What is Central Sleep Apnea?

Central sleep apnea (CSA) is a type of sleep disorder that causes your breathing to repeatedly stop and start during sleep. It’s associated with significant complications, including frequent nighttime awakenings, excessive daytime sleepiness and an increased risk of problems associated with the heart and circulatory system.^[1] If you suspect you or a loved one has central sleep apnea, see your health care provider right away for diagnosis and next steps.

Causes of CSA

Breathing is controlled by the autonomic nervous system, a part of the nervous system that unconsciously controls bodily function such as breathing, heart rate and digestion. Under normal circumstances, when the brain senses the need for a breath, it sends signals to the diaphragm and intercostal muscles to contract and relax at regular intervals. With central sleep apnea, however, this process is disrupted because the brain fails to send those signals. CSA may be caused by a number of important factors including:^[2]

• Cheyne-Stokes breathing – a distinct breathing pattern characterized by progressively deeper and faster breaths followed by a gradual decrease that leads to a temporary cessation of breathing (apnea). Most commonly associated with congestive heart failure (CHF) and stroke.
• High altitude periodic breathing – exposure to very high altitudes where less oxygen is available in the air may cause a Cheyne-Stokes type of breathing pattern.
• Complex (mixed) sleep apnea – a combination of both types of sleep apneas: obstructive sleep apnea (OSA), ), in which you cannot breathe because of an upper airway obstruction, and CSA.
• Medical condition-induced CSA – CSA caused by certain medical conditions that are not associated conditions, like heart failure and stroke, which with the Cheyne-Stokes variety of breathing.
• Idiopathic CSA – CSA caused by an unknown source.
• Drug-induced apnea – certain types of medications, particularly opioids (morphine, Oxycodone, Codeine, etc.) can cause an irregular breathing pattern including an increase and decrease in a regular pattern or a complete, temporary cessation of breathing.

Central Sleep Apnea Symptoms

Many people with central sleep apnea have no idea that they have it, and partners identify it more often than it is self-identified. As such, it is important to be aware of the symptoms of CSA, just in case. The symptoms of central sleep apnea include:²

• Loud snoring accompanied by abrupt awakenings, shortness of breath and snorting or gasping for air (often witnessed by a partner or bed mate)
• Shortness of breath that is relieved by sitting in an upright position
• Difficulty staying asleep (one type of insomnia)
• Excessive daytime sleepiness (hypersomnia)
• Difficulty concentrating
• Chest pain at night
• Mood changes
• Morning headaches
• Other observed episodes of abnormal breathing patterns during sleep

Keep in mind that, while snoring is more often associated with obstructive sleep apnea, snoring can be present with central sleep apnea, too. Look for other symptoms, in addition to snoring, to help assess your potential risk.

Complications Associated with Central Sleep Apnea

Central sleep apnea is a serious medical condition associated with potentially significant complications. These complications can put your health at further risk if your CSA continues untreated. Complications can include:

• Cardiovascular complications: People with central sleep apnea experience sudden drops in blood oxygen levels (hypoxemia) when their breathing is halted, which can have negative effects on your cardiovascular health. These problems are compounded if there is any history of or underlying heart disease, and your risk of irregular heart rhythms can increase.
• Fatigue: Because central sleep apnea disrupts your sleep, people with CSA are often severely tired, experiencing daytime drowsiness, difficulty concentrating and irritability as a result. If you fall asleep at work or you are having trouble concentrating on everyday activities like driving or watching TV, it may be because of CSA.

Are You at Risk for Central Sleep Apnea?

Though anyone can develop central sleep apnea, some populations are at a higher risk of developing CSA. The following factors may put you at risk for central sleep apnea:²

• Being male
• Being an older adult, especially older than 65 years of age
• Having atrial fibrillation (A-fib) or congestive heart failure (CHF)
• History of stroke, brain tumor or structural brain lesion
• Sleeping in high altitude
• Use of opioids
• Use of continuous positive airway pressure (CPAP) for obstructive sleep apnea (sometimes causes CSA)

Central Sleep Apenea Diagnosis

Central sleep apnea is diagnosed using a test called a polysomnography, commonly referred to as a sleep study.²  During a sleep study, you are connected to equipment that monitors your overnight breathing, your heart, your lung activity, your brain activity, your blood oxygen levels and your arm and leg movements. If you are diagnosed with central sleep apnea, you may also be asked to participate in a split-night sleep study, during which you are monitored for the first half of the night, then awakened so you can receive positive airway pressure for the remainder of the night.

Following the results of your polysomnography, you may receive other tests to identify problems with your heart or your brain, or to identify contributing conditions. 

Central Sleep Apnea Treatment

Treatment of central sleep apnea includes treating both the causes of the CSA to attempt to eliminate it. Treatments for CSA may include the following:²

• Addressing coexisting medical conditions, like heart failure, may help resolve CSA.
• Reducing opioid consumption: Gradually reducing your dose of this type of medication may help eliminate CSA.
• Using CPAP: Usually the first-line treatment for CSA, CPAP involves wearing a mask over your nose while you sleep that is attached to a hose and small pump that delivers continuous pressure to help keep your airway open.
• Adaptive servo-ventilation (ASV): ASV adjusts the amount of pressure with every breath instead of providing the continuous pressure used with CPAP and may also deliver a breath when breathing is paused for a certain amount of seconds. Sometimes used when CPAP is ineffective.
• Bi-Level Positive Airway Pressure: Delivers a higher amount of pressure when you breathe in and a lower amount of pressure when you breathe out. More tolerable than CPAP for some people, especially people with lung diseaseslike COPD.
• Supplemental oxygen provided during sleep may help relieve CSA.
• Certain medications that stimulate breathing, such as acetazolamide (Diamox) and theophylline (Theo-24, etc.), may be helpful for those with CSA.

How CSA Differs from Other Types of Sleep Apnea

Central sleep apnea is characterized by the breathing center in the brain failing to send a signal to the diaphragm and intercostal muscles to breathe. So how does CSA differ from OSA, and how does one wind up with both types of sleep apnea?

Obstructive sleep apnea – the most common type of sleep apnea, OSA occurs when the throat muscles sporadically relax during sleep causing a partial or complete blockage of the airway. This leads to episodes of hypopnea (abnormally slow/shallow breathing) and complete apnea (cessation of breathing). It differs from CSA because it’s caused by a physical obstruction of the airway and has nothing to do with brain activity and the autonomic nervous system.^[3]

Complex or mixed sleep apnea is a combination of both types of sleep apneas: OSA and CSA. It has been suggested that some OSA patients treated with CPAP also develop CSA. In fact, in 2006, researchers from the Mayo Clinic conducted a study using 223 OSA patients and found that 15% of them also had CSA. During CPAP treatment their airways were successfully “splinted open and free from obstruction,” but they continued to have difficulty breathing during sleep. The study revealed that their symptoms of OSA shifted to symptoms of CSA while undergoing CPAP treatment for OSA.^[4]

What to Do If You Are Diagnosed with Central Sleep Apnea

Talk to your health care provider about how to best treat your central sleep apnea. If you are prescribed supplemental oxygen therapy, Inogen may be able to help you with your CSA treatments. Contact our Inogen Oxygen Specialists to find out more today.

_{[1] Eckert, D. J., Jordan, A. S., Merchia, P., & Malhotra, A. (2007). Central Sleep Apnea: Pathophysiology and Treatment. Chest, 131(2), 595–607. http://doi.org/10.1378/chest.06.2287}

_{[2] Mayo Clinic. Central Sleep Apnea. August 7, 2017.}

_{[3] Mayo Clinic. Obstructive Sleep Apnea. August 2, 2017.}

_{[4] Wang, J., Wang, Y., Feng, J., Chen, B., & Cao, J. (2013). Complex sleep apnea syndrome. Patient Preference and Adherence, 7, 633–641. http://doi.org/10.2147/PPA.S46626}