2. Evidence by polysomnography 0t 15 or more obstructive apneas andlor hypopneas per hour of sleep regardless of accompanying symptoms.
Specify current severity:
Mild: Apnea hypopnea index is less than 15.
Moderate: Apnea hypopnea index is 15-30.
Severe: Apnea hypopnea index is greater than 30.
Disease severity is measured by a count of the number of apneas plus hypopneas per hour of sleep (apnea hypopnea index) using polysomnography or other overnight monitoring.
Overall severity is also informed by levels of nocturnal desaturation and sleep fragmen- tation (measured by brain cortical arousal frequency and sleep stages) and degree of as- sociated symptoms and daytime impairment. However, the exact number and thresholds may vary according to the specific measurement techniques used, and these numbers may change over time. Regardless of the apnea hypopnea index (count) per se, the disorder is considered to be more severe when apneas and hypopneas are accompanied by significant oxygen hemoglobin desaturation (e.g., when more than 10% of the sleep time is spent at desaturation levels of less than 90%) or when sleep is severely fragmented as shown by an elevated arousal index (arousal index greater than 30) or reduced stages in deep sleep (e.g., percentage stage N3 [slow-wave sleep] less than 5%).
Obstructive sleep apnea hypopnea is the most common breathing-related sleep disorder.
It is characterized by repeated episodes of upper (pharyngeal) airway obstruction (apneas and hypopneas) during sleep. Apnea refers to the total absence of airﬂow, and hypopnea re- fers to a reduction in airﬂow. Each apnea or hypopnea represents a reduction in breathing of at least 10 seconds in duration in adults or two missed breaths in children and is typi- cally associated with drops in oxygen saturation of 3% or greater and / or an electroenceph— alographic arousal. Both sleep-related (nocturnal) and wake-time symptoms are common.
The cardinal symptoms of obstructive sleep apnea hypopnea are snoring and daytime sleepiness.
Obstructive sleep apnea hypopnea in adults is diagnosed on the basis of polysom- nographic findings and symptoms. The diagnosis is based on symptoms of 1) nocturnal breathing disturbances (i.e., snoring, snorting/gasping, breathing pauses during sleep), or 2) daytime sleepiness, fatigue, or unrefreshing sleep despite sufficient opportunities to sleep that are not better explained by another mental disorder and not attributable to an- other medical condition, along with 3) evidence by polysomnography of five or more ob- structive apneas or hypopneas per hour of sleep (Criterion A1). Diagnosis can be made in the absence of these symptoms if there is evidence by polysomnography of 15 or more ob- structive apneas and / or hypopneas per hour of sleep (Criterion A2).
Specific attention to disturbed sleep occurring in association with snoring or breathing pauses and physical findings that increase risk of obstructive sleep apnea hypopnea (e.g., central obesity, crowded pharyngeal airway, elevated blood pressure) is needed to reduce the chance of misdiagnosing this treatable condition.
Because of the frequency of nocturnal awakenings that occur with obstructive sleep apnea hypopnea, individuals may report symptoms of insomnia. Other common, though non— specific, symptoms of obstructive sleep apnea hypopnea are heartburn, nocturia, morning headaches, dry mouth, erectile dysfunction, and reduced libido. Rarely, individuals may complain of difficulty breathing while lying supine or sleeping. Hypertension may occur in more than 60% of individuals with obstructive sleep apnea hypopnea.