If you have severe obstructive sleep apnea, central sleep apnea, COPD, Overlap Syndrome, obesity hypoventilation, or another health condition with an obstructive or restrictive component that affects your breathing during sleep, then your doctor may recommend you use a BiPAP machine instead of a CPAP machine.
BiPAP vs. CPAP is not a question of “which therapy is better for sleep apnea?” Both machines are superior for treating apnea. They have the same purpose and function: both BiPAP and CPAP use filtered, pressurized air to keep your airway open so it doesn’t collapse during sleep.
The difference between BiPAP and CPAP is that a CPAP machine uses a continuous, steady pressure, regardless of whether you are inhaling or exhaling. (The “C” in CPAP stands for “continuous.”) BiPAP machines offer a dual pressure setting, so your inspiratory setting (IPAP) can be set at a higher pressure than your expiratory setting (EPAP). (The “Bi” in “BiPAP” stands for “bilevel,” or two levels.) This difference in pressures is sometimes called a “pressure gradient.”
Which apnea machine you use is not a question of “what works better?”—it’s a question of individual fit, based on your specific needs. CPAP is the go-to for treating obstructive sleep apnea, but there are certain health conditions that compromise breathing and lead to an imbalance in blood gas levels. You may have too little oxygen in your bloodstream or too much carbon dioxide.
For people with these types of pulmonary conditions, BiPAP can be a more effective apnea treatment because it addresses the other breathing-related issues, as well.
Also, for some individuals with a proven inability to tolerate CPAP—for example, if exhaling against the pressurized air is too labored and uncomfortable and prevents you from getting good quality sleep—BiPAP may be easier to use.
What Is a BiPAP Machine?
The term “BiPAP” is a trademarked brand name for a particular manufacturer’s (Respironics) product. (Think how we commonly say “Kleenex” when we should be asking for a “tissue.”) The official, generic term for this modality is “bilevel positive airway pressure” therapy. You may sometimes see the term “BPAP” used interchangeably with “BiPAP.” They are the same. Both BPAP and BiPAP refer to machines designed to treat sleep disordered breathing.
As mentioned earlier, BiPAP is very similar in function and design to CPAP. It differs by the addition of a second air pressure setting.
How Does a BiPAP Machine Work?
The experience of sleeping with a BiPAP is almost identical to using a CPAP. The machine on your nightstand contains a motor and air compressor (and, optionally, a humidifier to moisten the air). The BiPAP brings room air into this machine, where the air is then filtered and pressurized. The pressurized air is delivered to your airway via tubing and a mask which you wear to sleep. This air works like a splint to keep your collapsing airway open during sleep.
However, whereas CPAP has a single air pressure setting, a BiPAP allows for a differential in inspiratory and expiratory pressures. This means your doctor may prescribe one air pressure for inhaling—often, a pressure higher than a typical CPAP will allow—and a second, lower air pressure for exhaling.
This pressure gradient is helpful for people who may need additional assistance with their nighttime breathing. For example, if you have very low blood oxygen, your doctor may recommend a higher inspiratory pressure in order to get more air into your lungs. However, exhaling against that higher-than-average air pressure can be difficult. The bilevel pressure setting allows for a lower pressure when you exhale.
And if you have too much carbon dioxide in your bloodstream, the lower expiratory pressure means you don’t have to work as hard to exhale and eliminate the excess CO2. The bilevel air pressure settings enhance your body’s ability to take in and remove gases.
Benefits of BiPAP
What are some of the benefits and advantages to using BiPAP for apnea?
- BiPAP is a better treatment for those with breathing restrictions. People with breathing restrictions may have trouble getting enough oxygen and expelling enough CO2. BiPAP can improve your gas exchange, which helps the body function more efficiently. Clearing the body of CO2 can also prevent a dangerous and sometimes deadly condition called hypoxia.
- BiPAP makes exhaling easier—which is good for those with a need for a higher inspiratory pressure. If your doctor recommends a higher-than-average air pressure to help keep your airway from collapsing, then you may find exhaling against that pressure to be challenging and uncomfortable. Working to exhale is no fun, and it may actually lead to a higher blood CO2 level. Many people with a need for higher pressure end up switching from CPAP to BiPAP.
- BiPAP includes an optional breath timing feature. This setting can measure your sleep respiration rate and set an “ideal rate” for how often you should inhale and exhale over a set period of time. When you’re asleep, if you go too long without inhaling, the BiPAP will increase air pressure temporarily. This forces you to take a breath. Once you resume breathing at your normal rate, the automatic setting returns to the previous air pressure level.
Uses and Indications for BiPAP Therapy
How do you know if you need BiPAP therapy? Your doctor will tell you which to use, based on the results of your sleep study, your titration study, and your general health history.
Common reasons to use BiPAP include:
- CPAP intolerance. If you cannot tolerate CPAP, BiPAP can be approved as an alternative. However, BiPAP is traditionally more expensive than CPAP. Because of this, for your insurance to cover the change, your inability to use CPAP will need to be documented during your sleep study.
- A need for increased ventilation. If you have a pulmonary disease or other condition that requires assistance with both inhaling and exhaling, BiPAP may be a better choice for you than CPAP; for example, if you have an obstructive and restrictive component like central sleep apnea, obesity hypoventilation, COPD, or Overlap Syndrome.
Downsides of BiPAP
BiPAP has many pros, but also a few cons:
- Expense. BiPAP machines are more expensive than CPAP machines. On average, they can cost anywhere from two to four times as much. If you can get your BiPAP covered by insurance, this helps, but you may have trouble getting insurance coverage unless you can prove you need BiPAP for medical reasons.
- Adjustment period. Getting used to using a BiPAP machine may take some time. Although the mask and tubing will feel the same as using a CPAP, the need for higher pressure variations can be challenging at first for some patients.
A BiPAP machine for the treatment of sleep apnea and sleep disordered breathing is very similar to a CPAP machine. Both BiPAP and CPAP use pressurized air to keep your airway open.
The main difference between BiPAP and CPAP is that BiPAP offers bi-level air pressure. This means you can have two different air pressure settings, one for inhaling (inspiratory setting, or IPAP), and one for exhaling (expiratory pressure, or EPAP). This differential is also known as a “pressure gradient.”
The pressure gradient can be helpful for apnea patients who have additional breathing-related issues, such as COPD or obesity hypoventilation syndrome. The dual pressure feature enables these patients to improve their gas exchange by bringing in more oxygen and eliminating more CO2. BiPAP is also an effective alternative treatment for apnea patients who cannot comply with or tolerate CPAP machine therapy at higher air pressures.
David Repasky has been using CPAP treatment since 2017 and has first-hand experience with what it’s like to live with Sleep Apnea. He brings the patient’s perspective to the CPAP.com blog and has received formal training in CPAP machines, masks, and equipment.