Central Sleep Apnea

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Central sleep apnea (CSA) is a form of sleep-disordered breathing that occurs when the brain fails to send regular signals to the breathing muscle (diaphragm) during sleep. As a result, breathing is either not attempted or becomes more shallow than normal. This is very different than the more common obstructive sleep apnea, where the body tries to breathe but the airway remains closed or partially obstructed.

Central Sleep Apnea

Understanding Central Sleep Apnea

In a healthy patient (without sleep apnea), the brain signals the breathing muscle (diaphragm) to contract at regular intervals. The signal to breathe travels from the brain stem, down the phrenic nerve, and then to the diaphragm, causing a contraction. This contraction of the diaphragm pulls air into the lungs.

For patients with central sleep apnea, the brain fails to send regular signals to the diaphragm. This is usually because the brain has a delayed response to sensing levels of carbon dioxide (CO2) in the blood stream1. This delay in CO2 response causes an extended “pause” of breathing, ranging in duration from roughly 10 to 40 seconds. An episode may result in:

  • Sleep disturbance
  • Decrease in the body’s oxygen levels (also known as hypoxia)
  • Surge of nor-epinephrine (the body’s “fight or flight response”, which may feel like a racing heartbeat).

These events can happen multiple times per hour – sometimes as frequently as once per minute. However, these sleep disturbances are often not enough to fully wake the patient. A patient’s sleep partner may actually be more likely to identify the breathing disorder than the patient himself/herself!

Classifications of Central Sleep Apnea

An online discussion of central sleep apnea prepared by experts at Minnesota’s Mayo Clinic breaks the disease down into five types:

  1.     Primary CSA, which is the same as idiopathic CSA–the patient has no known related diseases.
  2.     Cheyne-Stokes breathing CSA, which may be a product of heart failure, stroke, or possible kidney failure.
  3.     Non-CSB CSA associated with other medical conditions, including heart and kidney problems.
  4.     High-altitude CSA, which often appears during sleep at altitudes above 15,000 feet and induces a form of CSB with noticeably shorter cycles than classical CSB. Usually the CSB disappears when the person descends to lower altitudes.
  5.     CSA induced by using certain drugs, typically opiates. May be best treated by alteration or elimination of the drug regimen.

Many patients with CSA also have heart disease, especially heart failure. Within this population, patients with CSA are at increased risk for hospitalizations and even death.

The symptoms of central sleep apnea are for the most part the same as those of obstructive sleep apnea. They include chronic fatigue, daytime sleepiness, morning headaches and restless sleep. But if the cause is a neurological disease, the CSA sufferer may also experience difficulty swallowing, voice changes, and an overall sense of weakness and numbness. A thorough sleep study with polysomnography will show whether the lapses in breathing result from airway blockage or irregular breathe signals from the brain. Many patients with CSA also have heart disease, especially heart failure. Within this population, patients with CSA are at increased risk for hospitalizations and even death.

How is CSA Diagnosed?

Central sleep apnea is diagnosed by performing an overnight sleep study. Equipment that measures airflow, oxygenation, movement of the abdomen or chest, sound (i.e. snoring), and a variety of other parameters will be used to determine whether someone has a sleep-breathing disorder. This evaluation is often done in a sleep lab.

 

Treatment Options for Central Sleep Apnea

Treatment options for Central sleep apnea include:

  • Positive airway pressure device. Various types exist, including those that provide continuous pressure (i.e. CPAP) and those that provide variable pressure (e.g. BiPAP, ASV). Notably, ASV, or adaptive-servo ventilation, is contraindicated (i.e. should not be used) in patients with chronic, symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 45%).
  • Supplemental Oxygen
  • Pharmacologic Therapy
  • Phrenic nerve stimulation: The device activates automatically each night to send signals to the breathing muscle (diaphragm) via the phrenic nerve to restore a normal breathing pattern.

Where to Learn More

Check out these resources for more information on central sleep apnea:

https://www.webmd.com/sleep-disorders/guide/central-sleep-apnea

https://www.mayoclinic.org/diseases-conditions/central-sleep-apnea/symptoms-causes/syc-20352109

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2287191/