Nasal resistance in patients with obstructive sleep apnea.

The aim of this study was to investigate the relationship between the severity of obstructive sleep apnea (OSA) and nasal resistance (NR). Eighty-five consecutive patients were recruited owing to their symptoms indicating OSA. All patients received polysomnography and anterior rhinomanometry (performed during wakefulness in the supine position). Patients were divided into low and high NR groups according to their rhinomanometric results; their polysomnographic, anthropometric and demographic data were compared. Correlation and regression analyses were conducted to investigate the associations between polysomnography and rhinomanometric measurements. The two studied groups were not different in body mass index, sex and age (p > 0.05), but the high NR group showed a significantly higher snoring index (p = 0.03). Furthermore, unilateral higher NR correlated significantly with respiratory disturbance index (r = 0.30, p = 0.006) and minimal oxygen saturation (r = -0.22, p = 0.04); total NR also correlated with the snoring index (r = 0.23, p = 0.04). Stepwise multivariate regression models revealed that unilateral higher NR was predictive of respiratory disturbance index (R(2) = 0.087, p = 0.006). The research implied that NR is a possible contributing factor to snoring, with a need for further investigation to confirm the correlation between unilateral higher NR and the severity of OSA.