Predictive value of upper lip test compared with the Mallampati classification to predict difficult intubation in obstetric patients

Abstract

Difficult laryngoscopy and intubation can cause dangerous sequel for the patient if not promptly managed. So, studies try to find the predictive test with higher accuracy in defining difficult airway. This problem is more common and problematic in obstetric patients. So we aimed to compare the ULBT with MMLT in prediction of difficult airway in obstetric patients. Materials & Methods: After obtaining ethics' committee approval, 184 adult pregnant women with ASA physical status of I or II, were enrolled in this prospective observational single blind study. Exclusion criteria were morbid obese patients (BMI>35), inability for mouth opening, patients with restricted neck movement, edentulous women, those with airway malformation and those who were unable to stand erect or sit. Difficult laryngoscopy in this study was defined as Cormack and Lehane grade III and IV. ULBT, TMD and SMD tests were noted for all patients. Results: MMT, ULBT and SMD had the highest sensitivity respectively which showed that these tests can be used as a good tests for prediction of difficult airway. Based on regression analysis, BMI and Cormack-Lehane have a significant association. (P value: 0.03). MMT was the most accurate test for prediction of difficult airway in this study. The best cut-off points of thyromental and sternomental distances for predicting difficult airway in our study were 5 cm and 15 cm respectively by ROC curve analysis.