Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing. It is due to a partial or complete collapse of the upper airway that causes muscles controlling the soft palate and tongue to relax. A person experiences apneas (cessation of airflow for more than 10sec), hypopneas (a decrease of airflow for more than 10sec with a 30% oxygen reduction in airflow and with at least a 4% oxygen desaturation from baseline) and flow limitation during sleep (narrowing of the upper airway and an indication of an impending upper airway closure). OSA is classified based on the number of apneas and/or hypopneas per hour of sleep with less than 4 as normal and more than 30 as severe. Signs and symptoms of OSA are lack of energy, hypertension, frequent nocturnal urination, obesity, excessive daytime sleepiness (EDS), gastroesophageal reflux, morning headaches, diabetes, depression, large neck size, nighttime gasping/choking/coughing, and irregular breathing during sleep (ie. Snoring).
Thers is about 42 million American adults have SDB. About 1 in 5 adults has mild OSA and 1 in 15 has mod to severe OSA. About 9% of middle-aged women, 25% of men in middle-aged work force suffer from OSA. About 75% of severe SDB cases remain undiagnosed.
The increased risk factors for OSA are male gender, obesity with BMI greater than 30, diagnosis of hypertension, family history of OSA, upper airway or facial abnormalities, large neck circumference (>17” in men and >16” in women), excessive use of alcohol or sedatives, smoking, endocrine and metabolic disorders, and increasing age.
The comorbid associatios with OSA are hypertension, cardiovascular diseases (arrhythmias, myocardial infarctions, heart failures), stroke, diabetes type 2, mood disorders (anxiety and /or depression), increased morbidity and mortaligy, and obesity. OSA increased health care cost and traffic accidents.
Treatment of OSA with CPAP resulted in a 10mmHg reduction in blood pressure which would reduce stroke risk by 35% and coronary heart disease by 20%. CPAP also reduces blood glucose levels by improve insulin sensitivity. CPAP improved the prognosis of heart failure patients with OSA.
