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What Is an APAP Machine?

Automatic positive airway pressure (APAP) machines were first introduced in 19961 as a more advanced alternative to CPAP machines in the treatment of sleep apnea. Both machines are used to deliver pressurized air for better breathing during sleep. However, while CPAP delivers air at a single pre-programmed pressure, APAP allows pressure to increase and decrease over a set pressure range. 

We’ll dive more into APAP machines, including why they might be preferable to CPAP in certain cases and who experts may recommend one for. Ultimately, your own healthcare provider will be the one to decide what type of positive airway pressure machine you should get, but if you’re curious to know more about APAP therapy, we’re here to help.

What Is an APAP Machine Used For?

APAP machines are used to treat obstructive sleep apnea (OSA), which is a sleep disorder in which the muscles around the throat relax while sleeping, which can obstruct the upper airway. This can lead to brief lapses in breathing before the brain briefly jolts the sleeper awake to take a breath. The air delivered by the APAP forces the airway open, allowing the patient to breathe properly and sleep better. 

How an APAP Machine Works

An APAP machine consists of a small unit that houses an air compressor, a hose, and a mask. The machine is programmed to be able to deliver air within a set range of pressure that’s determined by the severity of the patient’s OSA. This is calculated during the diagnostic process, which usually involves an overnight study at a sleep center. 

The APAP machine is designed to deliver the amount of air required to keep the airway open2. It does this by constantly monitoring breathing, decreasing pressure when breathing is normal, and increasing pressure when a gap in breathing is detected (apnea episode). 

The rate at which the pressure changes depends on the model of the machine, as different manufacturers use different algorithms3. Some machines decrease air pressure soon after an apnea episode, while others remain at the higher pressure for longer. Your healthcare provider should be able to suggest the best type of APAP for your individual needs. 

How Does an APAP Machine Know You Have Stopped Breathing?

APAP machines contain pressure sensors that measure airway resistance. Airway resistance is caused by an obstructed airway4, so if the airway has closed enough to prevent breathing, there will be a higher resistance. 

The machine increases air pressure in line with resistance to force the airway open, allowing the patient to breathe again. Once resistance decreases, the APAP will decrease the pressure until it detects another apnea event.

APAP Machine vs. CPAP Machine

APAP and CPAP machines have a similar setup, featuring a small motorized unit that filters and pressurizes air, which is then delivered via tubing and a mask. Many machines also contain a humidifier, to add moisture to the air that’s delivered. However, the difference between them is that CPAP machines are programmed to deliver a set level of pressure throughout the night, and an APAP can adjust pressure as required. 

APAP machines typically cost more than CPAP devices because they feature more complex technology. Outside of insurance, a CPAP will typically cost between $500 and $1,000, while an APAP may cost $600 to $1,600.

More: APAP vs. CPAP

Who Should Use an APAP Machine?

People who struggle with the fixed pressure of a CPAP may prefer an APAP. 

Also, research shows that APAP may be more effective than CPAP in cases of patients with positional OSA5, which is when apnea severity changes depending on the sleeping position. This same study found that some patients experienced an increase in dry mouth on CPAP due to the fixed air pressure drying up saliva and that switching to APAP resolved this.5 

Changes in body weight can affect the severity of sleep apnea, so people whose weight frequently fluctuates may also benefit from APAP6.

Who Should Use a CPAP Machine?

CPAP machines are the most common form of treatment for OSA7 as they’re cheaper and more widely available, so CPAP could be the first type of machine offered to you. If treatment is effective and tolerated, you will likely remain on CPAP as most insurers won’t pay for a more expensive machine if it’s not necessary. 

Some light sleepers8 may prefer the consistent pressure of CPAP if they’re likely to feel disturbed by the fluctuating pressure of APAP. 

APAP Machine Benefits

An APAP delivers the lowest possible effective pressure, which some people find less disturbing than the constant pressure of a CPAP.6 A 2019 systematic review showed that many people experience less pressure discomfort and less nasal irritation9 with APAP, and some patients also reported that APAP machines were quieter.

Potential APAP Machine Drawbacks 

While some people prefer the adjusting pressure of an APAP, some patients might experience discomfort or disturbed sleep due to the fluctuating pressure. Some users may also find apnea events returning once the pressure has decreased.9

APAP machines are sensitive to air leaks, as mentioned in a 2022 study10 that saw increased leakage over time. In the case of significant air leaks, APAP machines may not be able to detect apnea events accurately, which may result in them delivering incorrect levels of air pressure. Researchers hypothesize that incorrect pressure increases can lead to some patients developing central sleep apnea.9 

Additionally, a 2016 randomized clinical trial11 on 322 patients with OSA found that CPAP machines were more effective at lowering blood pressure over a 24-hour period than APAP machines.

What to Do if You Think You Need an APAP Machine 

Symptoms of sleep apnea12 include gasping for air during sleep, loud snoring, waking up with a headache and/or dry mouth, low mood and irritability, extreme daytime sleepiness, and difficulty focusing. However, signs of sleep apnea may overlap with other medical conditions, so it’s important to get checked out by your doctor to confirm a diagnosis. If they suspect you have sleep apnea, they’ll likely recommend you take a sleep study, either at home or in a clinic. 

If you receive a sleep apnea diagnosis, you’ll receive a prescription for the appropriate treatment, which may consist of a CPAP, APAP, or other PAP device.

How to Buy an APAP Machine 

You must have a prescription from a healthcare professional to buy an APAP machine. Once you have your prescription, you can purchase an APAP machine yourself or through insurance if they cover an APAP. When going through insurance, most insurers will have an approved list of suppliers. You cannot buy an APAP if your prescription is for a CPAP. 

Frequently Asked Questions

What is an APAP machine?

An APAP is a form of sleep apnea treatment that delivers pressurized air to the patient while they sleep to help keep their airway open. The APAP is programmed with a set pressure range determined by your prescription, and the pressure can change throughout the night based on your breathing patterns, which are monitored by a sensor.

Is an APAP machine better than a CPAP machine?

APAP machines are more complex and often more expensive than CPAP machines because they provide auto-adjusting air pressure rather than the fixed air pressure of a CPAP. However, neither machine is better than the other; it all depends on the individual needs of the patient.

Most people with obstructive sleep apnea will start on CPAP, and those who are sensitive to pressure changes may prefer the fixed pressure of a CPAP. However, people who aren’t successful with a CPAP may prefer APAP, and patients with positional OSA may find an APAP more effective.5

If you’re struggling to sleep with your PAP device, always speak to your healthcare provider. They may be able to suggest machine adjustments, a different type of machine, or an alternative to PAP therapy.

Where can I buy an APAP machine?

As long as you have a valid prescription, you can buy an APAP machine online or at a brick-and-mortar store. Some people prefer to shop in person to try on different mask styles and find one that’s more suited to them. However, some online retailers offer AI mask-fitting technology, which can be useful for people who cannot easily access a store.

You can also opt to go through your health insurance if they will help cover your APAP device.

Lisa Bowman

Lisa Bowman


About Author

Lisa is a content writer for Sleep Advisor, which combines two of her greatest passions – writing and sleeping. She can also be found writing about fitness, sustainability and vegan food.

Combination Sleeper


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