title: Airway length in adults: estimation of the optimal endotracheal tube length for orotracheal intubation.
abstract: OBJECTIVE
  To estimate the optimal endotracheal tube (ETT) length in orotracheally intubated patients.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Operating room of a medical center hospital.
  
  
  METHODS
  293 ASA physical status I and II patients (150 male and 143 female), requiring general anesthesia and orotracheal intubation.
  
  
  METHODS
  We used fiberoptic bronchoscope within the ETT to identify the carina and vocal cords.
  
  
  METHODS
  The length from carina to vocal cords, vocal cords to right mouth angle (corner), and carina to right mouth angle were measured. The optimal ETT tip was defined as 5 cm above the carina. Patient's height and sternum length were recorded.
  
  
  RESULTS
  The correlation between airway length and body height was significant. By linear regression, a formula was obtained to estimate the optimal ETT length in orotracheally intubated patients: the length from 5 cm above carina to right mouth angle (cm) =< body height (cm)/5> - 13.
  
  
  CONCLUSIONS
  The optimal insertion length of the ETT for orotracheally intubated adult patients with the head placed in a neutral position is correlated with body height. The proposed formula can provide a useful guide to determine the optimal ETT tip position in most of the patients who required orotracheal intubation.
authors.affiliation: Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, No. 13, Lane 61, Wan-Shou Road, Mu-Ja, 116 Taipei, Taiwan. cherng1018@sinamail.com
authors.forename: Chen-Hwan
authors.initials: CH
authors.lastname: Cherng
authors.forename: Chih-Shung
authors.initials: CS
authors.lastname: Wong
authors.forename: Che-Hao
authors.initials: CH
authors.lastname: Hsu
authors.forename: Shung-Tai
authors.initials: ST
authors.lastname: Ho
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D000886:Anthropometry; D001827:Body Height; D001999:Bronchoscopy; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D009055:Mouth / Q000033:anatomy & histology*; D011446:Prospective Studies; D014132:Trachea / Q000033:anatomy & histology*