[Obstructive sleep apnea syndrome].

The obstructive sleep apnea syndrome (OSAS) is caused by an intermittent and repetitive obstruction of the upper respiratory tract during sleep, which leads to a complete (apnea) or partial (hypopnea) block of air flow. It is quite prevalent, being seen in 4-6% of males and 2% of females. Structural abnormalities present in the upper respiratory tract and obesity are the fundamental etiological factors. Clinical manifestations are due to sleep fragmentation and oxygen desaturation which cause the apnea. Day hypersomnia, snoring and episodes of apnea described by the spouse are the three basic symptoms. The diagnosis is based on polysomnography, which can be substituted for a night cardiorespiratory polygraphy. It has an important morbimortality rate, mainly due to traffic and labor accidents, ischemic heart disease and chronic respiratory failure. The treatment is multifactorial. First, eliminating alcohol and hypnotic drugs. Obesity, which is almost always present, must also be corrected. Structural abnormalities of the upper respiratory tract may require a surgical solution. The treatment preferred nowadays is the application of a nasal continuous positive airway pressure (CPAP) while the patient is asleep. It should be considered for those symptomatic patients with an apnea-hypopnea index over 30, or if the index is below 30, than when a respiratory insufficiency or cardiovascular risk factors are present. In some cases surgical procedures may be considered, such as uvulopalatopharyngoplasty.