title: Relationship between Oral Flow Patterns, Nasal Obstruction, and Respiratory Events during Sleep.
abstract: OBJECTIVE
  Sleep breathing patterns are altered by nasal obstruction and respiratory events. This study aimed to describe the relationships between specific sleep oral flow (OF) patterns, nasal airway obstruction, and respiratory events.
  
  
  METHODS
  Nasal flow and OF were measured simultaneously by polysomnography in 85 adults during sleep. OF was measured 2 cm in front of the lips using a pressure sensor.
  
  
  RESULTS
  OF could be classified into three patterns: postrespiratory event OF (postevent OF), during-respiratory event OF (during-event OF), and spontaneous arousal-related OF (SpAr-related OF). Postevent OFs begin at the end of airflow reduction, are preceded by respiratory arousal, and are accompanied by postapneic hyperventilation; during-event OFs occur during nasal flow reduction; and SpAr-related OFs to OF begin during stable breathing, and are preceded by spontaneous arousal but are rarely accompanied by apnea/hypopnea. Multivariate regression showed that nasal obstruction was predictive of SpAr-related OF. The relative frequency of SpAr-related OF events was negatively correlated with the apnea-hypopnea index. The fraction of SpAr-related OF duration relative to total OF duration was significantly greater in patients with nasal obstruction than in those without.
  
  
  CONCLUSIONS
  SpAr-related OF was associated with nasal obstruction, but not respiratory events. This pattern thus functions as a "nasal obstruction bypass", mainly in normal subjects and patients with mild sleep disordered breathing (SDB). By contrast, the other two types were related to respiratory events and were typical patterns seen in patients with moderate and severe SDB.
authors.affiliation: Department of Otorhinolaryngology, Teikyo University Chiba Medical Center, Tokyo, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Laboratory Medicine, Teikyo University School of Medicine, Chiba, Japan.
authors.forename: Taiji
authors.initials: T
authors.lastname: Furukawa
authors.affiliation: Department of Otorhinolaryngology, Teikyo University Chiba Medical Center, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sugimoto
authors.affiliation: Department of Otorhinolaryngology, Teikyo University Chiba Medical Center, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Katada
authors.affiliation: Department of Otorhinolaryngology, Teikyo University Chiba Medical Center, Tokyo, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kotani
authors.affiliation: Division of Respiratory Medicine, Kaname Sleep Clinic, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yoshizawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015508:Nasal Obstruction / Q000150:complications* / Q000503:physiopathology*; D017286:Polysomnography / Q000706:statistics & numerical data; D012119:Respiration; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology*; D055815:Young Adult
keywords: nasal obstruction; oral breathing; sleep disordered breathing; spontaneous arousal