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Sleep Disorders

How do you know if CPAP therapy is working?



3 years ago I was diagnosed with sleep apnea following a sleep study and sleep titration study. They issued me a CPAP machine and mask. I was never able to successfully use the machine.

2 months ago, I decided to give it another try and had much better results. When I wanted to go back to get a new mask and ask some questions, however, they wanted to redo the tests. So I`ve completed the first and will go back for the second in a few weeks.

Once I`m set up with a new mask and know my CPAP machine is set to the "right" setting, how do I know that I`m no longer having sleep apnea episodes?

I live alone so there is no one to tell me what I do at night. If I wake up and the mask is still on my face, there is no guarantee the seal was complete throughout the night and that the pressure was continuous.

Is the presence or lack of tiredness the only way to know how successful my CPAP experience is each night?


I’m glad you’ve gone back to get your obstructive sleep apnea (OSA) treated and that it looks like you’ll be able to use your CPAP. Before I address your concerns about your CPAP settings, I’ll briefly discuss OSA in general and speak to the particulars of your case as we go.

OSA is a common condition, affecting roughly 5% of middle aged adults in America. Most individuals with this condition are still not diagnosed and, of those that are diagnosed, many have had it for many years prior to undergoing appropriate testing.

OSA is a condition where the airway partially or completely collapses during sleep. This results in fragmentation of sleep and, in some individuals, low oxygen level during sleep. The consequences of this condition can be serious and range from a poor quality of life (morning headaches, disabling sleepiness, poor concentration, irritability, etc) to increasing problems with blood pressure control, heart disease and strokes. Symptoms may include waking up choking or gasping at night, very loud snoring, poor and unrefreshing sleep, morning headaches and daytime sleepiness. The risk factors for sleep apnea include obesity and craniofacial abnormalities.

As mentioned above, most patients with OSA have had it for several years by the time they are diagnosed. The diagnosis requires some form of objective monitoring of sleep, typically done by an in-lab sleep study. The primary treatment for OSA is the use of a continuous positive pressure airway (CPAP) device, which is very effective at keeping the airway open during sleep. It does this by “pressurizing” the airway to prevent it from collapsing. In a large number of well-done studies, CPAP therapy has been shown to be very effective at improving a number of measures of quality of life, including daytime alertness, improved concentration and improved mood. In addition, growing data suggest that CPAP may reduce some of the medical consequences associated with sleep apnea.

So once you start on CPAP therapy, how will you know if your CPAP pressure is adequate on a night-to-night basis? Well, there are several mechanisms by which we can assess the adequacy of CPAP therapy on an ongoing basis. First, as you mention, we assess for symptoms of untreated sleep apnea at each visit. Whatever your present symptoms are without treatment (could be any or all of those mentioned above), will need to be monitored and you and your doctor should look for these as a potential sign that a pressure setting may need to be adjusted. We can also assess for adequacy of the pressure setting by using certain “smart” CPAP units (some practices use these on all patients, whereas some may use them to “spot check” patients). These units have a mechanism of detecting ongoing breathing problems in sleep and can be used to monitor the effectiveness of a given pressure setting. Checking compliance with CPAP use (hours of “pressure on time”) can also help to ensure you are getting adequate treatment. And finally, if any of these maneuvers suggest your pressure may be inadequate, a “retitration” of the CPAP therapy can be performed.

You should have the expectation of getting a good nights sleep and relief of your OSA-related symptoms. However, keep in mind that there may be nights when you do not sleep as well as you’d like and that this does not necessarily mean your CPAP is not working. A variety of factors could contribute to problems on any given night, so look for a consistent pattern before you contact your doctor with concerns.

It would probably be a good idea to discuss your case with your Sleep Specialist and make sure you have a good working relationship with him or her.

To learn more about sleep apnea or other sleep disorders, please visit the American Academy of Sleep Medicine website. In addition to information, the website contains a list of Sleep Centers across the country so that you may locate one near you. Good luck and here's to good sleep!

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Response by:

Dennis   Auckley, MD Dennis Auckley, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University