CPAP Machine Explained

What is a CPAP Machine?

You have been diagnosed with obstructive sleep apnea (OSA) which means you stop breathing during your sleep. What happens in OSA is that the airway becomes blocked which limits or prevents the air coming in from the nose to the lungs. The airway can become blocked in more than one place along the airway, not everyone is the same.  Sometimes the blockage occurs because of excess fatty tissue or enlarged tonsils and adenoids.  Sometimes the structure of the jaw contributes to the blockage.  The blockage causes your oxygen levels to drop and increases your work of breathing.  At the end of each blockage event, you have a mini awakening, you may or may not remember this.  This is why people with OSA are very sleepy during the day.  When the airway in your upper respiratory tract is blocked ( it does not matter where the blockage is), Continuous positive airway pressure (CPAP) can work to keep the airway open.  CPAP is the considered the first line treatment for adults with OSA.

The purpose of a CPAP machine is to make sure you keep breathing while you sleep.

Try this experiment…

Find a piece of typical printing paper, roll it into a tube. Create a seal with your mouth around the tube. Now, put your hand on the other end and breath in and out.  You will see the middle of the “tube” collapse.  That is what happens to your airway when you have a blockage.  Imagine now, that you blow air into the tube with enough force to push the hand out of the way, which is how a CPAP Machine works, except it splints or pushes the blocked airway open and holds it open as long as the CPAP is used.

In order for CPAP to work, some form of a facial mask is required.  Masks come in all different shapes and sizes.  Search here to see the different ones –  Some people use a mask that covers both the nose and the mouth, some people use what are called “pillows” which fit into the front part of the nose.  There are masks that have gel cushions and some have silicone which help to form the seal. Finding the mask that works the best for you is important.

Sometimes people go to the sleep laboratory for a “titration” study. This study finds the best pressure to keep your airway open.  Some people have an autotitration machine (see below) which automatically adjusts the pressure based on changes it detects in the airway.  After a period of time, the doctor will look to see what the best pressure is that provides the best therapy. Sometimes people just use the autotitrating machines all of the time and sometimes they go on CPAP.

The titrated pressure is the pressure of air at which most (if not all)  apnea events have been prevented.  The pressure is measured in centimeters of water pressure (cmH2O).  Most machines can provide pressures from 4-20 cmH2O.  The majority of people need a pressure between 6 and 14 cmH2O.

According to the National Sleep Foundation, many people report immediate symptom relief from CPAP therapy. Patients also report increased energy, feeling less sleepy and have better mental alertness during the day. Not everyone responds the same, but over time, the benefits are many.  In addition to just feeling better, the use of CPAP has been shown to improve insulin resistance, blood pressure, brain function and a whole lot more! .  Wow, all that and very few side effects!

Not everyone takes to CPAP right away, but persistence pays off!  Figure out a plan that works for you to adjust to using CPAP.  For example, some people wear the mask while awake to get used to having it on with or without the CPAP machine on.

FUN FACT: Did you know CPAP machines have been around since 1981!  The first machines were almost as big as window air conditioning unit!  But the clinicians who worked with sleep apnea patients were excited because before CPAP, there were few options to be treated. A whole new era began.

Now, the new machines very small and much quieter.  If your CPAP machine seems outdated, contact your healthcare provider or your insurance company. Typically, the devices are covered by insurance and may be replaced every 5 years or so.

Now that you know how CPAP works, what kind of CPAP machines are there?

Fixed-pressure CPAP

Most patients are prescribed what is called “fixed CPAP”. A fixed pressure CPAP machine delivers a constant flow or pressure of air into your airway .  It is important to understand, however, that it is the air pressure, and not the movement of the air, that prevents the airway from collapsing. When the machine is turned on, but prior to the mask being placed on your face, a flow of air comes through the mask. After the mask is placed on your face, it creates a seal. It is the combination of the seal and the flow of air that creates the pressure.

Automatic positive airway pressure  

An automatic positive airway pressure device (APAP, AutoPAP, AutoCPAP) automatically finds the right pressure and fine tunes the amount of pressure delivered to the patient. The pressure may have many changes through out the night.  Why does it do this? During certain positions or changes in sleep, the pressure may need to go up or down, however, the goal is to have the  minimum amount of pressure required to keep the airway open.

Most machines do this on a breath-by-breath basis.  Each manufacturer has a special way measure and provide pressure.

Other Settings and things

There are also some other settings to help make things more custom to your needs.  These include a setting to help for breathing out, sometimes called expiratory pressure relief or C-Flex.  There is also a ramp feature.  The ramp feature lets you set the pressure lower when you go to bed.  As you fall asleep, the pressure gradually and gently ramps up over a set amount of time.


Almost all the machines can be used with a humidifier, usually heated and moist airCPAP machines with a humidifier are especially good for those who get runny noses, dry noses or dry mouths. A good CPAP machine that includes a humidifier can help you avoid these problems.  Depending on the climate where you live, a humidifier may be something you will want to investigate.

Bi-level pressure devices

Bi-level pressure devices “VPAP” or “BPAP” (variable/bi-level positive airway pressure) provide two levels of pressure: inspiratory (breathing in) positive airway pressure (IPAP) and a lower expiratory (breathing out) positive airway pressure (EPAP) for easier exhalation.  Sometimes these machines are used to help with other respiratory needs as well, not just OSA.

There are different ways these types of machines can be set up. Should you need one of these types of CPAP machines, your physician will write a prescription that specifically meets your needs.  But, as an overview, here are some of the settings you might need to know.

S (Spontaneous) – In spontaneous mode the device triggers IPAP when flow sensors detect your spontaneous inspiratory effort and then cycles back to EPAP.

T (Timed) – In timed mode the IPAP/EPAP cycling is purely machine-triggered, at a set rate, typically expressed in breaths per minute (BPM).

S/T (Spontaneous/Timed) – Like spontaneous mode, the device triggers to IPAP on patient inspiratory effort. But in spontaneous/timed mode a “backup” rate is also set to make sure you still receive a minimum number of breaths per minute should you have problems.

This is but a quick overview of OSA and CPAP Machines.  We hope this has been helpful for you, but should you have additional questions or concerns, please contact your personal representative.

Read more about mask problems at this post – Sleep Apnea Mask Problems and Solutions

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CPAP Mask Explained

What is a CPAP mask?  The CPAP mask provides the “seal” to allow the pressurized air flow into the airway, thereby holding it open.  Obstructive sleep apnea patients, who are treated with CPAP, wear a face mask during sleep which is connected to a CPAP machine through a tube.  The CPAP mask forces air into the nasal passages at pressures high enough to overcome obstructions in the airway and stimulate normal breathing. The airway pressure delivered into the upper airway is continuous during both inspiration and expiration.

People who work in sleep medicine often hear the question “what is the best CPAP mask”?  Unfortunately, there is no right answer for this.  In reality, the best CPAP mask is the one that works for you.  Like other choices in life, CPAP mask choice can be complicated and what might seem to be a good CPAP mask at first, turns out not to be the best one.  So, how do you choose?

A variety of CPAP masks exist:  nasal masks, pillows masks, full face masks, oral masks and hybrid masks.  The nasal CPAP mask typically covers only the nose, a “pillows” mask is configured with two cushions, each slightly inserted into the nostrils, a full face mask is one which covers the nose and mouth, and oral mask only covers your mouth and a oral/nasal mask covers your mouth and has nasal pillows for your nose.

Let’s take a closer look at each of these types of CPAP masks…

  • Nasal CPAP Masks
    • Nasal masks combine the minimal design of nasal pillows masks but with slightly more coverage over your nose. The nasal cpap mask cover the entire nose and is held in place with headgear, or with straps around the head. It has a silicon cushion in triangular shape, that helps make the fit more comfortable. If you have air leaks problems, it’s because the nasal mask is too big, is too old, or it has the wrong style for your face.  Facial hair can also cause air leaking with a nasal mask.
  • Nasal Pillows CPAP Masks
    • A nasal pillows mask work best if you wear glasses or read with the mask on, because some nasal pillow systems obstruct vision less than do full face masks. You can even read in bed or watch TV in bed with nasal pillows.  A Nasal Pillows CPAP mask is very easy to put on and take off at night- especially if you have to run to the bathroom. You can easily slip the nasal pillows back on with out loosing your ability to fall back to sleep quickly.  However, they may not work if you are the type of person who moves around a lot in your sleep or if you sleep on your side.
  • Full Face CPAP Masks
    • Full face masks cover more of your face to accommodate people who mostly breathe through their mouths.  It is perfect for the mouth breather, or for those patients suffering from allergies, a deviated septum or nasal congestion.  A  full face mask has a triangular shape. It seals around both the nose and mouth, and is held in place with headgear, or straps.  The full face CPAP mask also contains a  hard plastic  frame which keeps a softer inner cushion in place. This cushion lies against the face and has an important role in maintaining a good seal and comfort.  Full face masks also have head gear which consists of straps and sometimes a forehead brace.
  • Oral CPAP Masks
    • Oral CPAP  masks allow you to use only your mouth to breathe the air from CPAP.  Because it uses just your mouth only, it’s important to have heated humidification to prevent dryness of the oral tissues.  This type of mask is good for patients who breathe mostly through their mouth, who cannot use a full face mask (claustrophobia) or patients with nasal problems (nasal congestion, deviated septum, etc.).
  • Oral/Nasal CPAP Masks
    • Oral/Nasal CPAP masks cover the mouth and has nasal pillows for your nose. So, it doesn’t cause skin irritation by covering your nose.  The hybrid mask is good for mouth-breathing patients who don’t like using a chin strap or full face masks, for patients who are claustrophobic or for CPAP users with irritation on the bridge of the nose.

Almost all masks require some type of headgear to keep them in place.  In general, your CPAP mask should not fit tight on the face.  The CPAP mask should be lightweight and fit the shape and size of the nose and your facial structures.  The CPAP mask should be comfortable and not have leaks.  You may need to make some adjustments to your mask to achieve these goals.

The fact that there are many different companies that make CPAP masks, and that each company makes the “best one”, can be tiring and confusing.  So, don’t become overwhelmed with the choices.

Rather than point you to one specific CPAP mask or another, here are some thoughts and suggestions.

  • When you are first diagnosed with obstructive sleep apnea (OSA) it may be overwhelming. You have to learn how to work a CPAP machine, to review the information that is collected on the machine, to worry about humidification…….then thinking about the right CPAP mask can seem impossible.  It is OK to feel this way!  Do not be worried about asking for help. Everyone adapts to CPAP therapy differently.
  • If you have been struggling with CPAP for a while, finding a different CPAP mask option can be helpful on your road to success, ask your care provider for help with achieving your CPAP usage goal.
  • We have provided a link to the most current mask options, look to see what is available, and remember CPAP masks are always being revised and new ones come onto the market frequently.
  • Some of you might be a CPAP warrior!  Great work! You love your CPAP and mask, but still might want to look for other newer options. You might just find a new favorite!

If your mask is not working out for you, remember… you are in charge of your therapy!   The important point is that you (yes you!) can ask your CPAP equipment provider to help you get the right CPAP mask.

Before you start looking for a new mask there are a few things you need to think about:

  • the size and shape of your face – the mask has to “follow” the shape of your face or nasal orifices to minimize leaks,
  • the shape and size of your nose – to avoid the excess pressure from the mask frame (if it’s a nasal or full face mask),
  • the shape and size of your nasal openings and interior passages – if you want to use nasal pillows, these interfaces have also different shapes and sizes. Find the ones for your nose,
  • your sleep position – some masks work better for side sleeping, others for sleeping on the back.
  • other conditions – are you claustrophobic? Then a full face mask will be difficult to tolerate. Are you a mouth breather? Then nasal mask or nasal pillow will not work without the help of CPAP chin strap.
  • try CPAP mask liners, they can make living with your CPAP much easier.

If you would like professional assistance with CPAP mask selection and fitting, consider purchasing our Professional CPAP Mask Fitting service.  Tell us about your current mask… model & size, what you like about it, what you don’t like about it, what kind of problems you are having with it, etc., and one of our experienced CPAP Therapists will select three mask options for you. We’ll send you all three masks to try and your CPAP Therapist will be available to help with fitting challenges or questions via telephone or video chat.  Each product will also come with an online video showing exactly how to fit each mask.  Use all three masks and keep your favorite.  (Or keep all three at a great discount!). Learn more… (links to offer page)

Finally, a couple of ending thoughts:

  • Nothing about me, without me…… getting the right CPAP mask is your right!  Don’t settle!  Be your own advocate!
  • A good question to ask yourself is “how can I make sure that I am getting the right things that I need, when I need them?”  It is OK to ask your providers these questions and have them explain their choices.  Be empowered!
  • To quote Winston Churchill, “never, ever, ever, ever give up”; remember, there are many CPAP mask options for you!  Be empowered!  Explore, be curious and ask many questions.  It is the responsibility of the clinical professional to listen to you and provide you with what you need.

Information about CPAP mask problems…

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