Central sleep apnea (CSA) is characterized by pauses in breathing during sleep due to a signal disruption from the central nervous system. Typically, the episodes last for 10-30 seconds (or longer) and can be intermittent in nature or happen in cycles throughout the night. Central sleep apnea is associated with lower oxygen saturation levels, a condition called hypoxia or hypoxemia, which can lead to serious health complications.
One of the most common central sleep apnea causes is an imbalance in the body's levels of oxygen and carbon dioxide, both of which should stay fairly constant when the body is at rest.
There are chemoreceptors in the body, which are governed by oxygen and carbon dioxide levels in the bloodstream. These chemoreceptors send signals to the brain to tell it when to open the throat and other breathing airways, as well as to move the muscles associated with respiratory efforts. Regular respiration allows the body to remove excess, harmful carbon dioxide from the lungs and bloodstream.
However, in central sleep apnea, the chemoreceptors that lie within the brain dysfunction during sleep, failing to give the brain a signal to inhale. This causes several cycles of breath to be missed, leaving the body with an increase in carbon dioxide levels.
Another central sleep apnea cause is an issue with respiratory regulation. The brain and heart normally work together to keep a balanced level of oxygen and carbon dioxide in the bloodstream. However, the heart and brain may differ in what each organ considers “normal” inhalation and exhalation cycles.
Central sleep apnea causes the neurological centers in the brain that are responsible for breathing cycles to fail to react fast enough to keep the respiratory rate even and unlabored. This causes the respiratory rate to fluctuate between central sleep apnea and hypopnea episodes throughout the night.
During the breathing pauses, the individual makes no efforts to start breathing again, the chest does not move, and the muscles do not relax or contract. Individuals will wake up and not be able to immediately start breathing again, leading to a feeling of panic and cognitive dysfunction. These symptoms are associated with excess carbon dioxide levels in the blood.
Cheyne-Stokes respirations are characterized by periodic breathing with regular episodes of alternating between central sleep apnea and rapid breathing, causing extreme fluctuations in oxygen and carbon dioxide levels in the bloodstream.
This is a condition found in patients with congestive heart failure and is not restricted to sleep, but can happen during waking hours as well. It is also common in patients with kidney failure and stroke. It is believed that treatment of the failing organ leads to a resolution of Cheyne-Stokes respirations.
A central sleep apnea diagnosis can be completed by licensed physicians. The first step in a central sleep apnea diagnosis requires an examination, which generally includes the individual staying overnight in a sleep laboratory to receive a sleep study, or polysomnography, administered by a technician.
Periods of breathing cessation are measured in frequency during the sleep study, which will allow the technician to help determine what type of sleep apnea is present.In central sleep apnea, the interruption in breathing is associated with physically being unable to restart the cycle. A polysomnogram will show the relation between the cessation of airflow through the nose and mouth, as well as the absence of muscle movement in the rib cage and abdominal area.
Since central sleep apnea is frequently associated with heart, lung, or kidney diseases, there are other tests that are done with polysomnography, including:
After diagnosis, a licensed physician will provide a few different options for central sleep apnea treatment.
Continuous positive airway pressure (CPAP) treatment is usually reserved for those with obstructive sleep apnea, rather than those with central sleep apnea. The patient wears a face mask that is connected to a machine, which provides pressured airflow into the breathing passages. The device compresses the room air at a constant level so that the airway does not collapse, which is typical in OSA cases. While it is usually at a higher level, it stays low enough so that the individual can easily exhale on their own.
BiLevel Positive airway pressure (BiPAP) is much more common in central sleep apnea treatment . It differs from CPAP (continuous positive airway pressure) in that it is not at a constant high pressure, but is set at two separate pressure settings: IPAP (for inhalation) and EPAP (for exhalation). This allows the user to have a more normal respiratory rhythm. The lungs are inflated at a regular interval, which is a measurement that includes both the duration of a single breath and the normal breathing rate. The BiPAP levels are programmed by the diagnosing provider.
Adaptive Servo Ventilation (ASV) is a newer technology that is being used for central sleep apnea treatment. . ASV is similar to CPAP, but uses a different algorithm.
This is more of a lifestyle change, rather than a treatment, but recent studies have shown that changing your sleep position at night may have an impact on the severity of one type of central sleep apnea : Cheyne-Stokes.
Positional changes are known to affect the severity of obstructive sleep apnea. However, recent research has looked at how these changes may affect central sleep apnea patients as well. There was an increased severity of Cheyne-Stoke respirations when patients slept in the supine position (lying on their back). Otherwise, patients with central sleep apnea and no known cardiac conditions were not seen to have any symptom changes related to position during sleep.
There are relatively new treatments that use programmed electrical impulse to stimulate the diaphragm for central sleep apnea treatment. They physically resemble cardiac pacemakers. However, they are attached to the phrenic nerve.
© 2020 American Sleep Association.