title: Front teeth-to-carina distance in children undergoing cardiac catheterization.
abstract: BACKGROUND
  Knowledge of normal front teeth-to-carina distance (FT-C) might prevent accidental bronchial intubation. The aim of the current study was to measure FT-C and to examine whether the Morgan formula for oral intubation depth, i.e., endotracheal tube (ETT) position at front teeth (cm) = 0.10 x height (cm) + 5, gives appropriate guidance when intubating children of different ages.
  
  
  METHODS
  FT-C was measured in 170 infants and children, aged 1 day to 19 yr, undergoing cardiac catheterization. FT-C was obtained as the sum of the ETT length at the upper front teeth/dental ridge and the distance from the ETT tip to the carina. The latter measure was taken from an anterior-posterior chest x-ray.
  
  
  RESULTS
  There was close linear correlation between FT-C and height: FT-C (cm) = 0.12 x height (cm) + 5.2, R = 0.98. The linear correlation coefficients (R) for FT-C versus weight and age were 0.78 and 0.91, respectively. If the Morgan formula had been used for intubation, the ETT tip would have been at 90 +/- 4% of FT-C. No patient would have been bronchially intubated, but the ETT tip would have been less than 0.5 cm from the carina in 13 infants.
  
  
  CONCLUSIONS
  FT-C can be well predicted from the height/length of the child. The Morgan formula provides good guidance for intubation in children but can result in a distal ETT tip position in small infants. Careful auscultation is necessary to ensure correct tube position.
authors.affiliation: Department of Anesthesiology, Eastern Maine Medical Center, Bangor, Maine, USA.
authors.forename: Agnes I
authors.initials: AI
authors.lastname: Hunyady
authors.forename: Benjamin
authors.initials: B
authors.lastname: Pieters
authors.forename: Troy A
authors.initials: TA
authors.lastname: Johnston
authors.forename: Christer
authors.initials: C
authors.lastname: Jonmarker
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D001837:Body Weights and Measures / Q000379:methods* / Q000706:statistics & numerical data*; D001980:Bronchi / Q000033:anatomy & histology; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007442:Intubation, Intratracheal / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D008297:Male; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic; D012737:Sex Factors; D014070:Tooth / Q000033:anatomy & histology; D014132:Trachea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*