Starting CPAP therapy can feel like learning a whole new language. From AHI and EPAP to humidification and ramp, there are plenty of terms that can be confusing when you're first getting started.
Understanding the basics can make it easier to use your equipment, recognize potential issues, and feel more confident about your sleep therapy.
Here are 25 common CPAP terms every new CPAP user should know.
1. AHI — Apnea-Hypopnea Index
AHI stands for Apnea-Hypopnea Index. It represents the average number of breathing interruptions you experience per hour of sleep.
In general, a lower AHI indicates fewer breathing events during the night. Your CPAP machine may display your AHI as part of your nightly therapy data.
Your healthcare provider can help you understand what your AHI means in relation to your individual treatment.
2. Apnea
Apnea is a temporary pause in breathing.
During sleep, an apnea occurs when airflow stops for at least several seconds. Obstructive sleep apnea, the most common form of sleep apnea, occurs when the airway becomes blocked or collapses during sleep.
CPAP therapy helps keep the airway open so you can continue breathing normally.
3. Auto CPAP
An Auto CPAP, sometimes called an APAP, automatically adjusts pressure within a prescribed range based on your breathing throughout the night.
Unlike a traditional CPAP machine that generally delivers one set pressure, an Auto CPAP can increase or decrease pressure as needed.
4. BiPAP
BiPAP stands for bilevel positive airway pressure.
Unlike standard CPAP therapy, which generally uses one continuous pressure, a BiPAP machine provides two pressure levels: one for inhalation and another for exhalation.
BiPAP therapy may be prescribed for certain sleep-related or respiratory conditions.
5. CPAP
CPAP stands for Continuous Positive Airway Pressure.
A CPAP machine uses a steady stream of pressurized air to help keep the airway open while you sleep. CPAP is commonly prescribed to treat obstructive sleep apnea.
6. CPAP Mask
The CPAP mask connects you to your CPAP machine and delivers the pressurized air.
There are several types of CPAP masks, including nasal masks, nasal pillow masks, and full-face masks. The right mask depends on factors such as your breathing habits, sleep position, comfort preferences, and therapy needs.
7. CPAP Tubing
CPAP tubing, also called a hose, carries pressurized air from your CPAP machine to your mask.
Tubing is available in different lengths and designs. Heated tubing is also available for compatible machines and can help manage condensation inside the hose.
8. Condensation
Condensation occurs when warm, humid air cools inside the CPAP tubing or mask.
You may hear this referred to as rainout. Condensation can result in water droplets collecting in the tubing or mask.
Adjusting your humidifier or heated tubing settings may help reduce condensation.
9. CPAP Humidifier
A CPAP humidifier adds moisture to the air delivered by your machine.
Humidification can help make therapy more comfortable by reducing symptoms such as dryness or irritation in the nose and throat.
Many CPAP machines have an integrated heated humidifier, while some travel CPAP machines offer optional humidification systems.
10. CPAP Filter
A CPAP filter helps prevent dust and other airborne particles from entering your CPAP machine.
Filters should be inspected and replaced according to the manufacturer's recommendations. A dirty or clogged filter can affect airflow and machine performance.
11. EPAP
EPAP stands for Expiratory Positive Airway Pressure.
It refers to the pressure provided while you exhale. EPAP is commonly discussed with bilevel therapy, where inhalation and exhalation pressures are different.
12. Exhalation Relief
Exhalation relief is a comfort feature available on some CPAP and Auto CPAP machines.
It temporarily lowers the pressure as you breathe out, which can make exhaling against the airflow feel more comfortable.
Different manufacturers may use different names for this feature.
13. Full-Face Mask
A full-face CPAP mask covers both your nose and mouth.
Full-face masks can be helpful for people who breathe through their mouth during sleep or who have difficulty maintaining therapy with a nasal-only mask.
14. Heated Tubing
Heated tubing contains a heating element that helps maintain the temperature of the air traveling through the hose.
It can help reduce condensation and may provide a more comfortable therapy experience, particularly when using humidification.
15. Humidification
Humidification is the process of adding moisture to the air delivered by your CPAP machine.
Without enough humidity, some users may experience a dry nose, dry mouth, or throat irritation. Too much humidity, however, can contribute to condensation.
Finding the right humidity level can take some trial and adjustment.
16. Nasal Mask
A nasal CPAP mask covers the nose and delivers pressurized air through the nose.
Nasal masks are a popular option and generally provide more coverage than nasal pillows while remaining smaller than a full-face mask.
17. Nasal Pillows
Nasal pillows are small cushions that sit directly at the entrance of your nostrils.
Nasal pillow masks typically have a minimal design and leave more of your face uncovered than traditional nasal or full-face masks.
They can be particularly appealing to people who prefer a lightweight, less-obstructive mask.
18. Obstructive Sleep Apnea
Obstructive Sleep Apnea (OSA) occurs when the upper airway becomes blocked or collapses repeatedly during sleep.
These interruptions can reduce airflow and cause repeated awakenings or changes in oxygen levels. CPAP therapy is one of the most common treatments for obstructive sleep apnea.
19. Pressure
Pressure refers to the amount of air pressure delivered by your CPAP machine.
CPAP pressure is usually measured in cmH₂O, or centimeters of water.
Your prescribed pressure or pressure range is determined by your healthcare provider based on your therapy needs.
20. Ramp
The ramp feature gradually increases CPAP pressure over a set period.
For example, a machine may begin at a lower pressure while you're falling asleep and gradually increase toward your prescribed treatment pressure.
Ramp settings vary by machine and may be adjustable depending on your prescription and device.
21. Ramp Time
Ramp time is the amount of time your machine takes to reach the prescribed treatment pressure after ramp begins.
Some machines allow you to adjust the ramp time, while others use automatic ramp features.
22. Sleep Apnea
Sleep apnea is a sleep disorder characterized by repeated interruptions in breathing during sleep.
There are different types of sleep apnea, including obstructive sleep apnea and central sleep apnea. The appropriate treatment depends on the type and severity of the condition.
23. SpO₂
SpO₂ refers to blood oxygen saturation—the percentage of oxygen carried in your blood.
Some CPAP therapy systems and compatible devices can provide information related to oxygen levels, although not every CPAP machine measures SpO₂ directly.
If you're concerned about your oxygen levels, talk with your healthcare provider.
24. Therapy Data
Therapy data is information collected by your CPAP machine about your use and, depending on the device, your therapy performance.
Data may include things such as usage hours, AHI, leak information, and pressure.
Many newer CPAP machines allow users to view some therapy information directly on the device or through a connected app.
25. Water Chamber
The water chamber, also called a humidifier chamber or water tank, is the removable reservoir used by a CPAP humidifier.
If your machine uses a humidifier, the water chamber should be filled and cleaned according to the manufacturer's instructions. Use the type of water recommended for your specific machine.
CPAP Terms Don't Have to Be Complicated
When you're new to CPAP therapy, it's normal for all the terminology to feel overwhelming. Once you understand the basics, however, reading your machine's display, choosing equipment, and talking with your healthcare provider can become much easier.
And remember: you don't have to figure everything out at once. Start by learning the terms that apply to your own machine and mask, then build from there.
If you're looking for CPAP machines, masks, tubing, filters, replacement supplies, or other sleep therapy equipment, CPAPnation offers a wide selection of CPAP products to help you find the equipment you need.
Disclaimer: The information provided on CPAPnation.com is solely for educational purposes and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. CPAPnation.com is not responsible or liable for any advice, course of treatment, diagnosis or any other information, services or products that you obtain through this site. Reliance on any information provided by CPAPnation.com is solely at your own risk.
