Fig. 3

Comparison of maximum applied forces on tongue by each laryngoscope and airway adjunct. Column scatter plots representing the data distribution (circles), mean (horizontal bar), and standard deviation (vertical bar). The P values were derived from two-way analysis of variance. n = 209 in each group. DL: direct laryngoscope; ETI: endotracheal intubation; GEB: gum-elastic bougie; VL: video laryngoscope