Dr. Veena Kachhwah, Dr. Neeraj Narang


BACKGROUND: We prospectively compared the Upper Lip Bite Test with Inter Incisor Distance to predict difcult
endotracheal intubation.
METHOD: Two anaesthesiologist, not involved in intubation of airway of the patients, evaluated airway by using upper lip bite test (ULBT) and
inter incisor distance (IID). Laryngoscopy and intubation performed by another anaesthesiologist, he assessed the laryngeal view and graded
according to the Cormack-Lehane grading system. Sensitivity, specicity, accuracy, positive value, negative predictive value, internal
consistancy were calculated for each test.
RESULTS: Upper Lip Bite Test is proved to be more sensitive in difcult intubation prediction (54.3%) in comparison to Inter Incisor Distance
(9.6%). However Upper Lip Bite Test is found to be less specic (45.6%) to rule out easy intubations than Inter Incisor Distance (95.1%)
CONCLUSION: We found that ULBT is more sensitive to anticipate difcult intubation than the IID. Nevertheless IID is more specic to
predict easy intubations than the ULBT. Hence we feel that it would be better if we use IID rst to rule out easy intubations as it is more specic
than we can apply ULBT to the patients who's airway is predicted as difcult by the IID, to predict true cases of difcult airway.


Upper Lip Bite Test, Inter Incisor Distance, endotracheal intubation, difcult intubation

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