Background: Difficult mask ventilation is an emergency situation. In this study we pursued the effect of phonation and that of patient’s position on the Mallampati class, and its accuracy in the prediction of difficult mask ventilation.
Methods: Six hundred sixty one patients with or without phonation were examined, in both supine and upright positions. The results of the four different situations were evaluated for the prediction of difficult mask ventilation. For each of the four situations, sensitivity, specificity, positive and negative predictive values were obtained.
Results: In this study, 246 (37.2%) patients had difficult mask ventilation. The sensitivity of the Mallampati classification in four positions did not show a significant difference but the specificity was found to be the highest in the supine position with phonation. The negative predictive value was observed to be 95% in the supine position plus phonation, and the positive predictive value also had the highest percentage in the same situation.
Conclusions: The highest correlation was seen in the supine position without phonation and difficult mask ventilation. Phonation improved the Mallampati class better in the supine position than in the upright position.