title: Detection of increased upper airway resistance during overnight polysomnography.
abstract: OBJECTIVE
  To examine the utility of four methods used to detect increased upper airway resistance leading to arousal from sleep.
  
  
  METHODS
  Ten overnight sleep studies were conducted on normal subjects who reported increased snoring and/or witnessed apneas following alcohol ingestion. Alcohol was used to increase upper airway resistance in these normal subjects before ovemight polysomnography. Four methods to detect the presence of increased upper airway resistance were used: esophageal pressure manometry; respiratory inductive plethysmography; a piezoelectrically treated stretch sensor adhered to the supraclavicular fossa; nasal flow measured with oxygen cannula and differential pressure transducer.
  
  
  METHODS
  Private Sleep Laboratory.
  
  
  METHODS
  Ten normal, healthy volunteers (5 male, 5 female).
  
  
  METHODS
  Alcohol ingestion as red wine (14% alcohol), 180-540 mL one to two hours before overnight polysomnography. Esophageal catheterisation.
  
  
  RESULTS
  Two hundred twenty-seven electroencephalogram arousals were preceded by inspiratory flow limitation and/or increased respiratory effort. Flattening of the nasal flow profile preceded all 227 arousals. In contrast, only 40% of arousals were preceded by an increase in the size of the stretch sensor signal, 22% by more-negative deflection of the esophageal pressure signal and 21% by increase in the signal size of respiratory inductance plethysmography.
  
  
  CONCLUSIONS
  These findings indicate that the most reliable method of detecting increased upper airway resistance leading to arousal from sleep is the nasal cannula/pressure transducer method and suggest that many arousals induced by increased upper airway resistance may be caused by mechanoreceptor afferents.
authors.affiliation: David Read Laboratory, Department of Medicine, University of Sydney, NSW, Australia. pamelaj@med.usyd.edu.au
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Johnson
authors.forename: Natalie
authors.initials: N
authors.lastname: Edwards
authors.forename: Keith R
authors.initials: KR
authors.lastname: Burgess
authors.forename: Colin E
authors.initials: CE
authors.lastname: Sullivan
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D002940:Circadian Rhythm; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods*; D012895:Sleep, REM / Q000502:physiology; D013997:Time Factors