Effects of position and phonation on oropharyngeal view and correlation with laryngoscpic view

To evaluate the effects of phonation and various head and body positions on oropharyngeal view (Mallampati score), and the correlation of these with laryngoscopic view, using the Cormack and Lehane score.

Four hundred (390) consecutive patients were evaluated in the wards during preoperative anaesthetic review. During airway assessment, the patients were placed in various head and body positions to determine oropharyngeal structures visualized, with and without phonation, according to the Mallampati test score. In the operating theatre, laryngoscopic view scores (according to Cormack and Lehane) were recorded, and the various scores analyzed.

Phonation consistently improved the Mallampati scores in all the head and body positions. The scores were better in the supine position compared to the sitting position. The best correlation of the Mallampati score with the Cormack and Lehane score was in the sitting, head maximally extended position, without phonation. Extention of the head improved the score in the sitting position, but not in the supine position. Phonation reduced the correlation of the scores in all the positions.

We conclude that the best position to conduct the Mallampati test is sitting, head maximally extended, without phonation. This correlated best with laryngoscopic view score in our study.