Asthma and Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea syndrome (OSAS) results from obstruction of the upper airway with resultant brief periods of breathing cessation of at least 10 seconds (apnea) or marked reductions in flow (hypopnea) during sleep that are insufficient to meet the definition of apnea. This pattern is accompanied by oxyhemoglobin desaturation, persistent inspiratory efforts against the occluded airway, and arousal from sleep. Clinically, the condition is recognized by recurrent sleep interruptions, snoring, choking and gasping spells on awakening, and daytime drowsiness caused by loss of normal sleep. The diagnosis is confirmed and graded on overnight polysomnography criteria. If uncorrected, the disorder often can lead to hypertension, respiratory failure, and cardiac abnormalities. Data suggest that OSAS is an independent risk factor for asthma exacerbations and that OSAS symptoms are more common in asthmatic patients than in the general population, hence linking these two major diseases. Both conditions share mechanical, hormonal, and immunologic reasons for their effects. However, studies show that continuous positive airway pressure might modify airway smooth muscle function and asthma control in patients with both disorders.