Fig. 1

The schema and fluoroscopic X-ray image of the U-shape ETT with the sagittal section of the airway. The ETT is bent in a U-shape (a). After carefully raising the epiglottis directly by the blade of the laryngoscope (b), insert the U-shaped ETT with the image of raising up the tongue (c–e). The four small black arrows in b indicate the body of the laryngoscope, the dotted lines indicate its blade, and the solid lines indicate the ETT. As the stylet was gently removed, the tip of the ETT was automatically advanced (e, f). ETT, endotracheal tube