title: A bronchoscopic, computer-assisted examination of the changes in dimension of the infant tracheal lumen with changes in head position: implications for emergency airway management.
abstract: BACKGROUND
  Resuscitation guidelines caution against extreme extension or flexion of an infant's head because tracheal obstruction may occur. No data support this recommendation. The authors therefore examined the dimensions of the tracheal lumen in neutral, extended, and flexed head positions in infants undergoing general endotracheal anesthesia for elective surgery.
  
  
  METHODS
  Eighteen healthy full-term infants were studied. A flexible fiberoptic bronchoscope was passed through a previously inserted endotracheal tube and positioned above the cricoid cartilage. Video recordings were taken in each of three head positions. Recordings were analyzed by an investigator blinded to head position. A computer-digitized technique was used to measure anterior-posterior and lateral dimensions and cross-sectional area. Data were analyzed using paired t tests and sign tests.
  
  
  RESULTS
  No significant differences in mean tracheal dimensions with changes in head position were found. No infant had complete tracheal obstruction. Infants were equally as likely to have a small increase as they were to have a small decrease in tracheal dimension with changes in head position.
  
  
  CONCLUSIONS
  Despite the belief that infants and neonates have obstruction at the level of the trachea with extreme positions of the head, the authors were unable to demonstrate this phenomenon.
authors.affiliation: Department of Pediatric Anesthesiology, Children's Memorial Hospital, Chicago, Illinois 60614, USA. mwheeler@nwu.edu
authors.forename: M
authors.initials: M
authors.lastname: Wheeler
authors.forename: A G
authors.initials: AG
authors.lastname: Roth
authors.forename: M E
authors.initials: ME
authors.lastname: Dunham
authors.forename: B
authors.initials: B
authors.lastname: Rae
authors.forename: C J
authors.initials: CJ
authors.lastname: Coté
mesh_terms: D000402:Airway Obstruction / Q000209:etiology* / Q000628:therapy; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D001999:Bronchoscopy; D004630:Emergencies; D005260:Female; D005336:Fiber Optic Technology; D006221:Halothane; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011187:Posture; D011446:Prospective Studies; D012151:Resuscitation / Q000379:methods; D016037:Single-Blind Method; D014132:Trachea / Q000033:anatomy & histology* / Q000502:physiology; D014741:Video Recording / Q000379:methods
chemical_list: D018685:Anesthetics, Inhalation; D006221:Halothane