Randomized Placebo-controlled Cross-over Trial of the Effect of Nasal Tramazoline With Dexamethasone in Obstructive Sleep Apnoea Patients

Nasal obstruction impairs sleep quality and may predispose to snoring and obstructive sleep apnoea (OSA) [1]. Indeed, in healthy subjects, experimental nasal occlusion has been shown to elicit obstructive apnoeas [2]. Additionally, in patients with OSA nasal obstruction is considered a risk factor for the development of OSA [3].

Despite the relationship between nasal obstruction and OSA, the therapeutic effect of improving nasal airway patency on OSA severity remains a point of conjecture [4]. In fact, administration of intranasal corticosteroids has been shown to improve sleepiness and reduce the apnoea/hypopnoea index (AHI) in patients with OSA and rhinitis [5], whereas in OSA patients with nasal obstruction the use of topical decongestants, external nasal dilators and nasal surgery has provided equivocal results [6].

The present authors have demonstrated a strong correlation between apnoea-hypopnoea index and oral/oro-nasal breathing epochs in patients with OSA and normal nasal resistance [7]. Additionally, Kohler et al [8] have shown that nasal resistance may increase during sleep reflecting substantial variability. Therefore, it is plausible to hypothesize that OSA patients presenting with normal nasal resistance when they are awake may demonstrate increased nocturnal nasal resistance during sleep that may predispose to oral/oro-nasal breathing and elicit apnoea/hypopnoeas. Prevention of nocturnal nasal obstruction in such OSA patients may decrease oral/oro-nasal breathing and eventually be beneficial for OSA by decreasing apnoea/hypopnoeas. Thus, the present study aims to investigate whether the pharmacological prevention of nasal obstruction could alter breathing route pattern and lead to a decrease in the number of apnoea/hypopnoeas in OSA patients with normal nasal resistance.

The study will include two nasal treatment options. Firstly, a combination of a nasal decongestant (tramazoline) with a nasal corticosteroid (dexamethazone). Tramazoline (imidazoline derivative) is a nasal decongestant, which attains its maximal effect between 30 and 210 min after application [9], while nasal dexamethasone can attenuate nasal inflammation associated with OSA [10]. Secondly, sodium chloride (0.9% solution).

OSA patients (AHI>10 events/h) with normal nasal resistance measured in seated and supine position with active anterior and posterior rhinomanometry (<3.0 cmH20•L-1•s) will be recruited. Exclusion criteria will be considered: 1) recent surgery involving the upper airways, 2) central apnoeas more than three per hour or five percent of total apnoeas, 3) total sleep time during polysomnographies less than three hours, 4) current treatment with nasal decongestants and topical steroids, and 5) upper or lower respiratory tract disease, including a history of nasal allergy, and 6) smoking.