What is a CPAP?

For nearly everyone who has been diagnosed with sleep apnea1, the conversation quickly turns to possible treatment options. The most commonly used one iscontinuous positive airway pressure (CPAP)2, but what is CPAP? Take a moment to learn about the basic components of CPAP.

CPAP is the gold standard treatment for obstructive sleep apnea. It is a machine that provides a constant flow of pressurized air that works to maintain an open airway via a fitted mask. CPAP has been used to treat sleep apnea since 1981. It is also effective in eliminating snoring3. Although there are many different manufacturers of CPAP equipment, each unit consists of the same basic components:

CPAP Machine

The CPAP machine is the workhorse of your treatment. With a small motor, it takes in room air and generates the air pressure (or pneumatic splint) that is the mainstay of treating sleep apnea. Newer units are small, often smaller than a loaf of bread, and relatively quiet. Most run on electricity, but battery units are also available.

The prescribed pressure level is often determined through a sleep study called a polysomnogram4. However, it can also be set with an autotitration function that automatically determines the pressure needed to keep your airway open. In addition, it is often possible to set a pressure ramp, which allows you to fall asleep at a lower pressure that steadily increases to the therapeutic pressure that you need.

Some models have sophisticated methods of tracking your use5 with a memory card. This can help your doctor assess your compliance to the treatment.


As a comfort measure, it is possible to add humidity to the air that is delivered with an attached humidifier. This generally consists of a plastic reservoir that can be filled with distilled water. As the air passes over the water, direct evaporation occurs. The humidifier may be an integrated part of the larger CPAP machine unit or it may be separated by a short length of plastic tubing.

Heated humidifiers are also available. These include a small “hot plate” that increases the amount of evaporation and subsequent moisture put into the inhaled air.

It is very important to keep this water reservoir clean,6 as it can be a source of recurrent respiratory infection or even mold.

CPAP Hose or CPAP Tubing

The next component that is standard to all CPAP machines is the CPAP hose or tubing. The CPAP tubing is typically made of a flexible plastic, allowing some degree of movement. Frankly, it resembles the extension hose on a vacuum cleaner. It is typically about six feet long. However, with an adapter or connector, it is possible to have two lengths of tubing linked together. You should be cautious about extending the hose too much as it may decrease the pressure that is ultimately delivered to your face mask. If you don’t have a humidifier, the CPAP tubing connects directly to the machine. Otherwise, the humidifier will intervene. On the other end, you will connect your mask.


The CPAP mask is, undeniably, the most important part of your experience with CPAP. It is where the “rubber meets the road” and it will make you fall in love with your CPAP machine — or hate it. The most common mask fits over the nose, but some consist of nasal pillows7 that sit in the nostrils or even interfaces that sit over the nose and mouth. There are many CPAP mask styles available, which makes it all the more important in how to choose one8.

CPAP can be an effective treatment for obstructive sleep apnea, but it only does you good if you use it.