Central sleep apnea (CSA) is a sleep disorder where a person repeatedly stops breathing during sleep. This occurs because the brain does not send the necessary signals to the breathing muscles. Unlike obstructive sleep apnea (OSA), which involves a physical airway blockage, CSA stems from a neurological issue. Though less common than OSA, CSA is a distinct condition with potential health implications.
Understanding Central Sleep Apnea
Central sleep apnea stems from a neurological issue where the brain’s respiratory control centers fail to properly signal the breathing muscles. This results in no effort to breathe for a period, typically 10 to 30 seconds, leading to a temporary cessation or reduction in airflow. This lack of respiratory effort differentiates CSA from obstructive sleep apnea, where the individual tries to breathe against a blocked airway.
The breathing pattern in CSA can be irregular, sometimes characterized by alternating periods of no breathing with periods of deep, rapid breathing, known as Cheyne-Stokes breathing. This pattern is often associated with certain underlying medical conditions, such as congestive heart failure or stroke. Other potential causes or associated conditions include high-altitude sleeping, the use of certain medications like opioids, and, in some cases, no clear cause is identified.
Health Implications of Untreated Central Sleep Apnea
Untreated central sleep apnea can lead to various health complications due to repeated drops in blood oxygen levels and fragmented sleep. These issues can affect multiple body systems, underscoring the importance of proper management.
Cardiovascular issues are a significant concern with untreated CSA. The sudden drops in blood oxygen and the body’s response to restart breathing can strain the heart and blood vessels. This can contribute to or worsen conditions such as high blood pressure, heart failure, and irregular heart rhythms like atrial fibrillation. Individuals with existing heart disease may face an increased risk of heart attack or stroke.
Untreated CSA can also have neurological effects. The lack of restorative sleep often results in severe fatigue, excessive daytime sleepiness, and irritability. Individuals may experience difficulty concentrating, memory problems, and a reduced ability to focus. This chronic sleep deprivation can also increase the risk of accidents.
There are also potential links to kidney and metabolic issues. Some medical conditions, including end-stage kidney disease, can be associated with central sleep apnea. Sleep apnea, in general, has been linked to insulin resistance and a higher risk of developing type 2 diabetes, suggesting a potential metabolic impact.
Identifying Central Sleep Apnea
Recognizing central sleep apnea often begins with observing certain symptoms. Common signs include pauses in breathing during sleep, sudden awakenings accompanied by shortness of breath, and difficulty staying asleep. Daytime symptoms can also be indicative, such as excessive sleepiness, morning headaches, and trouble concentrating. Snoring can occur, but it may not be as prominent as in obstructive sleep apnea.
A definitive diagnosis requires a comprehensive sleep study, known as polysomnography. This overnight test is typically conducted in a specialized sleep laboratory or, in some cases, at home. During the study, various bodily functions are monitored:
Brain waves
Heart rate
Breathing patterns
Oxygen levels in the blood
Muscle activity
This monitoring helps differentiate CSA from other sleep disorders and identifies the severity of breathing disruptions.
Managing Central Sleep Apnea
Managing central sleep apnea often involves a multi-faceted approach, primarily addressing any underlying conditions. For instance, if heart failure is a factor, optimizing its treatment can significantly improve CSA symptoms. If opioid use is identified as a cause, a healthcare team may gradually reduce the dosage of these medications.
Adaptive Servo-Ventilation (ASV) is a common and effective therapy for central sleep apnea. This device monitors breathing patterns and adjusts the air pressure delivered through a mask to stabilize breathing throughout the night. Unlike continuous positive airway pressure (CPAP), which delivers a constant pressure, ASV dynamically changes the pressure to support breathing when needed. While effective, ASV may not be recommended for all individuals, particularly those with a certain type of heart failure with reduced ejection fraction.
Supplemental oxygen may also be used to maintain adequate blood oxygen levels during sleep. This therapy is particularly helpful for individuals who experience low oxygen saturation. Medications such as acetazolamide have been explored to stimulate breathing, especially if positive airway pressure devices are not well tolerated. An implantable device that stimulates the phrenic nerve to control the diaphragm has also been approved for certain types of CSA, providing another treatment option.