BiPAP vs CPAP Machine – Explaining The Difference

BiPAP vs CPAP Machine
Last updated: January 26, 2017

With the increased prevalence of obstructive sleep apnea, many questions have arisen as to what is the best treatment. Most patients opt for the non-invasive treatment method of PAP (or Positive Airway Pressure) but the diagnosis doesn’t end there. There is a wide range of choices, from masks to machines, so which one is best? In this article, I will discuss the differences between a BiPAP vs CPAP machine.


The CPAP machine has been the standard go-to choice for treatment of obstructive sleep apnea, but there are some specific cases in which BiPAP can be the better choice. Although, ultimately your physician should have the final word, let’s clarify some characteristics for both machines that might help you decide the BiPAP vs CPAP debate.

CPAP – Continuous Positive Airway Pressure

A CPAP machine delivers a specifically set pressure through a mask and a hose with the goal of keeping your airways open to treat obstructive sleep apnea. This is accomplished by the continuous flow of air that keeps your tongue pushed forward, and the pressure prevents your airway from relaxing too much and collapsing. When your airway gets partially or fully blocked,   an apnea or hypopnea event occurs.

During a sleep study, the sleep technician will adjust pressure settings to find the right pressure setting for your body. A CPAP machine is then prescribed and set at this specific pressure setting, preventing the collapse of your airway and limiting the occurrence of apneas.

The correct pressure is set after measurements of pressure (i.e. titrations) during your sleep. It is important to note that it is the pressure that keeps the airways open, not the actual flow of air. Once the mask is placed on the head and the machine is turned on, the pressure buildup accomplishes the desired result.

Most modern CPAP machines have a Ramp feature as well, which allows starting out with lower pressure before falling asleep. The pressure then increases overnight up to the therapeutic level.The downside of this machine is that it isn’t as comfortable when it comes to exhaling against the continuous pressure, but that is rather subjective. Patients have complained to have felt as if they had to force their breathing out when exhaling and, after problems with adapting, BiPAP comes into play.​ Read more benefits of CPAP machines here and here.

BiPAP – Bilevel Positive Airway Pressure

Although the BiPAP therapy is essentially set up in the same way as CPAP, the BiPAP machine has two levels of pressure: inspiratory (IPAP) and a lower expiratory positive airway pressure (EPAP) to provide the easier exhalation. The IPAP pressure is higher than the EPAP and, due to this occurrence, there is also extra respiratory support. The respiratory support is calculated by subtracting the EPAP from the IPAP, and the higher this ratio is, the more the lungs expand and contract providing better ventilation.

BiPAP is usually prescribed to patients with high pressure settings and not necessarily to those with uncomplicated obstructive sleep apnea. It is also used in certain cases of cardiopulmonary disorders such as congestive heart failure, neuromuscular disorders, or other lung disorders where patients need extra respiratory support.

Should I Get A CPAP Or BiPAP?

A CPAP machine is the default treatment for obstructive sleep apnea as it treats the problem in most patients. If you are having trouble sleeping comfortably, you might want to discuss a possible switch to BiPAP  with your sleep physician. Many CPAP machines these days have additional sensors that can detect when you're exhaling, so make sure you are fully utilizing your current setup before trading it in.

Recommended PAP Machines

Choosing between a BiPAP vs CPAP machine depends on what solution you're looking for. One recent improvement in the PAP machine industry is the Auto CPAP machine. Using an onboard algorithm, it will adjust your pressure settings to give you the best CPAP therapy and avoid sleep apnea occurrences. It does not come preset with just one setting, but typically provides continuous pressure once it has found the best setting for you. Below are my recommendations for a CPAP, BiPAP, and Auto CPAP machine.

Recommended CPAP Machine

​The ResMed AirSense 10 is one of the best CPAP machines created. It has a fantastic feature set, looks nice on your night stand, and is easy to maintain.

Recommended BiPAP Machine

​Philips Respironics owns the BiPAP trademark and makes one of the best BiPAP machines, the DreamStation BiPAP Pro. It is highly rated and offers great features.

Recommended Auto CPAP Machine

​Philips Respironics also created a highly recommended Auto CPAP, the DreamStation Auto CPAP DSX500T11. It has a humidifier and heated tube to increase comfort. This is also highly recommended if you want to try CPAP therapy, but you haven't done a sleep study.

BiPAP vs CPAP Machine - Conclusion


  • Single pressure set
  • Suitable for most patients with sleep apnea​


  • Two pressures set, one for inhale one for exhale
  • Better for patients with lung disorders or similar ailments

​All in all, both machines are extremely beneficial for patients with obstructive sleep apnea who need the appropriate therapy to improve long-term health. Hopefully, I have helped you decide which one is best for you.

There are additional products you can try before spending the money on a sleep study. Check out our reviews of the best chin straps for sleep apnea.

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