Influence of Nasal Cavity Dimension and Sleep Posture on the Severity of Obstructive Sleep Apnea

Background and Objectives The aim of this study was to evaluate the effect of sleep position and nasal cavity dimension according to minimal cross-sectional area (MCA) on the severity of obstructive sleep apnea (OSA).Subjects and Method This study enrolled 528 consecutive patients who completed overnight polysomnography (PSG) and acoustic rhinometry. Positional sleep time and apnea-hypopnea index (AHI) were compared between the right and left lateral sleep positions (RLSP vs. LLSP), and between the wide and narrow lateral side sleep position (WLSP vs. NLSP) according to MCA.Results The sleep time was longer for LSP than for WLSP (20.35%±19.69% and 15.92%±16.35%, respectively) with a statistically significant difference (p=0.001). However, the AHI was not significantly different between the two groups. The sleep time was longer for RLSP than for LLSP (20.65%±19.31% and 15.39%±16.05%, respectively) with a statistically significant difference (p<0.001). In the RLSP-dominant group, there were fewer left nasal cavity narrowed patients than right nasal cavity narrowed patients (91 vs. 129, respectively). Furthermore, in the LLSP-dominant group, there were fewer right nasal cavity narrowed patients than left nasal cavity narrowed patients (60 vs. 85, respectively, p=0.001). However, we found that the AHI value was not significantly different according to sleep posture and nasal cavity dimension.Conclusion Snoring patients preferred RLSP to LLSP, and preferred to sleep on the lateral side of the narrow nasal cavity. The OSA severity was not different according to sleep position and nasal cavity dimension.