Q. What is sleep apnea? A. Derived from the Greek word for “lack of breath,” sleep apnea is a serious, potentially life-threatening sleep-related breathing disorder that is often linked with loud, heavy snorers. Sleep apnea can be the result of an abnormality in the respiratory pacemaker in the brain (central sleep apnea) or, more commonly, it may be triggered by an obstruction in the upper airway (obstructive sleep apnea), which decreases the amount of inhaled air, collapsing the tissue in the back of the throat, and disrupting sleep. An episode of partial airway closing is called a sleep hypopnea. Patients with OSA experience repetitive episodes of obstruction of the upper airway during sleep, lasting anywhere from 30 seconds up to two minutes. With no air flowing into the lungs, oxygen levels drop and carbon dioxide levels rise in the blood. The reduction in oxygen and increased carbon dioxide alert the brain to resume breathing and cause an arousal. Finally, the patient awakens with a jolt and resumes breathing, and quickly falls back to sleep—and resumes the loud snoring. Blood pressure spikes up during the arousal, sometimes by as much as 30 mm Hg systolic, the top number in your hypertension reading. As the person goes back to sleep, typically unaware of having awakened, the throat muscles relax once again, the airway closes, and the sleep apnea pattern is repeated again. And again. And again. These subsequent and frequent arousals, although necessary for breathing to restart, prevent the patient from getting enough restorative, deep sleep. There are two major types of sleep apnea. The most common is obstructive sleep apnea, or OSA, which affects upwards of 45 million Americans. Central sleep apnea (CSA), which is less common, is caused by a failure of the brain to signal the muscles to breathe. |
