Authors : Madhurima Sinharay, Rashmee V Chavan
DOI : 10.18231/j.ijca.2019.117
Volume : 6
Issue : 4
Year : 2019
Page No : 601-606
Introduction: No anaesthesiologist like to face scenario of unanticipated difficult intubation, as it may cost
patients life. Many tests are there to predict difficult intubation, amongst those tests Modified Mallampati
test [MMT] is a gold standard test. Upper lip bite test [ULBT] is an acceptable option for predicting difficult
intubation. Our study aimed to compare both the tests to predict difficult intubation.
Objectives: To analyse positive predictive value (PPV), negative predictive value (NPV), sensitivity,
specificity and accuracy of ULBT and MMT. To compare the results of both the tests to predict difficult
intubation.
Aim: To ascertain whether ULBT can be incorporated in standard protocol of airway assessment along
with other tests to increase predictive accuracy of difficult endotracheal intubation
Materials and Methods: It was prospective randomised comparative observational study carried out
at single centre. Three hundred patients of either sex, aged between 16-60 yrs scheduled for elective
surgery under general anaesthesia with endotracheal intubation were enrolled in the study. Preoperative
evaluation of airway was done with ULBT and MMT and findings were documented.MMT class III,IV
and ULBT class III were considered as predictors of difficult intubation. On the day of the surgery
after direct laryngoscopy laryngeal view was noted and was classified according to Cormack and Lehane
classification. Patients with Cormack Lehane class III,IV considered as difficult to intubate. Cormack
Lehane classification (C &L class) redings were compared with ULBT and MMT.
Observations and Results: Demographic data and ASA grade was same for both the groups as participants
were same. By comparing ULBT with Cormack and Lehane score we got 88.46% sensitivity, 92.74%
specificity, 71.87% Positive predictive value (PPV), 97.45% ne gative predictive value (NPV) and 92%
accuracy. For MMT we go t 19.23% sensitivity, 91.93% specificity, 33.33% PPV, 84.44% NPV a nd
79.33% accuracy. Thus results showed accuracy, sensi tivity, PPV and NPV of ULBT were superior than
MMT while specificity of both the tests was similar.
Conclusion: With higher level of sensitivity, PPV, NPV and accuracy ULBT is a better choice for
predicting difficult airway than that of MMT. ULBT should be incorporated in standard airway assessment
protocol along with other tests.
Keywords: Difficult intubation, modified Mallampati test, Upper lip bite test, Cormack lehane classification.