title: Comments to Role of upper airway ultrasound in airway management.
abstract: Tracheal ultrasound can be an alternative diagnostic tool in airway management, besides traditional confirmatory methods such as capnography and auscultation. The standard image is a hyperechoic air-mucosa (A-M) interface with a reverberation artifact posteriorly (comet-tail artifact). If the second A-M interface appears, which we call a "double-tract sign," esophageal intubation is considered.
authors.affiliation: Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Hsin-Chu Branch, No.25, Lane 442, Sec.1, Jingguo Rd, Hsinchu City 300, Taiwan.
authors.forename: Wan-Ching
authors.initials: WC
authors.lastname: Lien
keywords: Airway; Air–mucosa interface; Double-tract sign; Ultrasound