title: Arousal from sleep does not lead to reduced dilator muscle activity or elevated upper airway resistance on return to sleep in healthy individuals.
abstract: OBJECTIVE
  To compare changes in end-tidal CO2, genioglossus muscle activity and upper airway resistance following tone-induced arousal and the return to sleep in healthy individuals with small and large ventilatory responses to arousal.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Two sleep physiology laboratories.
  
  
  METHODS
  35 men and 25 women with no medical or sleep disorders.
  
  
  METHODS
  Auditory tones to induce 3-s to 15-s cortical arousals from sleep.
  
  
  RESULTS
  During arousal from sleep, subjects with large ventilatory responses to arousal had higher ventilation (by analytical design) and tidal volume, and more marked reductions in the partial pressure of end-tidal CO2 compared to subjects with small ventilatory responses to arousal. However, following the return to sleep, ventilation, genioglossus muscle activity, and upper airway resistance did not differ between high and low ventilatory response groups (Breath 1 on return to sleep: ventilation 6.7±0.4 and 5.5±0.3 L/min, peak genioglossus activity 3.4%±1.0% and 4.8%±1.0% maximum, upper airway resistance 4.7±0.7 and 5.5±1.0 cm H2O/L/s, respectively). Furthermore, dilator muscle activity did not fall below the pre-arousal sleeping level and upper airway resistance did not rise above the pre-arousal sleeping level in either group for 10 breaths following the return to sleep.
  
  
  CONCLUSIONS
  Regardless of the magnitude of the ventilatory response to arousal from sleep and subsequent reduction in PETCO2, healthy individuals did not develop reduced dilator muscle activity nor increased upper airway resistance, indicative of partial airway collapse, on the return to sleep. These findings challenge the commonly stated notion that arousals predispose to upper airway obstruction.
authors.affiliation: University of Melbourne, Parkville VIC, Australia: Institute for Breathing and Sleep, Heidelberg VIC, Australia.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Jordan
authors.affiliation: University of Melbourne, Parkville VIC, Australia: Institute for Breathing and Sleep, Heidelberg VIC, Australia.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Cori
authors.affiliation: University of Melbourne, Parkville VIC, Australia: : Institute for Breathing and Sleep, Heidelberg VIC, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Dawson
authors.affiliation: University of Melbourne, Parkville VIC, Australia.
authors.forename: Christian L
authors.initials: CL
authors.lastname: Nicholas
authors.affiliation: University of Melbourne, Parkville VIC, Australia: Institute for Breathing and Sleep, Heidelberg VIC, Australia.
authors.forename: Fergal J
authors.initials: FJ
authors.lastname: O'Donoghue
authors.affiliation: Adelaide Institute for Sleep Health, Daw Park, SA, Australia: Flinders University, Bedford Park SA, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Catcheside
authors.affiliation: Neuroscience Research Australia (NeuRA) and the University of New South Wales, Randwick NSW, Australia.
authors.forename: Danny J
authors.initials: DJ
authors.lastname: Eckert
authors.affiliation: Adelaide Institute for Sleep Health, Daw Park, SA, Australia: Flinders University, Bedford Park SA, Australia.
authors.forename: R Doug
authors.initials: RD
authors.lastname: McEvoy
authors.affiliation: University of Melbourne, Parkville VIC, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Trinder
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D001143:Arousal / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D012119:Respiration; D012137:Respiratory System; D012890:Sleep / Q000502:physiology*; D013990:Tidal Volume; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Upper airway collapse; genioglossus; obstructive sleep apnea; pharyngeal airway