[Pharyngeal size and collapsibility in patients with obstructive sleep apnea hypopnea syndrome]

Abstract

Objective: To study the pharyngeal cross-sectional area and collapsibility among the patients with obstructive sleep apnea hypopnea syndrome (OSAHS), simple snorers, and normal persons.

Methods: 171 patients with OSAHS, 44 with mild, 51 with moderate, and 56 with severe OSAHS, 47 simple snorers, and 47 healthy subjects underwent upper airway cross-sectional area measurement using acoustic pharyngometer at the conditions of functional residual capacity (FRC) and residual volume (RV) in the upright sitting position.

Results: When the lung volume decreased from the condition of FRC to the condition of RV the pharyngeal cross-sectional area decreased from 2.63 cm(2) +/- 0.42 cm(2) to 1.96 cm(2) +/- 0.35 cm(2) for the simple snorers, 2.70 cm(2) +/- 0.44 cm(2) to 1.78 cm(2) +/- 0.39 cm(2) for the mild OSAHS patients, from 2.62 cm(2) +/- 0.52 cm(2) to 1.79 cm(2) +/- 0.37 cm(2) for the moderate OSAHS patients, and from 2.57 cm(2) +/- 0.46 cm(2) to 1.75 cm(2) +/- 0.40 cm(2) for the severe OSAHS patients, all with higher decrease rates (33.93% +/- 11.81%, 31.13% +/- 10.76%, and 31.31% +/- 13.44%) than that of the normal persons (25.07% +/- 10.39%), smaller than that for the normal persons (21.11% +/- 8.19%, from 3.05 cm(2) +/- 0.6 cm(2) to 2.38 cm(2) +/- 0. 47 cm(2), all P < 0.05). The change ratios of the 3 OSAHS groups were significantly higher than that of the simple snorer group (all P < 0.01). This indicated that the pharynges of OSAHS patients were more collapsible.

Conclusion: Snorers with or without apnea have smaller pharyngeal cross-sectional area than nonsnorers. The collapsibility of the upper airway is greater in both OSHAS patients and simple snorers than in healthy subjects.