An apneic episode is a temporary, involuntary cessation of breathing or a significant reduction in airflow, typically lasting ten seconds or more. This event commonly occurs during sleep, preventing the body from taking in sufficient oxygen and forcing the brain to partially wake the person to resume breathing. The condition is widely prevalent, affecting hundreds of millions of people globally, and often goes undiagnosed.
Categorizing Apneic Episodes
Apneic episodes are categorized based on the underlying physiological mechanism causing the pause in breathing. Understanding these distinctions is important because the cause determines the appropriate treatment pathway.
The most common form is Obstructive Sleep Apnea (OSA), which occurs when the upper airway physically narrows or collapses during sleep. The soft tissues at the back of the throat relax, blocking the passage of air despite the chest and diaphragm still attempting to breathe.
In contrast, Central Sleep Apnea (CSA) arises from a failure in communication between the brain and the respiratory muscles. The brain does not send the necessary signals to initiate a breath, resulting in an absence of both airflow and respiratory effort. CSA is less common than OSA and is often linked to underlying medical conditions like heart failure or neurological disorders.
A third classification, Mixed Apnea, involves a combination of both central and obstructive mechanisms within the same episode. These episodes may begin with a central component where the breathing signal stops, followed by an obstructive element as the airway collapses.
Apnea of Prematurity (AOP) is a separate condition affecting newborns, defined as a pause in breathing lasting 20 seconds or more, or a shorter pause accompanied by a low heart rate or oxygen saturation. AOP results from the developmental immaturity of the central nervous system, where the brain’s respiratory control centers are not fully developed. This condition is mostly seen in infants born before 37 weeks gestation, with the incidence increasing significantly with lower gestational age.
Recognizing the Warning Signs
Identifying apneic episodes relies on recognizing signs that manifest both during sleep and throughout the day. At night, the most noticeable sign is loud, habitual snoring, though not everyone who snores has apnea. A sleeping partner frequently observes breathing irregularities, such as gasping, choking sounds, or noticeable pauses in breath followed by a sudden snort. These events disrupt sleep, leading to a restless night marked by frequent arousals or waking up feeling short of breath.
The consequence of this fragmented sleep often presents as excessive daytime sleepiness (EDS) or chronic fatigue. EDS can impair daily functioning, affecting concentration, memory, and reaction time. Other daytime indicators include waking up with a morning headache, which may be related to decreased oxygen levels overnight, or experiencing a dry mouth or sore throat. These observable signs are not definitive proof of apnea but should prompt consultation with a healthcare provider for further evaluation.
The Diagnostic Process and Monitoring
A specialized sleep study is necessary to confirm the diagnosis and determine the severity of apneic episodes. The standard evaluation is Polysomnography (PSG), an overnight test conducted in a laboratory setting. PSG monitors several physiological parameters, including brain activity, eye movement, heart rate, oxygen saturation, and respiratory effort.
Portable home sleep apnea tests (HSATs) offer a more convenient alternative, though they measure fewer parameters than PSG. These tests are generally used to diagnose Obstructive Sleep Apnea in people with a high probability of the condition.
Regardless of the testing method, results are quantified using the Apnea-Hypopnea Index (AHI). The AHI calculates the average number of apneas and hypopneas—partial breathing reductions—that occur per hour of sleep.
The AHI score classifies the severity of the condition:
- An AHI of fewer than five events per hour is considered normal.
- A score between five and fifteen indicates mild apnea.
- Moderate apnea falls within the range of fifteen to thirty events per hour.
- A score exceeding thirty events per hour is classified as severe.
This objective measurement guides treatment decisions and monitors therapy effectiveness.
Current Treatment Approaches
Treatment for apneic episodes is tailored to the specific type and severity of the condition, aiming to restore normal breathing and improve sleep quality.
Obstructive Sleep Apnea (OSA) Treatment
For moderate to severe Obstructive Sleep Apnea, Continuous Positive Airway Pressure (CPAP) therapy is the most common and effective treatment. A CPAP machine delivers pressurized air through a mask worn during sleep, creating an air splint that prevents the upper airway from collapsing.
For those with mild or moderate OSA who cannot tolerate CPAP, alternative options exist. Oral appliance therapy involves custom-fitted dental devices that reposition the jaw or tongue to keep the airway open. Lifestyle adjustments, such as weight loss, avoiding alcohol before bed, and positional therapy to encourage side sleeping, can also reduce the number of events.
Surgical interventions may be considered in specific cases, such as the removal of enlarged tonsils or procedures to modify the soft palate tissue. Advanced therapies like upper airway stimulation involve implanting a small device that electrically stimulates the nerves controlling the tongue muscles to maintain airway patency.
Central Sleep Apnea (CSA) Treatment
Treatment for Central Sleep Apnea focuses on managing the underlying medical condition. Specialized devices like Adaptive Servo-Ventilation (ASV) or supplemental oxygen may also be prescribed.