title: Effect of nasal high-flow oxygen therapy on the swallowing reflex: an in vivo volunteer study.
abstract: OBJECTIVE
  The advantages of nasal high-flow oxygen therapy (NHF) include not only allowing talking, but also eating and drinking, during the therapy. However, the effect of NHF on the swallowing reflex remains unclear. In the present study, we aimed to assess the effects of NHF on the swallowing reflex.
  
  
  METHODS
  Nine healthy adult Japanese male volunteers with no history of dysphagia or diseases that may cause dysphagia, such as stroke or Parkinson's disease, were evaluated. Participants received one of four levels of NHF intervention (0 (control), 15, 30 and 45 L/min of oxygen) with the NHF system through the nasal cannula. Swallowing was induced by the administration of a bolus injection of 5 mL of distilled water over 3 s through a polyethylene catheter at each level of oxygen flow. The primary end-point was the latency period of the swallowing reflex after bolus injection, which was defined as the time from the start of the bolus injection to the onset of the electromyogram (EMG) burst of the first swallow.
  
  
  RESULTS
  Mean latency times of the swallowing reflex with 15 (9.8 ± 2.9 s), 30 (9.0 ± 2.7 s) and 45 (8.5 ± 3.0 s) L/min of NHF were significantly shorter than those under control conditions (11.9 ± 3.7 s; P < 0.05).
  
  
  CONCLUSIONS
  Our study demonstrates that NHF may enhance swallowing function with increasing levels of NHF by reducing the latency of the reflex.
  
  
  CONCLUSIONS
  NHF may allow continuation of oral intake without aspiration during oxygen therapy.
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan. sanuki@nagasaki-u.ac.jp.
authors.forename: Takuro
authors.initials: T
authors.lastname: Sanuki
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan.|Department of Dental Anesthesiology, Nagasaki University Hospital, Nagasaki, 852-8523, Japan.
authors.forename: Gaku
authors.initials: G
authors.lastname: Mishima
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan.|Department of Dental Anesthesiology, Nagasaki University Hospital, Nagasaki, 852-8523, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kiriishi
authors.affiliation: Department of Special Care Dentistry, Nagasaki University Hospital, Nagasaki, 852-8523, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Okayasu
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Department of Dental Anesthesiology, Nagasaki University Hospital, Nagasaki, 852-8523, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kurata
authors.affiliation: Division of Clinical Physiology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8523, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Ayuse
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology*; D004576:Electromyography; D064368:Healthy Volunteers; D006801:Humans; D007564:Japan; D008297:Male; D009666:Nose; D010102:Oxygen Inhalation Therapy / Q000379:methods*
keywords: Airway protective reflexes; Nasal high-flow oxygen therapy; Oxygen therapy; Swallowing reflex