Pharyngeal cross-sectional area and pharyngeal compliance in normal Japanese males and females

Abstract

It is reported that obstructive sleep apnea syndrome (OSAS) has a marked elderly male predominance and that patients with OSAS have reduced pharyngeal cross-sectional area and increased pharyngeal collapsibility. These reports suggest that the size and mechanical properties of the pharynx have sex- and age-related differences even in normal subjects. However, there are only a few reports on normal values of pharyngeal cross-sectional area and compliance. The purpose of this study was to determine the normal values of the pharyngeal cross-sectional area and compliance in Japanese healthy subjects and to determine sex-related differences and the effect of age, body size, and body posture on these parameters. We examined 181 subjects with an age range spanning 21-69 years, with normal range of body mass index and without enlarged tonsils or jaw retrusion. No subject complained of symptoms suggestive of OSAS. We measured the pharyngeal cross-sectional area in three body positions (sitting, lateral and supine) using the acoustic reflection technique (AAAR). Fifty airway area versus distance functions with a rate of 3 times per second were measured and averaged in each body position during normal breathing of room air. After identifying the fauces and the glottis on the averaged area versus distance function, we defined a region between 2 cm distal to the fauces and 2 cm proximal to the glottis as a pharyngeal segment and computed the mean area of that segment (mean pharyngeal cross-sectional area).(ABSTRACT TRUNCATED AT 250 WORDS)