Objective: To study the nasal resistance in different position and its possible relationship to obstructive sleep apnea syndrome (OSAS).
Method: The positional rhinomanometry and the detection of polysomnography were performed in 14 normal subjects, 20 snoring patients and 40 patients with OSAS.
Result: The study reveals that: 1. the nasal resistance in seated position and in supine position of the patients with OSAS but without nasal diseases or snoring patients without nasal disease were higher than that of the normal group (P < 0.05). 2. The nasal resistance in seated position and in supine position of the patients with both OSAS and nasal disease were higher than that of the snoring patients with nasal disease (P < 0.05). 3. The nasal resistance in supine position was higher than the nasal resistance in seated position in all the groups (P < 0.05), even in the patients with OSAS (P < 0.01). 4. The AHI, waken intervals, snoring index of the patients both with OSAS and nasal disease were higher than those of the patients only with OSAS.
Conclusion: Nasal resistance increased in the patients with snoring or OSAS and increased more in the supine position. Nasal resistance may be an important factor in the pathogenesis of OSAS.