Sleep Apnea 101

Overview of Complex Sleep Apnea

Complex sleep apnea is a multifaceted and often misunderstood condition that combines elements of both obstructive sleep apnea (OSA) and central sleep apnea (CSA). It poses unique challenges in diagnosis and treatment, making it essential for healthcare providers and patients to understand its complexities. This article provides a comprehensive overview of complex sleep apnea, exploring its definition, causes, symptoms, diagnosis, and treatment options.

Understanding Sleep Apnea

Man sleeping with his mouth open

To grasp complex sleep apnea, it’s crucial to first understand the two primary types of sleep apnea:

Obstructive Sleep Apnea (OSA)

OSA is the most common form of sleep apnea. It occurs when the muscles at the back of the throat fail to keep the airway open, despite efforts to breathe. This obstruction can cause repetitive pauses in breathing during sleep, leading to fragmented sleep and decreased oxygen levels.

Central Sleep Apnea (CSA)

CSA, on the other hand, is less common and occurs when the brain fails to send proper signals to the muscles that control breathing. Unlike OSA, there is no physical blockage in the airway. Instead, the issue lies in the communication between the brain and the respiratory system.

What Is Complex Sleep Apnea?

Complex sleep apnea, also known as treatment-emergent central sleep apnea, is characterized by the presence of both OSA and CSA. Initially, a person may be diagnosed with OSA and begin treatment with continuous positive airway pressure (CPAP) therapy. However, during treatment, central apneas may emerge, complicating the clinical picture.

Causes of Complex Sleep Apnea

Cpap machine

The exact causes of complex sleep apnea are not entirely understood, but several factors may contribute to its development:

CPAP Therapy

CPAP therapy is a common treatment for OSA. It works by delivering a steady stream of air through a mask to keep the airway open. However, in some patients, this therapy can lead to the emergence of central apneas, transforming the condition into complex sleep apnea.

Underlying Medical Conditions

Certain medical conditions can predispose individuals to complex sleep apnea. These include heart failure, atrial fibrillation, stroke, and other neurological disorders. These conditions can affect the brain’s ability to regulate breathing.

Opioid Use

Chronic use of opioids can depress the respiratory system and contribute to the development of central sleep apnea. When combined with OSA, this can lead to complex sleep apnea.

High Altitude

Sleeping at high altitudes can induce central sleep apnea due to changes in oxygen levels and respiratory patterns. For individuals with OSA, this can exacerbate their condition and lead to complex sleep apnea.

Symptoms of Complex Sleep Apnea

Loud Snoring

The symptoms of complex sleep apnea are similar to those of OSA and CSA but can be more challenging to manage. Common symptoms include:

Daytime Fatigue

Persistent daytime fatigue is a hallmark symptom of sleep apnea. Despite spending adequate time in bed, individuals with complex sleep apnea often wake up feeling unrefreshed.

Loud Snoring

Loud and chronic snoring is typical in OSA and can also be present in complex sleep apnea. This snoring may be accompanied by choking or gasping sounds.

Pauses in Breathing

Observed pauses in breathing during sleep, followed by abrupt awakenings, are common in both OSA and CSA.


Difficulty staying asleep or frequent awakenings during the night can occur due to disruptions in breathing.

Cognitive Impairment

Complex sleep apnea can lead to difficulties with concentration, memory, and overall cognitive function.

Morning Headaches

Waking up with headaches is another common symptom, often due to decreased oxygen levels during sleep.

Diagnosis of Complex Sleep Apnea

Diagnosing complex sleep apnea involves a thorough evaluation by a sleep specialist. The diagnostic process typically includes:


Polysomnography, or a sleep study, is the gold standard for diagnosing sleep apnea. This overnight test monitors various physiological parameters, including brain activity, eye movements, muscle activity, heart rate, and respiratory effort. It helps identify the presence of obstructive and central apneas.

Continuous Positive Airway Pressure (CPAP) Titration

For individuals initially diagnosed with OSA, CPAP titration studies help determine the appropriate pressure settings for CPAP therapy. If central apneas emerge during this process, complex sleep apnea may be diagnosed.

Medical History and Physical Examination

A comprehensive medical history and physical examination are essential to identify potential underlying conditions contributing to complex sleep apnea.

Treatment Options for Complex Sleep Apnea

ProSomnus® Sleep and Snore Device

Managing complex sleep apnea requires a multifaceted approach tailored to the individual’s specific needs. Treatment options may include:

Oral Appliance

An oral appliance is a small, unobtrusive appliance that is similar to a retainer or a mouthguard. It sits in the mouth during the night and prevents the tongue from falling back into the mouth. This can help relieve symptoms of the obstructive sleep apnea symptoms of CSA when combined with another treatment that focuses on the symptoms of central sleep apnea.

Adaptive Servo-Ventilation (ASV)

ASV is a specialized form of positive airway pressure therapy designed to treat both obstructive and central apneas. It adjusts the pressure dynamically based on the patient’s breathing patterns, providing support during central apneas and ensuring the airway remains open during obstructive events.

Bi-level Positive Airway Pressure (BiPAP)

BiPAP therapy delivers two levels of pressure: higher during inhalation and lower during exhalation. This mode can be beneficial for patients who have difficulty tolerating CPAP or who have significant central apneas.

Medication Management

For individuals with underlying medical conditions contributing to complex sleep apnea, appropriate management of these conditions is crucial. This may include medications for heart failure, neurological disorders, or other relevant health issues.

Lifestyle Modifications

Lifestyle changes can play a significant role in managing complex sleep apnea. These may include weight loss, avoiding alcohol and sedatives, quitting smoking, and maintaining a regular sleep schedule.

Oxygen Therapy

In some cases, supplemental oxygen therapy may be prescribed to ensure adequate oxygen levels during sleep, particularly for individuals living at high altitudes or those with severe oxygen desaturation.


Surgical interventions may be considered in cases where anatomical abnormalities contribute to obstructive sleep apnea. Procedures such as uvulopalatopharyngoplasty (UPPP) or maxillomandibular advancement (MMA) can help reduce airway obstruction.


Complex sleep apnea is a challenging condition that requires careful diagnosis and a tailored treatment approach. Understanding its causes, symptoms, and treatment options is essential for effectively managing this multifaceted disorder. Through a combination of advanced therapies, lifestyle modifications, and medical management, individuals with complex sleep apnea can achieve improved sleep quality and overall health. As research continues to advance, the hope is that more effective treatments and management strategies will emerge, providing relief and better outcomes for those affected by this complex condition.

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