Upper airway collapsibility in habitual snorers and sleep apneics: evaluation with drug-induced sleep endoscopy

Increased upper airway collapsibility has been suspected of being involved in the pathogenesis of sleep-related diseases. It is assumed that patients with severe obstructive sleep apnea syndrome (OSAS) show a stronger collapse of the upper airway compared with habitual snorers. It was the objective of this study to analyze the patterns of upper airway collapse in habitual snorers and patients with OSAS and to correlate these results with data from polysomnography. Endoscopy was carried out during drug-induced sleep (with propofol) and collapsibility was analyzed at two major levels (palatal and tongue base). A total of 207 habitual snorers and 117 patients with OSAS underwent endoscopy after overnight polysomnography in our sleep laboratory. In 95% of cases we were able to induce snoring during drug-induced sleep. The collapsibility in the area of the base of the tongue correlated with higher values of the respiratory disturbance index (RDI) as recorded by standard polysomnography. Patients with OSAS showed significantly stronger collapsibility compared with snorers. The difference was more evident at the tongue-base level. We found no significant correlation between the applied CPAP pressure and collapsibility in patients with OSAS. These results show that collapsibility at the tongue-base level is a factor relevant in sleep-related breathing disorders.