title: [Preliminary report: observation by video laryngoscope of glottal narrowing due to cricoid pressure].
abstract: BACKGROUND
  When the applied cricoid pressure is too strong, or the place or direction of the pressure application is not appropriate, glottal closure may occur, but its details are unclear.
  
  
  METHODS
  We evaluated possible changes in the size of the rima glottides due to backward pressure on the cricoid cartilage or backward pressure or backward, upward, and rightward pressure (BURP) on the thyroid cartilage using a video laryngoscope (Fine View' Laryngoscope, Tray Medical, Tokyo) in 6 adult males and 6 females with Cormack and Lehane grade 1.
  
  
  RESULTS
  The right-to-left distance of the rima glottides was 5.1 +/- 1.2 mm without pressure application but was reduced to 3.8 +/- 1.7, 3.5 +/- 1.8, 2.8 +/- 1.9, 2.4 +/- 1.8, and 2.6 +/- 1.2 mm by 20 N and 30 N backward pressure on the cricoid cartilage and 20 N and 30 N backward pressure and BURP on the thyroid cartilage, respectively. Compared with the absence of pressure application, 20 N and 30 N backward pressure and BURP on the thyroid cartilage significantly reduced it. It was reduced to 1 mm by 30 N backward cricoid pressure in 1 patient while glottal closure occurred due to 30 backward thyroid pressure in 1 patient.
  
  
  CONCLUSIONS
  The right-to-left distance of the rima glottides was significantly reduced by backward pressure or BURP on the thyroid cartilage, and was also markedly reduced by cricoid pressure in 1 of the 12 patients.
authors.affiliation: Department of Anesthesiology, Operating Room, Shimane Prefectural Central Hospital, Izumo.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Oshima
authors.forename: Akira
authors.initials: A
authors.lastname: Sasaki
authors.forename: Harumi
authors.initials: H
authors.lastname: Kajitani
authors.forename: Atsuko
authors.initials: A
authors.lastname: Sasaki
authors.forename: Norio
authors.initials: N
authors.lastname: Niino
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsubara
mesh_terms: D000328:Adult; D000368:Aged; D003413:Cricoid Cartilage / Q000502:physiology*; D005260:Female; D005931:Glottis / Q000473:pathology*; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects; D007828:Laryngoscopy; D007829:Laryngostenosis / Q000209:etiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011015:Pneumonia, Aspiration / Q000209:etiology / Q000517:prevention & control; D011312:Pressure / Q000009:adverse effects*; D014741:Video Recording