The Effect of Different Positions on Determining the Modified Mallampati Class in Order to Predict the Difficulty of Ventilation with Mask, and the Laryngoscopy Grade and Difficult Intubation in Candidates for Surgery

Inadequate ventilation with mask and difficult intubation are the most common adverse respiratory outcomes in patient undergoing anesthesia .The aim of this study was to compare Mallampati test in different sitting positions in traditional approach and during phonation for predicting difficult laryngoscopy and intubation in candidates for surgery.

In this diagnostic value study on 385 patients, in different positions and sitting with open mouth and closed mouth, Mallampati test was examined by a blind person regarding the condition of the mallmpati, laryngoscopy grade, and the severity of intubation. The results of these four positions of mallampati were compared in predicting laryngoscopy grade and the severity of intubation.

All mallampati test scenarios had acceptable diagnostic value (P < 0.001). The accuracy of the Mallampati test in supine position with open mouth was lower than in other cases, and in the both positions of sitting with abeslang and supine with open mouth, diagnostic values were not suitable for assessing difficult and comfortable mask ventilation (P > 0.050). Mallampati test accuracy in supine position with open mouth was less than other positions. However, with a low accuracy, this position had the highest sensitivity (100%). The negative predictive value in all mallampati test cases was higher than 98%, and the positive predictive value of sitting with open mouth was higher than other positions with the value of 4.7%.

 According to the results of this study, the Malamapati test in the position of supine with abeslang was better in determining the severity of laryngoscopy and intubation.</div>