Is it time for a CPAP checkup?

A man sleeps while wearing a CPAP mask for sleep apnea.

Ever since your obstructive sleep apnea diagnosis, you've tried to use your continuous positive airway pressure (CPAP) machine faithfully each night. Hopefully, it has restored your ability to sleep without snoring, coughing, choking, or suffering dozens of pauses in breathing per hour. And perhaps it helps you feel more alert, awake, and productive, and has begun to lower the risk of dangerous consequences related to sleep apnea, such as high blood pressure, heart disease, stroke, and depression.

But the gentle hum of the CPAP device doesn't guarantee that the therapy is working effectively; like a sensitive medication regimen, it needs to be assessed and monitored regularly.

What is CPAP therapy?

CPAP therapy prevents your upper airways from being blocked by throat muscles that relax too much during sleep. The therapy involves a small bedside compressor that pumps a forceful stream of air through a tube and into your nose via a mask you wear all night. A standard CPAP machine delivers a fixed air pressure, while an auto-CPAP machine automatically adjusts pressure based on your varying needs throughout the night, such as when you change position or shift into a new sleep stage.

Your health care provider must prescribe the therapy. You then obtain the system through a medical equipment supplier. A technician from the supplier will work with you to find the right mask, set the specified air pressure settings to keep your airways open without disturbing your sleep, and answer ongoing questions about using the system.

You can control the temperature and humidity of the air entering the mask. Additionally, you can choose how fast the air pressure increases: "You can set it to ramp up over five minutes or 45 minutes, or select the 'auto-ramp' setting and have the machine adjust the pace automatically based on your breathing," explains Dr. Karen Lee, a neurologist and sleep medicine specialist at Harvard-affiliated Massachusetts Eye and Ear.

Initial check-ups

For CPAP therapy to be covered by insurance, you're required to see your health care provider 30 to 90 days after you start using the system. "The clinician always needs to ensure that the CPAP has improved and hopefully resolved your sleep issues," Dr. Lee says, "and what can be complicated is that you may not be aware of some of your sleep issues. For example, sleep apnea often increases the frequency of nighttime urinations, grinding or clenching your teeth, and night sweats. The clinician needs to ask appropriate questions to understand if your sleep is optimized while using CPAP."

At your first check-up, your provider will review data that the machine has been collecting. "The machine tells us when you're using the device and estimates how many apnea episodes you're having per hour, when you're struggling to breathe, and whether air is leaking out your mouth or around the mask unintentionally," Dr. Lee says.

Based on that information and your own observations, your clinician might prescribe a higher or lower air pressure. You might need to go back for additional visits and adjustments until the kinks are ironed out, which can take a few months. You may even require an overnight study in the sleep lab while using CPAP to help clarify any issues.

All PAP therapies need regular evaluation

Continuous positive airway pressure (CPAP) therapy is just one type of positive airway pressure (PAP). Other types include

auto-adjusting positive airway pressure (APAP), which provides a range of preset pressures throughout the night
bilevel positive airway pressure (BiPAP), which provides two different preset pressures — a more powerful one when you inhale and a less powerful one when you exhale
adaptive servo ventilation (ASV), an advanced device that provides pressure based on breathing patterns throughout the night.

All these therapies need periodic assessment to determine how well they're working and whether the settings need adjustment.

Additional check-ups

Once the CPAP system is working for you, you'll need to have it re-evaluated at least once a year to see if the air pressure needs to be adjusted. These continuing follow-up appointments are important for many reasons.

Data updates. Dr. Lee says that CPAP machines provide only estimated information, which sometimes is inaccurate. She needs to compare it with insights from a patient visit to determine if the CPAP really is helping.

Worsening sleep apnea. Everything sags as we get older, even the airway, which causes the disease to advance over time.

Weight loss or gain. Gaining weight can make sleep apnea worse; losing weight can make it better or even make it disappear. Either could potentially affect the pressure settings.

Treatment side effects. Dr. Lee says that the brain sometimes reacts to CPAP in a way that creates another type of apnea. In that case, the settings or the actual device would need to be changed.

Other sleep issues. "We need to make sure all of your sleep needs are being addressed," Dr. Lee says, "especially if you have other sleep disorders such as insomnia, restless legs syndrome, or sleepiness, despite effective CPAP treatment."

Missed check-ups

Unfortunately, many people don't get regular CPAP check-ups. If you're among them, it could be that your clinician never told you that you need periodic assessments. "While any health care provider can prescribe the therapy, they don't all know how to adjust it optimally or that they should evaluate it regularly," Dr. Lee says.

Or you might not be getting CPAP check-ups because

you feel better and don't think you need additional assessments
you don't think the therapy is effective and have given up on it
your schedule is too hectic
you assume (mistakenly) that the medical equipment supplier is monitoring your health.

When to call the expert

If you've never had your CPAP use evaluated or haven't done so in a long time, Dr. Lee advises making an appointment with a sleep specialist or with the expert who prescribed the therapy.

Dr. Lee also recommends calling your clinician any time new health problems or symptoms affect sleep. "Come see me if you start snoring again or you're tired despite using the machine," she says. "If you have questions, they need to be asked." For more information, check out the Harvard Special Health Report Snoring and Sleep Apnea.