiPAP: What's the Difference?

If you've been diagnosed with sleep apnea, your treatment plan may include a CPAP or a BiPAP machine. Both deliver pressurized air to keep your airway open while you sleep, but they aren't the same device — and understanding the difference helps you feel more confident about your therapy.

What Both Machines Do

CPAP and BiPAP are both forms of positive airway pressure (PAP) therapy. A small bedside machine pushes a gentle, steady stream of air through a tube and mask into your airway, acting like an invisible splint that keeps the throat from collapsing. This stops the breathing pauses that define obstructive sleep apnea.

How CPAP Works

CPAP stands for Continuous Positive Airway Pressure. It delivers a single, constant level of pressure all night long — the same amount whether you're breathing in or out. For the majority of people with obstructive sleep apnea, CPAP is the first-line, gold-standard treatment, and most adjust to it well within a few weeks.

How BiPAP Works

BiPAP, or Bilevel Positive Airway Pressure, delivers two different pressures: a higher one when you breathe in (inhalation) and a lower one when you breathe out (exhalation). Because it eases the pressure on the exhale, BiPAP can feel more comfortable and natural for people who need higher pressure settings or who struggle to breathe out against constant CPAP pressure.

Who Might Need BiPAP Instead of CPAP

BiPAP is often considered when CPAP alone isn't enough or isn't tolerated. Common reasons include:

• Needing very high pressure that's uncomfortable on CPAP

• Difficulty exhaling against continuous pressure

• Certain conditions like central sleep apnea or chronic lung disease

• Low nighttime oxygen that requires more breathing support

Which Is Right for You?

The choice isn't something to guess at — it's based on your sleep study results, your pressure needs, and how you respond to therapy. Many people do beautifully on CPAP; others sleep far better once switched to BiPAP. The goal is the same: open, uninterrupted breathing and restful sleep.

If you're concerned about your sleep, the board-certified team at Metro Sleep Center can help. We offer in-lab and at-home sleep testing and personalized treatment at our Waldorf, MD and Alexandria, VA locations. Call (240) 585-5575 or book an appointment online today.

Frequently Asked Questions

What is the difference between CPAP and BiPAP?

CPAP delivers one constant air pressure all night. BiPAP delivers two — a higher pressure when you inhale and a lower one when you exhale. Both keep the airway open, but BiPAP's dual pressures can be easier for some patients, especially when higher pressures are needed.

Which is better, CPAP or BiPAP?

Neither is universally better. CPAP is the first-line, gold-standard therapy for most obstructive sleep apnea. BiPAP is usually reserved for people who cannot tolerate CPAP, need very high pressures, or have conditions like central sleep apnea or a lung disease overlap.

Who needs BiPAP instead of CPAP?

BiPAP may be recommended if you struggle to exhale against CPAP pressure, require high pressures, have central or complex sleep apnea, or have underlying lung disease. Your sleep physician decides based on your sleep study and how you respond to therapy.

Is BiPAP more expensive than CPAP?

Generally yes. BiPAP machines cost more and often require documentation that CPAP was not tolerated or effective before insurance will cover them. Your sleep team can help navigate the requirements.

Can I switch from CPAP to BiPAP?

Yes, if CPAP is not working for you, but do not stop therapy on your own. Talk to your sleep physician, who can reassess your pressures and decide whether BiPAP or another option fits. Metro Sleep Center in Waldorf, MD can help.