Sleep Disordered Breathing

sleep apnea circle
Sleep Disordered Breathing (SDB) is a spectrum of disorders related to breathing abnormalities during sleep. SDB is the greatest percentage of overall sleep disorders seen by physicians and represents significant morbidity.

SDB includes several disorders related to a compromised airway including:

Upper Airway Resistance Syndrome (UARS)
Obstructive Sleep Apnea (OSA)

Though snoring may seem like an annoyance at best, it can actually be the first manifestation of SDB that, left untreated, will lead to OSA. This occurs through a vicious cycle where snoring causes inflammation, leading to a more compromised airway and lower oxygen availability, causing more snoring and more inflammation.


Snoring is the most common symptom of SDB. The International Classification of Sleep Disorders Diagnostic and Coding Manual defines snoring as, “a respiratory sound generated in the upper airway during sleep that typically occurs during inspiration but may also occur in expiration, without episodes of apnea or hypoventilation.” Per the above definition, simple snoring is not accompanied by periods of time where the person stops breathing and oxygen levels drop. As mentioned, however, snoring can lead to OSA. Patients treated with an oral appliance have their snoring eliminated, thus decreasing inflammation and the likelihood of progression to more severe SDB.


UARS has symptoms similar to OSA, but with the important distinction that oxygen concentration in the blood does not decrease and no apneic events occur. Instead, resistance to airflow is significant enough to cause short episodes of arousal from sleep. These episodes are referred to as respiratory effort-related arousals (RERAs). The patient is usually not aware of the “mini awakenings” but they breakup the normal sleep pattern leading to excessive daytime sleepiness.


OSA, also known as Obstructive Sleep Apnea-Hyponea Syndrome (OSAHS), is similar to UARS in that partial or complete airway obstruction leads to awakenings or arousals in order to re-establish normal breathing. However, unlike UARS, during OSA partial (hypopnea) or complete (apnea) cessation of airflow occurs leading to decreased oxygen concentration in the blood. OSA is a very prevalent disorder that is severely under-diagnosed. And diagnosis is urgent since with OSA leads to an increased risk of high blood pressure, heart disease, diabetes, and stroke.