[Respiratory disorders during sleep]

Abstract

Sleep-disordered breathing includes snoring, upper airway resistance syndrome, sleep hypopneas and apneas, and is a borderline pathology between several disciplines (neurology, pneumology, cardiology, oto-rhino-laryngology, etc.). The common element is an abnormal increase in upper airway resistance during sleep. In mild cases, this increase accelerates airflow and induces vibrations of the pharyngeal structures (snoring); in severe cases the airway is occluded and airflow ceases (obstructive apnea). Sleep apnea syndrome (SAS) is present in 4% of males and 2% females in the general population. The risk factors are an age above 50, male sex, weight excess, presence of respiratory symptoms, tobacco smoking, alcohol consumption, use of hypnotic drugs... Snoring is much more frequent than sleep apnea, present in up to 50% of males aged 50 yr or more; most snorers do not have apneas ("simple" snorers). Apneas end with a micro-arousal; this sleep disruption explains the excess daytime sleepiness of patients with SAS. The daytime sleepiness is responsible for the increased rate of accidents (traffic, domestic, work...) in SAS patients. The second effect of apneas is desaturation, leading to heart rhythm abnormalities, coronary or cerebrovascular accidents, pulmonary vasoconstriction, systemic hypertension, etc. Screening for SAS is justified by its prevalence, by the potentially severe consequences and by the existence of an efficacious treatment: continuous positive airway pressure.