Obstructive sleep apnea: More on CPAP

Allen Blaivas, M.D. Health Pro
  • Let's continue with some of the treatments for obstructive sleep apnea (OSA). We left off talking about continuous positive airway pressure, better known as CPAP. As we mentioned, CPAP, with the air pressure it pushes out, acts as an air splint to keep the airway from collapsing during sleep. We also touched on the fact that many patients have some difficulty, at least initially, getting used to the force of the air.


    Why can't the pressure just be lowered?


    That seems reasonable, if the pressure is uncomfortable, just lower the pressure and it will be well accepted. The problem is that CPAP is not one size fits all. Most people who are diagnosed with OSA have a separate sleep study on two nights- the first to diagnose OSA and the second to determine the best pressure for you. This second night in the sleep laboratory is called a CPAP titration study. Just like every person has their own body size and shape, and different severity of OSA, the pressures needed to keep the airway open vary from person to person. During the sleep study the polysomnographic technician, a specially trained sleep professional, is adjusting the pressure to determine at what point the apneas, or breathing pauses are eliminated.

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    If the prescribed pressure, which was determined during the titration study is just lowered indiscriminately, then it might not be adequately treating the problem. Obviously, sometimes accommodations have to be made. If the patient gives the doctor an ultimatum- "lower the pressure or I won't wear it"- most physicians will accept a slightly less than optimal pressure. Some CPAP is better than no CPAP.


    There is a relatively new device, called an autotitrating CPAP which may help avoid the necessity of the CPAP titration. The machine is able to sense an obstructive apnea and self-adjust to the pressure necessary to alleviate the airway collapse. The most appropriate usage for these machines is hotly debated in the sleep community and their exact place in treatment is still being investigated.


    I'm on CPAP, why did I only have a single night test?


    Sometimes, if the OSA is severe or the oxygen levels drop significantly during the one study, it can be "split". That means that approximately half the night is dedicated to diagnosis, while during the second half the CPAP is adjusted to the appropriate pressure.


    What are some ways to make CPAP more comfortable?


    Compared to even a few years ago, we have many, many more options in types of machines (BiPAP, flexible CPAP, autotitrating, etc.) and masks. In addition, heated humidity can be added which may help those with nasal congestion, and to decrease mouth breathing (mouth breathing causes a "leak" by releasing the air pressure from the throat, where it is needed).


    Masks come in all shapes and sizes- there are nasal, mouth and nose (full face), nasal "pillows" that fit into the nostrils, and devices that stay inside the mouth. Many patients will attempt a multitude of masks before finding one that they are comfortable with. Also make sure the hoses are long enough to allow comfortable sleep in any desired position.


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    If you tried CPAP some time ago and rejected it because you couldn't get comfortable using it, I urge you to find a dedicated sleep physician and sleep laboratory who will try different things to alleviate the problems. Most issues can be solved with trial and error.


    In my next blog I will try to cover some of the secondary options for people with sleep apnea who absolutely, positively refuse CPAP.



Published On: March 25, 2008