Healthy subjects with normal nasal resistance breathe almost exclusively through the nose during sleep. This study tested the hypothesis that a mechanical advantage might explain this preponderance of nasal over oral breathing during sleep.A randomised, single-blind, crossover design was used to compare upper airway resistance during sleep in the nasal and oral breathing conditions in 12 (seven male) healthy subjects with normal nasal resistance, aged 30¡4 (mean¡SEM) yrs, and with a body mass index of 23¡1 kg?m 2 . During wakefulness, upper airway resistance was similar between the oral and nasal breathing routes. However, during sleep (supine, stage two) upper airway resistance was much higher while breathing orally (median 12.4 In a recent publication the authors described, for the first time, partitioning of inhaled ventilation between the nose and mouth during sleep in healthy subjects with normal nasal resistance [1]. The main finding of the latter study was that the oral fraction of inhaled ventilation during sleep was very small, averaging only 4% for the group of 10 subjects, and several subjects did not breathe through their mouth at all during sleep. Furthermore, the inhaled oral fraction did not change significantly between different non-rapid eye movement sleep stages or between rapid eye movement (REM) and non-REM sleep.The physiological explanation for the marked predominance of nasal ventilation over oral ventilation during sleep in normal subjects is unknown. Since total airway resistance while awake and breathing through the mouth is typically 2-4 cmH 2 O?L -1 ?s -1 [2] and the normal nasal resistance alone is of similar magnitude [3], it is not intuitively obvious why healthy subjects should choose to breathe almost exclusively through the nasal route during sleep. Specifically, there are no published measurements describing the effect of oral versus nasal breathing on upper airway resistance during sleep.It is important to understand the influence of the breathing route (oral or nasal) on upper airway resistance during sleep from the perspective of understanding normal respiratory physiology during sleep, but this information may also provide an insight into the relationship between the breathing route and upper airway obstruction during sleep. The authors hypothesised that the observed preponderance of nasal over oral ventilation in normal subjects during sleep would reflect a mechanical advantage of the nasal breathing route. To test this hypothesis, the authors compared upper airway resistance during nasal breathing and during oral breathing in healthy sleeping subjects with normal nasal resistance. Methods Study designA randomised, single blind, crossover study was conducted to compare upper airway resistance during sleep when nose breathing with that when mouth breathing. Subjects underwent a single overnight polysomnogram at Kingston General Hospital Sleep Laboratory, Ontario. The night was divided into two parts, oral breathing and nasal breathing, the order being randomised...
An association between mouth breathing during sleep and increased propensity for upper airway collapse is well documented, but the effect of treatment for nasal obstruction on mouth breathing during sleep and simultaneous obstructive sleep apnoea (OSA) severity has not been described previously.A randomised single blind placebo-and sham-controlled crossover study of treatment (topical decongestant and external dilator strip) for nasal obstruction was carried out in 10 patients (nine males; mean¡SEM 46¡5 yrs) with nasal obstruction and OSA. All patients had normal acoustic pharyngometry. The effect of treatment on nasal resistance, mouth breathing during sleep and OSA severity was quantified.Treatment of nasal obstruction was associated with a dramatic and sustained reduction in nasal resistance and the oral fraction of ventilation during sleep (mean (95% confidence interval) absolute reduction in oral fraction 30% (12-49)). Improvements in sleep architecture were observed during active treatment, and there was a modest reduction in OSA severity (change in apnoea-hypopnoea index 12 (3-22)).In conclusion, treating nasal obstruction reduced mouth breathing during sleep and obstructive sleep apnoea severity, but did not effectively alleviate obstructive sleep apnoea.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.