RT Journal Article
SR Electronic
T1 Effect of nasal or oral breathing route on upper airway resistance during sleep
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 827
OP 832
DO 10.1183/09031936.03.00047903
VO 22
IS 5
A1 M.F. Fitzpatrick
A1 H. McLean
A1 A.M. Urton
A1 A. Tan
A1 D. O'Donnell
A1 H.S. Driver
YR 2003
UL http://erj.ersjournals.com/content/22/5/827.abstract
AB 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·m2. 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 cmH2O·L−1·s−1, range 4.5–40.2) than nasally (5.2 cmH2O·L−1·s−1, 1.7–10.8). In addition, obstructive (but not central) apnoeas and hypopnoeas were profoundly more frequent when breathing orally (apnoea-hypopnoea index 43±6) than nasally (1.5±0.5). Upper airway resistance during sleep and the propensity to obstructive sleep apnoea are significantly lower while breathing nasally rather than orally. This mechanical advantage may explain the preponderance of nasal breathing during sleep in normal subjects. This study was funded by grants from the William M. Spear Foundation, Queen's University and the Physicians' Service Incorporated Foundation, Ontario.