ACCURACY OF THE UPPER LIP BITE TEST;

Modified Mallampati classification in predicting difficult endotracheal intubation.

Abstract

Objective: To compare the accuracy of Upper lip bite test with modified Mallampati classification for predicting the difficult
laryngoscopic intubation. Study Design: Cross sectional Study. Place and duration of study: The study was carried out at Department of
Anaesthesiology, Intensive Care and Pain management, Combined Military hospital, Rawalpindi from September 2008 to August 2009.
Patients and Methods: Four hundred patients undergoing elective surgery meeting the inclusion/exclusion criteria were enrolled after
written informed consent. The airways of the patients were evaluated by using the modified Mallampati classification (MMP) and the
Upper lip bite test (ULBT). MMP class 3 or 4 and ULBT class 3 were considered as indicators of difficult intubation. The laryngeal view was
graded by Cormack and Lehane classification (Gold standard). Grade 1 or 2 was considered to represent easy intubation and grade 3 or 4
to represent difficult intubation. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were
calculated for both the tests separately by using the 2×2 table. Results: ULBT had a higher accuracy of 94%, specificity of 99.2% and
positive predictive value 70% compared to MMP accuracy of 82.7%, specificity of 84.4% and positive predictive value of 22.7%.
Conclusions: The diagnostic accuracy of the Upper lip bite test was more than the modified Mallampati classification. We suggest that it
be compared with the other prevailing tests as well which are often used to assess difficult intubations.