CPAP is supposed to treat sleep apnea, so when people hear that it may actually cause the condition, they are skeptical. For most people undergoing treatment with CPAP, the thought that it might cause central sleep apnea (CSA) is dismissed as an illogical rumor, as you can see from responses to this forum post. However, this is a very real issue, and it’s important that people understand it before they decide on the treatment for their obstructive sleep apnea (OSA).
The relationship between CPAP and CSA is very complex, and it’s not fully understood, but it is real. Here are some theories about the relationship so you can have a clearer grasp of the issue.
By Treating OSA, CPAP Reveals CSA
This is one theory that has been forwarded to account for the fact that some people start showing CSA after they get treatment with CPAP. Basically, some postulate that CSA was present all along, but it was hidden under the much more severe OSA. When OSA was treated, the CSA could be seen more plainly.
Too High CPAP Pressure Leads to CSA
In this theory, when a CPAP machine is set too high, it forces so much air into the lungs that it prevents the CO2 level from reaching the level necessary to trigger exhalation. One researcher has noted that properly titrating (adjusting) CPAP eliminates CSA in nearly half of patients.
There Is Another Type of Sleep Apnea That Doesn’t Respond to CPAP
Another theory is that there is a third type of sleep apnea, called complex sleep apnea syndrome, which isn’t just OSA and CSA together, but a completely different type altogether. People in this group are said not to respond to CPAP. Despite the best adjustment possible of CPAP, patients continue to have as many as 60 apneic events per hour. Other research confirms that people with this complex sleep apnea syndrome get poor results from CPAP.
Some Patients May Respond to CPAP with CSA
In this theory, some patients with certain high-risk factors may develop CSA as a result of CPAP treatment. These patients are likely to have higher apnea counts, may have already had heart failures, and may have a high mixed sleep apnea index.
The Best Treatment Is Unknown
At this point, the prognosis for patients who fit into this category is not well known. It doesn’t seem good, with the risk of repeated heart failures ultimately leading to cardiovascular mortality. We don’t know whether oral appliance therapy will work at all for these patients, and we keep looking for the next treatment option that will give us a good way to treat patients who fit in this category.
To learn more about oral appliance therapy call the TMJ Therapy & Sleep Center of Colorado at (303) 691-0267.