title: Bedside prediction of airway length by measuring upper incisor manubrio-sternal joint length.
abstract: BACKGROUND
  Malpositioning of endotracheal tube may lead to serious complications like endobronchial intubation or accidental extubation. Using anatomical measurements for prediction of airway length would be more practical in resource constrained settings.
  
  
  METHODS
  One hundred adult patients of American Society of Anesthesiologists (ASA) grade 1 or 2, without any evidence of difficult airway, were randomly allocated to two cohorts - a model cohort of 70 (50 males) and test cohort of 30 (20 males) subjects. Height, the straight length from the upper incisor to manubrio-sternal joint in fully extended head position (IncManustL), the length from upper incisor to the carina in neutral head position (IncCarinaL), and degree of neck extension were measured in all subjects. Relationship between the two lengths in the model cohort was explored by Pearson's coefficient (r). Predictions were made for subjects in the test cohort and actual and predicted values assessed for agreement using intra-class correlation coefficient (ICC).
  
  
  RESULTS
  Good agreement was found between IncManustL and IncCarinaL for both male (r = 0.69) and female (r = 0.54) subjects. Multiple regression analysis suggested height to be another significant predictor, unlike age, weight, and neck extension. The gender-specific regression equations were used to predict IncCarinaL for the test cohort. ICC for absolute agreement between the actual and predicted values was 0.723 (95% CI 0.495-0.858).
  
  
  CONCLUSIONS
  It is possible to predict airway length in adult Indian subjects by making two simple anatomical measurements, namely stature and incisor manubrio-sternal joint length.
authors.affiliation: Department of Critical Care Medicine, Apollo Gleneagles Hospital, Kolkata, West Bengal, India.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Principal, Burdwan Medical College, Burdwan, West Bengal, India.
authors.forename: Manjushree
authors.initials: M
authors.lastname: Ray
authors.affiliation: Department of Anaesthesiology, Nil Ratan Sircar Medical College, Kolkata, West Bengal, India.
authors.forename: Rita
authors.initials: R
authors.lastname: Pal
keywords: Airway length prediction; incisor carina length; upper incisor manubrio-sternal joint length