title: Laryngeal constriction during hypoxic gasping and its role in improving autoresuscitation in two mouse strains.
abstract: Laryngeal closure following hypoxic gasps has been documented, but its efficacy in improving autoresuscitation capacity is unknown. We studied SWR/J mice who normally cannot autoresuscitate and the C57/BLJ strain who can. We evaluated the effects of elevated end-inspiratory lung volume immediately following a gasp. We compared upper airway-intact mice with tracheostomized mice in which the vocal cords are bypassed. We used the techniques of repeated autoresuscitate trials to test autoresuscitation capability. Both SWR/J and C57/BLJ mice could maintain elevated lung volume immediately after a gasp (breath holding). Such breath holding increased autoresuscitation ability in C57/BLJ mice but did not in SWR/J mice. In SWR/J mice, the duration of the breath holds was less than that in the C57/BLJ mice. These findings indicate that gasp-associated breath holding improves autoresuscitation capability during repeated autoresuscitation trials. Also, they show that SWR/J mice have a deficiency in central nervous system mechanisms regulating glottic closure during hypoxic gasping.
authors.affiliation: Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Song
authors.forename: K A
authors.initials: KA
authors.lastname: Harris
authors.forename: B T
authors.initials: BT
authors.lastname: Thach
mesh_terms: D000818:Animals; D003250:Constriction; D004594:Electrophysiology; D000860:Hypoxia / Q000503:physiopathology*; D007830:Larynx / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D010366:Peak Expiratory Flow Rate; D015656:Respiratory Mechanics / Q000502:physiology; D012151:Resuscitation; D014139:Tracheostomy