Comparison Upper Lip Bite Test and Mallampati Test in the Prediction of Difficult Laryngoscopy

Background and Objective: Intubation is the most common method for the management of the upper airway in general anesthesia. In this regard, the prediction of the ease or difficulty of intubation is of paramount importance for the anesthesia team. The main cause of anesthesia-related mortality is failed airway management. The present study aimed to compare the accuracy of the upper lip bite (ULBT) test and mallampati test in the fast prediction of difficult intubation. Materials and Methods: This descriptive-analytical study was conducted on 418 patients. Prior to anesthesia, the degree of difficulty of intubation was predicted using two predictive tests, namely Mallampati test and upper lip bite test. In addition, after anesthesia, the degree of predicted difficulty was compared with the Cormack-Lehane classification of laryngoscopic view. Results: As evidenced by the obtained results, the frequency of difficult intubation was reported as 5.3%. Sensitivity, specificity, and negative predictive value of ULBT test were measured at 21.4%, 95.3%, and 97.2%, respectively. Moreover, the accuracy was obtained at 92.8% which was the highest value. On the other hand, sensitivity, specificity, and negative predictive value of Mallampati test were estimated at 34.7%, 87.5%, and 91%, respectively. In addition, the accuracy of this was reported as 81.3%. Conclusion: The results of the current study indicated that ULBT test as an easy method with high specificity, high predictive value, and high accuracy in the evaluation and prediction of difficult laryngoscopy is more suitable than Mallamati.