Effect of posture on mouth opening and modified Mallampati classification for airway assessment

Several bedside airway assessment methods have been proposed for preoperatively identifying patients who are difficult to intubate. To date, the Mallampati grading remains a time-tested technique for difficult airway assessment. Both Mallampati and the further modification by Samsoon and Young assessed patients in the seated position. During clinical practice, situations may arise where it may not be feasible for the patient to sit up for airway assessment. The aim of our prospective study was to determine whether there was any difference between the sitting and supine positions for the assessment of Mallampati grade. Eighty adult patients of American Society of Anesthesiologists (ASA) physical status I and II, aged 18-65 years, admitted to our neurosurgical ward were enrolled and assessed for airway. Our study revealed that change in posture produced a significant change in the mouth openings and Mallampati grades of the patients. This change was always toward a higher grade when the patient was turned supine from the sitting position.