Pathophysiology of upper airway obstruction during sleep.

The obstructive sleep apnoea syndrome (OSAS) is characterised by repetitive upper airway obstructions leading to snoring, hypopnoeas and apnoeas. Sleep fragmentation and arterial oxygen desaturations are the first consequences. Since the discovery of the OSAS, an impressive series of studies were done on upper airway physiology, and more specifically, on the pharyngeal airway. The objective of this article is to review the pathophysiological basis of upper airway obstruction during sleep.