 Han et al. have delineated the classification of a difficult airway using a four-point system, where grade 3 indicates difficult mechanical ventilation inadequate, unstable, or requiring two providers and grade 4 indicates impossible ventilation. Kheterpal et al. later showed that body mass index of 30 kgm2 or greater, a beard, Mallampati classification III or IV, age of 57 yr or older, severely limited jaw protrusion, and snoring were independent risk factors for a grade 3 airway. Snoring and thyromental distance of less than 6 cm were shown to be independent risk factors for a grade 4 airway. Both studies utilized the traditional one-handed grip or a two-handed grip when attempting mechanical ventilation. 