What is central sleep apnea (CSA)? Symptoms, causes, and treatment options

You’re probably familiar with obstructive sleep apnea (OSA), but have you heard of central sleep apnea (CSA)?

Although it’s just as serious as obstructive sleep apnea, central sleep apnea is less common and less well-known.

In this article, we’ll explain what central sleep apnea is, how it differs from other forms of sleep apnea, its causes, treatment options, and more.

What is sleep apnea?

“Sleep apnea” is a broad term that can describe any disorder in which breathing is repeatedly interrupted during sleep. If left untreated, this disrupted breathing can lead to a variety of serious negative short-term and long-term consequences.

There are four types of sleep apnea:

• Central sleep apnea occurs when the brain “forgets” to stimulate the diaphragm during sleep. As a result, a person who experiences central sleep apnea events does not breathe or breathes less deeply than normal.¹
• Obstructive sleep apnea occurs when a narrowing or obstruction prevents air from flowing freely. Obstruction can be caused by a person’s anatomy, or by the way their neck and chest muscles relax during sleep.²
• Mixed sleep apnea refers to disrupted breathing that is both central and obstructive. In most cases, it begins as central and an airway obstruction follows.¹
• Complex sleep apnea typically refers to central events that arise only after positive airway pressure (PAP) therapy is applied.⁴

Sleep apnea is typically diagnosed based on the kind of event a person predominately experiences, which means that it’s common for people to have both central and obstructive sleep apnea.³

What is central sleep apnea?

To understand central sleep apnea, it’s helpful to know how breathing normally works during sleep.

When people without CSA sleep, their brain sends a signal to the diaphragm, or “breathing muscle,” every few seconds. This signal travels from their brain stem down their phrenic nerve and then to the diaphragm, causing a contraction. This contraction pulls air into the lungs, causing a breath.

When people with CSA are sleeping, their brain “forgets” to signal the diaphragm. As a result, there’s an extended pause in breathing—often lasting between 10 and 40 seconds. These events can result in:

• Sleep disturbance
• Decreased oxygen levels (also known as hypoxia)
• A surge of norepinephrine (the body’s “fight or flight response,” which may feel like a racing heartbeat).

Central sleep apnea events can happen multiple times per hour—sometimes as frequently as once per minute.

Notably, “pure” central sleep apnea, in which no breathing disruptions are caused by obstruction, is uncommon.

What does central sleep apnea feel like?

Because people with CSA are asleep when their breathing is disrupted, they may not even know they have it. In fact, their sleep partners are more likely to identify sleep apnea! If you or your loved one is experiencing these symptoms, central sleep apnea may be the cause^2,5:

• Long pauses in sleep at night
• Chronic fatigue
• Excessive daytime sleepiness
• Brain fog or cognitive impairment
• Inability to fall asleep or get restful sleep

Many people with CSA also have heart disease, especially heart failure.⁵ Within this population, individuals who have CSA are at increased risk for hospitalizations and even death.^7,8

What causes central sleep apnea?

Central sleep apnea may be caused by a number of factors, including²:

• Cardiac disorders, including congestive heart failure (CHF) and atrial fibrillation (AFib)
• High altitude
• Opioids
• Positive Airway Pressure (PAP) therapy
• Idiopathic central sleep apnea
• Other medical conditions

Cardiac disorders

Heart failure is the most common cause of central sleep apnea. Research indicates that up to 40% of congestive heart failure (CHF) patients and 30% of atrial fibrillation (AFib) patients may have CSA.^2,9,10

High altitude

Sleep apnea may occur when exposed to high altitudes, as a result of how the body responds to changes in atmospheric pressure.²

Opioids

Certain medications, including opioids, can disrupt breathing and lead to CSA.²

Positive Airway Pressure (PAP) therapy

In some cases, PAP therapy (such as CPAP or BiPAP) can cause CSA to occur. This is known as treatment-emergent CSA. Treatment-emergent CSA can be caused by an increased number of arousals during titration, mask leak, or over-titration. It may improve with ongoing PAP use.²

Idiopathic central sleep apnea

Although rare, there are some cases in which the cause of CSA cannot be identified.² This is known as idiopathic CSA.

Other medical disorders

A number of other medical disorders, such as stroke or severe kidney disease, have also been associated with CSA.

Treatment Options

The remedē System

remedē is the only FDA-approved non-mask therapy designed to treat moderate to severe CSA in adults. It’s a small, implantable device that turns on automatically each night, stimulating the phrenic nerve to restore a more normal breathing pattern during sleep. As with any implantable device procedure, there is a risk of implant site infection.¹¹

Positive Airway Pressure (PAP) therapy

PAP devices are often used to treat central sleep apnea. Various types exist, including those that provide continuous pressure (i.e., CPAP) and those that provide variable pressure (e.g., BiPAP, ASV). ASV, or adaptive-servo ventilation, should not be used in patients with chronic, symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 45%).¹⁰

Supplemental oxygen

Doctors may recommend the use of supplemental oxygen for patients with central sleep apnea. The oxygen may be delivered through a mask, tube, or tent.¹²

Medications

Prescription medications, including acetazolamide and theophylline, have been attempted as therapies for CSA. There is limited data on their efficacy and safety.

Why treat central sleep apnea?

Deep, restorative sleep is critical for mental wellbeing and long-term physical health. With proper diagnosis and effective treatment, it’s possible to manage central sleep apnea symptoms—improving sleep and quality of life.

What should I do if I think I have CSA?

Only a sleep specialist can accurately diagnose sleep apnea. If you or a loved one is experiencing signs and symptoms of CSA, be sure consult your doctor.

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4. Morgenthaler T; Gay P; Gordon N et al. Adaptive servoventilation versus noninvasive positive pressure ventilation for central, mixed, and complex sleep apnea syndromes. SLEEP 2007;30(4):468-475.
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