Sleep apnea is a common sleep disorder characterized by pauses in breathing or shallow breaths during sleep. This results in reduced oxygen levels and repeated awakening throughout the night, leaving you feeling exhausted the next day.
The most effective treatment for sleep apnea is using a system that increases air pressure in your throat so your airway doesn't collapse while you sleep. The two main types of machines used are bilevel positive airway pressure (BiPAP) and continuous positive airway pressure (CPAP). But what exactly is the difference between these two machines?
In this comprehensive guide, we'll explain what BiPAP and CPAP devices are, how they work, their pros and cons, and which one may be better for your individual needs. Understanding the key differences between these two machines is crucial so you can get the most effective treatment for a good night's rest.
BiPAP Machine
What is a BiPAP Machine?
A BiPAP machine has two pressure settings - a higher pressure when you inhale and a lower pressure when you exhale. This allows for more natural breathing. BiPAP stands for bilevel positive airway pressure.
How Does a BiPAP Machine Work?
A BiPAP machine pumps air through a face mask worn over your nose or nose and mouth while you sleep. The air is pressurized to keep your airway open by preventing collapse.
On inhalation, the device provides a higher level of pressurized air to splint your airway open. When you exhale, it drops down to a lower pressure setting so you don't feel like you're exhaling against high pressure.
Many BiPAP machines also have a back-up rate feature that functions like a ventilator to automatically deliver breaths if needed. This makes BiPAP an option for not only sleep apnea but also certain medical conditions like respiratory failure or neuromuscular disorders.
Advantages of Using a BiPAP
More Comfortable Breathing
The lower exhalation pressure allows for easier breathing out, creating a more natural breathing rhythm. This increased comfort results in better compliance for people unable to adjust to fixed CPAP pressure.
Auto Adjustability
BiPAP devices automatically sense when you inhale versus exhale and provide the appropriate high or low pressures. This means the air pressure varies based on your breathing patterns, maximizing comfort.
Better for Severe Sleep Apnea
The higher pressure on inhalation works well for people with severe sleep apnea who need more pressure to keep their airway open. The lower exhalation pressure prevents feelings of difficulty exhaling against high pressures.
May Help Certain Medical Conditions
For people with health problems affecting breathing like COPD, BiPAP can provide relief. The back-up breath feature can also aid central sleep apnea.
Disadvantages of BiPAP Therapy
Higher Upfront Cost
BiPAP machines tend to be more expensive than CPAP machines. However, the increased comfort and compliance can offset costs over time.
Takes More Getting Used To
It may take longer to get accustomed to variable pressure versus the fixed CPAP pressure. Using a ramp feature allows you to start at a lower pressure and slowly increase to the prescribed levels over time.
Dry Mouth or Nose
Like CPAP, the constant airflow can cause nasal dryness and irritation or dry mouth. This side effect is manageable using heated humidification.
Who Should Use a BiPAP Machine?
BiPAP therapy is commonly recommended for:
- People with severe obstructive sleep apnea who struggle with high CPAP pressures.
- Those with central sleep apnea. The back-up rate feature helps deliver breaths if needed.
- People with respiratory conditions like chronic obstructive pulmonary disease (COPD).
- Individuals with neuromuscular disorders like ALS or post-polio syndrome. The ventilator function assists weakened breathing muscles.
Always discuss your sleep apnea treatment options with your doctor to determine if BiPAP or CPAP is recommended for your situation. An overnight sleep study can provide data to program the appropriate pressure settings.
CPAP Device
What is a CPAP Device?
CPAP stands for continuous positive airway pressure. A CPAP machine delivers a constant flow of pressurized air through a face mask to keep your throat and airway open.
How Does CPAP Therapy Work?
During sleep, the throat and tongue muscles relax and can collapse, narrowing the airway. CPAP therapy uses just enough air pressure to splint the airway open so breathing isn't obstructed, preventing pauses in breathing.
The constant air pressure is delivered through a hose and mask or other device fitted over your nose, or nose and mouth. The pressure required is determined during an overnight sleep study.
CPAP therapy also helps keep the upper airways open using air pressure alone, without the need for uncomfortable mechanical splints or surgery. The pressurized air essentially acts as a pneumatic splint to keep the tissues in the throat from occluding.
Advantages of CPAP Therapy
Non-Invasive & Simple
CPAP machines are a non-invasive way to improve breathing during sleep. The treatment is also fairly simple to implement for most people.
Immediate Relief of Symptoms
Many patients experience immediate relief from snoring and daytime fatigue once they begin CPAP therapy. Consistent use can lead to long-term health benefits.
Improved Daytime Functioning
Restored oxygen levels during sleep and entering the deeper REM stage results in waking up feeling refreshed. This leads to improved concentration, mood, performance at work, and overall health.
Lower Cost Therapy
CPAP machines tend to have a lower upfront equipment cost than a BiPAP. If a set pressure provides adequate therapy, then a CPAP's simplicity may be preferred.
Easy Travel
A CPAP machine's small size makes it simple to pack and travel with. This helps maintain compliance even when traveling.
Disadvantages of CPAP Therapy
Air Pressure Takes Adjustment
It can take time to get used to exhaling against the constant high pressure and find the proper mask fitting. This adjustment period requires patience.
Side Effects
The pressurized air can cause nasal, throat or sinus irritation, abdominal bloating, or mask discomfort for some - particularly when getting started. Proper humidification and mask fitting helps.
Noise
The air pump and mask leakage sound generated by CPAP devices may disturb bed partners. Newer models are becoming quieter.
Who Should Use CPAP Therapy?
CPAP is the most common first-line treatment for obstructive sleep apnea. It is generally recommended for:
- Anyone with moderate to severe OSA or those with severe daytime sleepiness from apnea events.
- People who struggle with snoring that disturbs sleep.
- Individuals who experience apnea episodes during REM sleep.
- Those with risk factors like obesity or large neck circumference.
- Patients who cannot tolerate BiPAP or need basic fixed pressure support.
Comparison of BiPAP and CPAP
Now that we've covered the basics of how each machine works, let's compare the key differences between BiPAP and CPAP therapy.
Pressure Settings
The main difference between these two treatments is the air pressure delivered:
- BiPAP provides two pressures - a higher IPAP (inhalation positive airway pressure) when you breathe in, and a lower EPAP (exhalation positive airway pressure) when you breathe out.
- CPAP delivers a fixed, continuous pressure throughout the breathing cycle. No pressure adjustments are made between inhalation and exhalation.
Air Delivery
Both machines deliver pressurized air through a face mask. BiPAP varies the pressure based on your breathing phase, while CPAP maintains one steady pressure:
- BiPAP senses when you inhale versus exhale and adjusts pressure accordingly. This allows for more natural, comfortable breathing.
- CPAP provides a set pressure throughout. Your breathing adjusts to the constant pressure. Ramp features help the pressure build slowly over time.
Comfort Level
When it comes to comfort:
- BiPAP offers increased comfort for many by making exhaling against pressure easier. This leads to better compliance.
- CPAP requires getting used to exhaling against a continuous fixed pressure. Humidification and pressure ramping help with comfort.
Cost
There is usually a significant price difference:
- BiPAP machines typically have a higher upfront equipment cost given their more complex technology.
- CPAP machines are generally the more budget-friendly option. Ongoing supply costs are similar for both machines.
Best Use for Sleep Apnea Type
The type and severity of sleep apnea can dictate which machine may be preferable:
- BiPAP is often better for severe obstructive sleep apnea as the higher pressure assists breathing in, and the lower pressure prevents feelings of exhaling difficulty.
- CPAP works well for mild to moderate OSA where a fixed pressure is adequate to maintain airway patency. The simplicity can aid compliance.
- BiPAP's back-up breathing feature makes it useful for central sleep apnea where breathing pauses are caused by the brain.
Different Device Has Different Mask and Headgear
The masks and headgear used for BiPAP and CPAP machines are mostly interchangeable. However, there are some differences that may impact comfort and effectiveness:
- BiPAP masks are designed to maintain a seal at both higher and lower pressures. The seals on some CPAP masks may leak more at the higher pressures BiPAP can generate.
- CPAP masks typically have less complex headgear since they only need to maintain their seal at one continuous pressure. BiPAP headgear needs to stay put at fluctuating pressures.
- Nasal pillow masks may work well for CPAP due to the lower pressure delivery. But the higher BiPAP pressures may cause more leakage with nasal pillows. Full face or nasal masks are often better for BiPAP.
Airleak
Air leaking from the mask is common with both machines, but the consequences differ:
- With CPAP's constant pressure, mask leaks simply decrease effectiveness but don't affect device function.
- On BiPAP, major air leaks trigger the device to automatically shift to the higher IPAP pressure thinking you are inhaling. This can be disturbing and disrupt sleep until corrected.
Pressure Ramps
A ramp feature that slowly builds up pressure can help when getting used to both machines:
- On BiPAP, the ramp affects both IPAP and EPAP settings equally. The pressure difference between inhalation and exhalation is maintained as both gradually increase.
- For CPAP, the ramp brings the fixed pressure up slowly to the prescribed level. No pressure adjustment occurs during the ramp-up.
Tracking Compliance
Both CPAP and BiPAP machines can track duration of use and mask leaks to help assess compliance. However, compliance with therapy may differ:
- BiPAP's comfort from lower exhalation pressures often leads to increased patient compliance according to studies.
- CPAP has high non-compliance rates due to discomfort for some. Close follow-up helps patients acclimate to the set pressure.
Travel and Portability
Even though BiPAP machines are a little bulkier, both devices are fairly portable for travel:
- CPAP's small size and simplicity makes travel easy. But the lower pressures may not provide enough support depending on OSA severity.
- Bringing a BiPAP machine requires checking bags and AC power access. But the variable pressures provide needed support away from home.
As you can see, there are quite a few differences between these two effective sleep apnea treatments. Work closely with your doctor to determine which machine fits your sleep apnea type, comfort needs, and preferences. Proper use of either device can transform your sleep and daily life.
