Taha Qadir Hussein a and Amir Morad Khudadad Boujan b

a Department of Anesthesia, Shar Hospital 

b Department of Surgery, College of Medicine, University of Sulaimani, Kurdistan Region, Iraq

Submitted: 15/8/2018; Accepted: 15/1/2019; Published 21/3/2019

DOI Link: https://doi.org/10.17656/jsmc.10185 



Patients need to be assessed preoperatively in order to predict difficult intubation, because difficult or failed intubation is a serious cause of morbidity and mortality. Prediction of difficult intubation lowers these risks. Modified mallampati test, upper lib bite test, thyromental distance and inter-incisor gap are used to assess difficult intubation.


To find and compare sensitivity, specificity, positive predictive value, negative predictive value of the tests alone and in combination.

Patients and Methods

We used randomized double blinded diagnostic trial for our study. We collected 130 patients of both gender who were aged more than 16 years and had an American Society of Anesthesiologists physical status of I, II, III. Moreover, the patients underwent elective and emergency operation and required tracheal intubation under general anesthesia. The study was performed at Sulaimani Teaching and Sulaimani Emergency Surgical hospitals. Furthermore, an anesthesiologist assessed the airway and documented the findings and another one did the induction. In addition, induction was standardized for all patients and the anesthesiologist recorded the Cormack and Lehane laryngoscopic view after intubation.


We found that thyromental distance has higher sensitivity (42.9%) for predicting difficult intubation but combination of all the tests increased this percent to 71.4%. Moreover, upper lib bite test had higher specificity (95.7%) to predict easy intubation, even higher than in the combination of all tests. When we combined all of the tests, sensitivity increased significantly but specificity decreased. 


Combinations of the tests together are better predictor of difficult intubation than using each test alone.

Keywords: Cormack and Lehane laryngoscopic view, Difficult intubation, Inter-incisor ga, Mallampati test, Thyromental distance, Upper lip bite test .


Cormack and Lehane laryngoscopic view, Difficult intubation, Inter-incisor gap, Mallampati test, Thyromental distance, Upper lip bite test.


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