However, it’s not the only variety of positive airway pressure (PAP) therapy available.
BiPAP (bilevel or biphasic positive airway pressure) is a more tailored treatment for sleep apnea that is also available for patients who qualify.
Positive Airway Pressure (PAP) Basics
In order to understand how BiPAP is different from CPAP, it’s worth reviewing the basic mechanisms of PAP therapy.
In all cases of sleep apnea (whether they are obstructive, central, or a combination of both), the body is taxed with getting enough oxygen to the bloodstream during episodes of apnea, in which pauses in breathing deplete the supply.
When enough of these pauses take place, the total amount of oxygen saturating the blood can drop to dangerous levels, creating a stress response in the body which affects many of the organs.
Untreated sleep apnea leads to chronic health problems as a result. This makes identifying and treating sleep apnea with PAP therapies critical to good health.
What is CPAP?
CPAP is used to treat OSA, which is a mechanical problem in which obstructions that occur in the upper airway as you sleep compromise your airflow.
Continuous positive airway pressure is delivered by way of a machine, tubing, and mask to prevent these obstructions by serving as a kind of upper airway “splint.” This air pressure essentially props open the throat to prevent partial or complete upper airway collapse.
These machines may offer a “ramp” feature which allows for a gradual increase in pressure at the beginning of the night so that the user can adjust more easily to it, but ultimately they will be using the therapy at a single pressure setting for most of the night.
When CPAP fails
While CPAP is mostly successful in treating most degrees of OSA, for some people, the continuity of delivered air pressure may be too uncomfortable for them: they may need to work harder to exhale against the incoming air pressure and, in doing so, find their sleep disrupted. Those with severe OSA typically have higher pressure requirements which make CPAP challenging to stick to.
Also, for people with central sleep apnea (CA), CPAP may not be as effective. Central apnea occurs when the brain forgets to signal the muscles of breathing and the diaphragm to continue assisting the lungs in breathing as you sleep. A single pressure delivery system such as CPAP may not adequately treat breathing pauses caused by misfired signals from the brain to the respiratory system.
For both of these reasons, BiPAP is frequently the next-in-line candidate for treating both OSA and CA.
What is BiPAP?
Sometimes referred to as VPAP or BPAP, the BiLevel PAP system delivers two different levels of pressurized air through the mask: one for inhalation (known as IPAP) and the other for exhalation (or, EPAP).
Generally there is a difference between these pressures, with IPAP set around 4 percent higher than EPAP. This pressure differential takes care of the problem for those with higher pressures who need a lower pressure to exhale normally and comfortably at night.
It also takes care of the challenges of people with CA because BiPAP systems are built to match or support the breathing patterns of the user so that they can breathe through potential apneas.
How BiPAP compares to CPAP
Both technologies look and sound the same. The same machine, humidification system, tubing, and mask are used to deliver the pressure, and they are cleaned and maintained in much the same way.
However, the machines themselves are adjusted to separate settings depending upon which PAP therapy they are prescribed to deliver.
[Note: PAP systems are not to be confused with ventilators, which do all of the breathing for their users; BiPAP is considered an air pressure delivery system that can also lend support to the independent breathing of its user.]
Advantages to using BiPAP:
- Fewer problems with sore throat that can be characteristic of CPAP use
- The lower exhalation pressure can make this therapy far more comfortable for users requiring higher pressures to resolve their OSA
- CPAP frequently offers a comfort setting known as “C Flex” which can reduce the exhale pressure slightly for those who need just a little bit of help; however, C Flex can vary from breath to breath, and it can only reduce exhale pressure (or EPAP) up to 3 percent, which only makes it useful for users on lower pressure settings to begin with. BiPAP is different because it delivers a steady level of pressure support during exhale that exceeds that equals or exceeds 4 percent.
- Unlike CPAP, BiPAP can assist with actual breathing by offering advanced settings that include spontaneous (S), timed (T), or both (S/T). In “S” mode, the machine detects the user’s breathing pattern at inhalation and presets its PAP delivery mode to match the user's pattern as it cycles back to the exhale. In “T” mode, the cycle between inhale and exhale is triggered by a preset rate called “breaths per minute” which does not wait for the user to breathe, but creates a pattern for them to adapt to. In “S/T” mode, the machine adapts to the user’s inhalation rate, but a backup rate that is preset to an ideal “breaths per minute” rate waits on deck in case the user fails to breathe on their own even with the “S” mode in place.
Disadvantages to using BiPAP:
- BiPAP is generally more expensive. This is the reason why insurance companies often want to see patients “fail” on CPAP before prescriptions for BiPAP can be assigned by their sleep physicians.
Who does best using BiPAP?
People with congestive heart failure and other serious diseases of the heart and lungs can benefit from using BiPAP. These include chronic obstructive pulmonary disease (COPD), respiratory failure due to fatigued muscles of breathing, pulmonary edema, pulmonary embolism, pneumonia, and atelactasis (or collapsed lobes in the lungs).
Also, people with neuromuscular problems can improve their nighttime breathing patterns by using BiPAP.
People with high pressure settings for treating OSA may find BiPAP more comfortable to use (and easier to use on a regular basis) than CPAP.
This is no small thing: sleep apnea is a serious medical illness which requires regular, consistent therapy in order for patients to find relief. If the continuous delivery system of CPAP is at the heart of a patient’s problem with PAP therapy, then a BiPAP delivery system might be just what’s needed to keep them on board with their therapy.
Is BiPAP right for you?
All PAP therapies are (and must be) prescribed by sleep physicians. It is up to your sleep doctor to determine which variety of PAP therapy is best for you. Your choices may also be limited by what your insurance payer will reimburse for, and you may need to have another attended study at the sleep clinic to identify your ideal pressure needs using BiPAP.
Certain medical conditions can disqualify you for this therapy as well, including decreased consciousness (which means the user may be incapable of removing the mask independently in an emergency), excessive respiratory secretions, low blood pressure, or risk for collapsed lung caused by pressure from extra oxygen stored in the cavities around the lung (pneumothorax).
To find out which therapy is right for you, your best bet is to consult your sleep physician, who can review your history, diagnoses, and compliance trends to ensure you are receiving the best possible treatment for your sleep apnea.
Please reach out to us at Sound Sleep Health. We have 3 locations in the greater Seattle/Kirkland areas. Call us and Improve Your Sleep Today!