title: Endoscopic study of mechanisms of failure of endotracheal tube advancement into the trachea during awake fiberoptic orotracheal intubation.
abstract: BACKGROUND
  Advancing the endotracheal tube (ETT) over a flexible bronchoscope (FB) during awake fiberoptic orotracheal intubation is often impeded. The goal of this study was to identify the sites and mechanisms that inhibit the passing of the ETT into the trachea.
  
  
  METHODS
  Forty-five consenting patients underwent a clinically indicated awake fiberoptic orotracheal intubation. After topical anesthesia, nerve block, or both, an awake fiberoptic orotracheal intubation was performed. The placement of the FB and advancement of the ETT over the FB were videotaped using a second nasally inserted FB. An otolaryngologist later reviewed the videotaped data.
  
  
  RESULTS
  The right arytenoid or the interarytenoid soft tissues inhibited advancement of the ETT in 42 and 11% of all patients, respectively. In all cases in which the FB was located on the right side of the larynx, failure of ETT advancement almost always occurred at the right arytenoid. Withdrawing the ETT and rotating it 90 degrees counterclockwise resulted in successful intubation on the second, third, and fourth attempts in 26.6, 20, and 0.7% of patients, respectively.
  
  
  CONCLUSIONS
  The right arytenoid frequently inhibits advancement of the ETT over the FB into the trachea during awake fiberoptic orotracheal intubation. The FB position in the larynx before tube advancement and the orientation of the ETT are relevant factors in failure of advancement of the ETT into the trachea. The authors recommend positioning the FB in the center of the larynx and orienting the bevel of the ETT to face posteriorly during the first attempt at intubation.
authors.affiliation: Department of Anesthesia, The University of Iowa, Iowa City 52242, USA.
authors.forename: Dana M
authors.initials: DM
authors.lastname: Johnson
authors.forename: Aaron M
authors.initials: AM
authors.lastname: From
authors.forename: Russell B
authors.initials: RB
authors.lastname: Smith
authors.forename: Robert P
authors.initials: RP
authors.lastname: From
authors.forename: Mazen A
authors.initials: MA
authors.lastname: Maktabi
mesh_terms: D001193:Arytenoid Cartilage / Q000033:anatomy & histology; D020680:Bronchoscopes; D001999:Bronchoscopy; D004825:Epiglottis / Q000033:anatomy & histology; D005260:Female; D005336:Fiber Optic Technology; D006801:Humans; D007442:Intubation, Intratracheal; D007823:Laryngeal Nerves; D007830:Larynx / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D019635:Neurosurgical Procedures; D014132:Trachea / Q000033:anatomy & histology*; D017211:Treatment Failure; D014743:Videotape Recording