What is an Obstructive Sleep Apnea (OSA)?

In Greek “apnea” translates to “without breath” and is characterized by repetitive episodes of blocked or restricted breaths sometimes hundreds of times during a single night and affects millions of Americans. There are three types of sleep apnea: Obstructive, central, and mixed. Obstructive sleep apnea (OSA) is caused by changes in the position of the tongue during sleep that result in the closure of the soft tissues at the rear of the throat.

Central sleep apnea is caused by the failure of the brain to send breathing control signals to the muscles responsible for breathing. Mixed sleep apnea is a combination of both obstructive and central, and Obstructive Sleep Apnea is the most prevalent of the three. OSA is characterized by the complete obstruction of airway causing breathing to cease completely (Apnea) or partially (Hypopnea) for intervals ranging from seconds to minutes. The human airway (at the level of the thorax) is lined by soft tissue, any collapse of its walls results in the closure of the airway which leads to insufficient oxygen intake, thereby interrupting one’s sleep (episodes or micro-arousals). Obstructive sleep apnea is a potentially life-threatening disease that often goes undiagnosed in most patients affected by sleep apnea.

The severity of sleep apnea is determined by dividing the number of episodes of apneas and hypopneas lasting ten seconds or more by the number of hours of sleep. The resulting number is called the Apnea-Hypopnea Index, or AHI.

AHI #	Condition
Below 5	No OSA
5-15	Mild OSA
15-30	Moderate OSA
Over 30	Severe OSA