title: Comparison between different tests and their combination for prediction of difficult intubation: An analytical study.
abstract: BACKGROUND
  There is an impelling need for accurate tests to predict difficult intubation, as failure to achieve endotracheal intubation causes significant morbidity and mortality in anesthetic practice.
  
  
  OBJECTIVE
  To calculate the validity of the different tests along with their combination and agreement when compared with endotracheal intubation in predicting difficult intubation.
  
  
  METHODS
  Operation theaters, analytical study.
  
  
  METHODS
  Three hundred patients aged between 16 and 60 years of American society of anesthesiologist (ASA) physical status I and II, scheduled for elective surgical procedures requiring endotracheal intubation were studied during January-July 2012. Mallampati grade (MP), sternomental distance (SMD), thyromental distance (TMD), and Delilkan and Calder test were recorded for every patient. Endotracheal intubation was performed by an experienced anesthesiologist blinded to the measurements and recorded grading of intubation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR), odds ratio (OR), and kappa coefficient of tests individually and in combination were calculated.
  
  
  METHODS
  IBM SPSS software (version 16.0) and Epi-info software (version 3.2).
  
  
  RESULTS
  Difficult and failed intubation was 13.3% and 0.6%, respectively. Difficult intubation increased with age. TMD and Calder test showed highest sensitivity individually and Dellilkan's test showed least sensitivity. Among the combination of tests, MP with SMD and MP with Calder test had the highest sensitivity.
  
  
  CONCLUSIONS
  Among individual test TMD and Calder are better predictive tests in terms of sensitivity. Combination of tests increases the chance of prediction of difficult intubation.
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Sandip Roy
authors.initials: SR
authors.lastname: Basunia
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Sarmila
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Susmita
authors.initials: S
authors.lastname: Bhattacharya
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Indranil
authors.initials: I
authors.lastname: Saha
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Atanu
authors.initials: A
authors.lastname: Biswas
authors.affiliation: Department of Anaesthesiology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.
authors.forename: Anu
authors.initials: A
authors.lastname: Prasad
keywords: Delilkan and Calder test; Mallampati grade; difficult intubation; sternomental and thyromental distance