title: Safety and feasibility of evaluating airway-protective reflexes during sleep: new technique and preliminary results.
abstract: BACKGROUND
  The airway is vulnerable to aspiration during sleep. The integrity of aerodigestive-protective reflexes during sleep has not been studied previously because of a lack of adequate techniques.
  
  
  OBJECTIVE
  To determine the safety and the feasibility of a new technique to elicit pharyngoglottal closure reflex (PGCR), pharyngo-upper-esophageal sphincter (UES) pressure contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS) during sleep.
  
  
  METHODS
  Outpatient sleep laboratory.
  
  
  METHODS
  PGCR, PUCR, and RPS were elicited in 3 subjects by injecting colored water into the pharynx through a specially designed UES manometry catheter to which a thin videoendoscope was taped. This assembly was passed transnasally and positioned to obtain UES-pressure recordings and adequate endoscopic glottic views. Sleep was monitored by polysomnography, and all modalities were synchronized by using a timer. Subjects were evaluated while awake and during stage I sleep.
  
  
  RESULTS
  All subjects were monitored for 3 hours of natural sleep, during which several periods of stage I sleep were observed. While awake, PGCR, PUCR, and RPS were elicited in all subjects. During sleep, PGCR was present in all, PUCR in 2, and RPS in 2 (1 after arousal) subjects. Threshold volumes for reflex elicitation were not significantly different between the awake state and stage I sleep. None of the subjects exhibited laryngeal penetration or aspiration.
  
  
  CONCLUSIONS
  Small numbers of subjects were studied only in stage I sleep.
  
  
  CONCLUSIONS
  When using the above technique, it is safe and feasible to study aerodigestive reflexes during sleep. Preliminary data suggest that PGCR, PUCR, and RPS can be elicited during sleep.
authors.affiliation: Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Kulwinder S
authors.initials: KS
authors.lastname: Dua
authors.forename: Jasmohan S
authors.initials: JS
authors.lastname: Bajaj
authors.forename: Tanya
authors.initials: T
authors.lastname: Rittmann
authors.forename: Candy
authors.initials: C
authors.lastname: Hofmann
authors.forename: Reza
authors.initials: R
authors.lastname: Shaker
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology*; D004576:Electromyography / Q000379:methods; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D049631:Esophageal Sphincter, Upper / Q000502:physiology*; D005240:Feasibility Studies; D005683:Gagging / Q000502:physiology*; D006801:Humans; D008297:Male; D008365:Manometry; D017286:Polysomnography / Q000379:methods*; D011312:Pressure; D012016:Reference Values; D015203:Reproducibility of Results; D053120:Respiratory Aspiration / Q000503:physiopathology / Q000517:prevention & control*; D012890:Sleep / Q000502:physiology*