Dichotomous Physiological Effects of Nocturnal External Nasal Dilation in Heavy Snorers: The Answer to a Rhinologic Controversy?

Abstract

The purpose of this article was to study the impact of external dilation on nasal airway dimensions, sleep architecture, and snoring. Eighteen heavy snorers without severe obstructive sleep apnea syndrome (mean apnea-hypopnea index (AHI) 9.3) reporting nocturnal nasal obstruction were enrolled in a randomized (controlled) cross-over study, evaluating subjective and objective effects of external nasal dilation (Breathe Right, 3M). The active dilator was also worn during a one-week pretrial run-in period. Polysomnography, recording of snoring sounds, and repeated acoustic rhinometry were performed on two consecutive nights, one with the active dilator and one with a placebo strip. The significant subjective improvement reported during the run-in period compared to the preceding period without dilator (p < 0.01), remained only for nasal patency (p < 0.05) when comparing the two nights in the sleep laboratory. The nasal dimensions increased significantly (p < 0.001) with the active dilator compared to placebo, both in the evening and the next morning. In a subgroup (n = 6) of habitual snorers (AHI < 10) with severe morning obstruction (combined minimal cross-sectional area < 0.6 cm²), external dilation significantly improved the mean sleep PaSO₂ (92.4 å 96.7) and the percentage of sleep with a PaSO₂ < 95% (49.9% å 4.9%) (p < 0.05). In this subgroup there was a trend toward reduction in (7.4 å 5.4) (p = 0.06), whereas the AHI increased significantly in the group of 12 with larger nocturnal nasal dimensions (p < 0.05). Duration and intensity of snoring remained unchanged regardless of the subgrouping. Objective beneficial effects were restricted to nocturnal oxygen saturation and AHI in a subgroup of habitual heavy snorers identified by repeated acoustic rhinometry, in whom external dilation objectively relieved marked nocturnal nasal obstruction. This finding may provide a logical explanation for the conflicting results of medical, surgical, and mechanical expansion of the nasal dimensions on snoring and sleep disturbances.