[Patterns of bilateral nasal airflow distribution and influencing factors in patients with obstructive sleep apnea]

Objective: To investigate the characteristics of the nasal cycle and the patterns of bilateral nasal airflow distribution in patients with obstructive sleep apnea (OSA). Methods: This cross-sectional study analyzed data from 29 healthy subjects (control group: 16 males, 13 females; age range 23-60 years, mean 31.03±8.67 years) and 41 patients with OSA (OSA group: 34 males, 7 females; age range 20-62 years, mean 39.73±11.27 years) who visited the Sleep Medicine Center of Beijing Tongren Hospital, Capital Medical University, between March 2022 and April 2025. Whole-night split-channel nasal airflow and polysomnography were performed to calculate nasal airflow laterality, nasal cycle duration, and the effects of severity, sleep stages, and body position on bilateral nasal airflow distribution during sleep were analyzed. Results: The nasal cycle duration in OSA patients was significantly shorter than in controls (179.5 min vs. 312.5 min, χ²=14.01, P<0.001). Apnea-hypopnea index (AHI) and age were independent influencing factors. In the OSA group, the incidence of nasal cycle transitions within 10 minutes after wake [(observed)7/50 vs. 2/55(expected), χ²=14.32, P<0.001], REM sleep [(observed)23/34 vs. 14/43(expected), χ²=8.14, P=0.004], and position changes (21/36 vs. 11/46, χ²=12.02, P<0.001) was higher, while, in the control group, it was only associated with REM sleep (15/15 vs. 8/22, χ²=8.80, P=0.003). Nasal airflow lateralization in the OSA group showed a stronger correlation with body position. The nasal airflow lateralization in the supine position was significantly lower in OSA patients than in controls [REM stage: 0.626 (0.425, 0.743) vs. 0.781 (0.706, 0.857), Z=3.62, P<0.001; N3 stage: 0.526 (0.438, 0.600) vs. 0.716 (0.608, 0.853), Z=2.17, P=0.032; N1/2 stage: 0.702 (0.526, 0.787) vs. 0.747 (0.663, 0.820), Z=1.68, P=0.095]. Multiple linear regression revealed that AHI explained 31.3% of the variance in nasal airflow lateralization during supine REM sleep. Conclusions: The nasal airflow regulation during sleep in OSA patients differs from that in healthy individuals. Compared with healthy subjects, OSA patients exhibit shorter nasal cycle durations, reduced nasal airflow lateralization in the supine position, and a higher likelihood of nasal cycle transitions triggered by position changes or arousal. Healthy subjects demonstrate high and stable nasal airflow asymmetry during sleep, with minimal influence from sleep stages or body position.