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Sleep Disorders

Complex sleep apnea

10/19/2007

Question:

I recently was retested for sleep apnea. I have used a cpap for six years. The cpap treatment hasn`t worked for the last 1&1/2 years. My Obstructive sleep apnea on the new test had changed from an 11 to a 7. REM sleep was normal and then I presented with central sleep apneas before awakening to go to bathroom. The technician told me that he would recommend treatment with oxygen, probably with out cpap during sleep. My concerns are that the latest studies show that complex sleep apnea can worsen with oxygen and that the best treatment is the new ASV cpap machine.

I did try sleeping with oxygen and it hasn`t helped. I fight staying awake from the moment I get up in the morning until I go to bed and feel weak and unrested no matter how much sleep I get.

Answer:

When Sleep Physicians speak of sleep disordered breathing, they are generally referring to sleep apnea. Sleep apnea is a condition where individuals have problems with breathing in their sleep - usually due to intermittent episodes of not breathing or reduced breathing effort. Sleep apnea can generally be categorized into 2 different forms - obstructive sleep apnea and central sleep apnea. However, there is a relatively recent form of sleep apnea, called complex sleep apnea, which has been recognized and described. Unfortunately, there is some confusion over the different definitions and it sounds like this may be the case in your situation. As obstructive sleep apnea is much more common than central sleep apnea, I will discuss that first and then follow-up with brief discussions on central apnea and complex apnea. Obstructive sleep apnea is defined as repetitive episodes of airway narrowing or collapse during sleep. During sleep, the muscles supporting the upper airway in the back of the throat tend to relax. When individuals with a narrowed airway to start with fall asleep, this muscle relaxation may be enough to cause significant narrowing or collapse of the tissue in the back of the throat. A narrowed airway is most commonly the result of being overweight as fatty tissue tends to deposit in the tissues of the airway. Other causes of a narrowed airway may include large tonsils (a very common cause of sleep apnea in children), a large tongue, and abnormal jaw anatomy or nasal anatomy. When the airway collapses in obstructive sleep apnea, the brain and body protect themselves by making the individual briefly awaken (most people who do this are not aware of this happening) and opening their airway to allow for normal breathing. Unfortunately, as they fall back asleep, the process of airway closure tends to repeat over and over. These recurrent awakenings fragment or break up sleep, resulting in poor sleep, a lack of feeling refreshed after sleep and daytime sleepiness.

Other symptoms of obstructive sleep apnea may include morning headaches and restless sleep. Loud snoring often accompanies the sleep disordered breathing. If you are experiencing these symptoms, it is best to have a full sleep evaluation. Not only does the poor sleep affect your quality of life, but obstructive sleep apnea has now been linked to numerous other problems if it goes unrecognized and untreated for years and years. Most concerning of these conditions are high blood pressure and cardiovascular disease (for example stroke and heart disease).

Obstructive sleep apnea is treatable by a number of methods and the type of treatment best suited for each individual depends on a number of factors. The first line therapy for most patients with OSA is continuous positive airway pressure, or CPAP. CPAP therapy is the first line therapy because it works very well and, with patience, motivation and close follow-up, most patients can get used to using CPAP on a nightly basis. In a large number of well-done studies, CPAP therapy has been consistently shown to be effective at improving a number of measures of quality of life, including daytime alertness, improved concentration and improved mood. Individuals with OSA who can successfully use their CPAP generally feel better! In addition, growing data suggests that CPAP may reduce some of the medical consequences associated with OSA. In some individuals, CPAP pressure settings may change over time and require adjustments in order to continue to control the OSA.

Central sleep apnea is much less common than OSA. As opposed to the airway collapsing as in obstructive sleep apnea, in central sleep apnea, there is generally a lack of effort to breath during sleep. The brain fails to send the signal to breath and individuals will experience a lack of breathing for several seconds at a time before resuming normal respirations. This condition may be seen in individuals who have had strokes or who have advanced heart failure, though for some individuals, no cause is identified. Unlike OSA, those with central sleep apnea often complain of trouble sleeping and insomnia. They may feel tired and fatigued as a result. A number of treatment options are available for central sleep apnea as well and will depend upon the associated conditions and other clinical factors. Some of these treatments include CPAP or oxygen therapy. However, each of these treatments is not uniformly effective and thus therapy really needs to be tailored to each individual.

Complex sleep apnea is, in some respects, a mix of OSA and central sleep apnea. This is condition is defined based on certain characteristics of an individuals sleep during a sleep study. In complex sleep apnea, there is a diagnosis of OSA during monitored sleep. However, when placed on CPAP therapy to eliminate the obstructive events, the individual develops a central sleep apnea pattern. In other words, the CPAP is effective at keeping the airway open, but now the brain fails to send the signal to breath. As such, complex sleep apnea can only be diagnosed if you have OSA on a diagnostic sleep study and then central sleep apnea while being monitored on CPAP.

The significance of having complex sleep apnea is not entirely clear. It is not known if this represents a different type of sleep apnea or something we see on a single night sleep study that resolves over time. Some individuals with this condition can be controlled with CPAP, others with Bipap and some need the newer type of device called adaptive servo ventilation (ASV or VPAP). Oxygen is not considered a treatment for this condition as it is generally not a treatment for OSA. I recommend discussing your sleep study result with your Sleep Specialist and letting them know about your poor response to oxygen therapy. Further evaluation may be needed to determine the treatment best suited for you.

If you would like additional information regarding sleep and sleep disorders, you can obtain it on the American Academy of Sleep Medicine website. This website also contains a list of Sleep Centers across the country so you can locate one near you if need be. Good luck and here's to better sleep!

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Response by:

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