title: Nasal obstruction and sleep-disordered breathing: the effect of supine body position on nasal measurements in snorers.
abstract: OBJECTIVE
  Nasal obstruction is considered to be a potential etiological factor in sleep-disordered breathing. However, a significant correlation between nasal measurements and obstructive sleep apnea has not been demonstrated so far. The aim of this study was to investigate the relationships between nasal resistance, nasal volumes and selected sleep parameters using nasal measurements performed in both seated and supine positions. We also investigated whether snoring patients in our clinical sample showed increased positional or decongestive nasal mucosal changes.
  
  
  METHODS
  Forty-one snoring men on a waiting list for correction of nasal obstruction underwent polysomnography, anterior rhinomanometry and acoustic rhinometry. Nineteen non-snoring control subjects were also recruited. Nasal measurements were performed in a seated position, after lying down in a supine position and, after decongestion of nasal mucosa, in a seated position again.
  
  
  RESULTS
  In the overall patient group, nasal volume at a distance 2-4 cm from the nares in the supine position correlated inversely with apnea-hypopnea index (AHI) (r = -0.32, p < 0.05) and oxygen desaturation index (ODI) (r = -0.49, p < 0.05). In the non-obese patients, total nasal resistance measured in a supine position correlated with AHI (r = 0.50, p < 0.05) and ODI (r = 0.58, p < 0.05) and supine nasal volumes were also inversely correlated with ODI. No significant correlations were found between baseline nasal measurements performed in a seated position and sleep parameters. Postural or decongestive changes in nasal measurements were not increased in snoring patients compared with control subjects.
  
  
  CONCLUSIONS
  The relationship found between nasal measurements and sleep parameters suggests that nasal obstruction does augment airway collapse.
authors.affiliation: Department of Otorhinolaryngology--Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland. paula.virkkula@hus.fi
authors.forename: Paula
authors.initials: P
authors.lastname: Virkkula
authors.forename: Paula
authors.initials: P
authors.lastname: Maasilta
authors.forename: Maija
authors.initials: M
authors.lastname: Hytönen
authors.forename: Tapani
authors.initials: T
authors.lastname: Salmi
authors.forename: Henrik
authors.initials: H
authors.lastname: Malmberg
mesh_terms: D000328:Adult; D000403:Airway Resistance; D006801:Humans; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000503:physiopathology; D015508:Nasal Obstruction / Q000503:physiopathology*; D017286:Polysomnography; D025363:Rhinomanometry; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D012913:Snoring / Q000503:physiopathology*; D016683:Supine Position