Mixed apnea is a combination of central and obstructive apnea. Most people with sleep apnea probably have some form of mixed apnea. In fact, some sleep researchers believe that most, if not all, obstructive sleep apnea has a central apnea component and that some abnormality in the breathing reflex in the brain usually accompanies the development of obstructive apnea.
Others interpret the cause and effect that occur in mixed apnea a little differently. They point out that as a person gasps and recovers from an obstructive apnea event, she typically “overbreathes”, which results in an unusually low level of carbon dioxide in the blood. In turn, this lower carbon dioxide level is enough to trigger a central apnea event, thereby producing mixed apnea. The more severe the obstructive apnea, the more severe the “overbreathing” is likely to be and the more obvious the central apnea component could be.
In any case, whatever the actual cause and effect in mixed apnea, for treatment purposes, the obstructive apnea is usually treated first. Once the breathing obstruction is treated, the central apnea will often disappear, or at least lessen to the point where it does not require treatment.
