Measurements of the epiglottic thickness
A SSA-780A ultrasound scanner (Canon, Japan) equipped with a 7-12 MHz
linear transducer was used. Participants lied in the supine position
with their neckextended slightly. The sonographers identified the
thyroid and cricoid cartilage and gently moved the linear probe
superiorly. After tilting the probe, the epiglottis appeared (Figure 1).
The epiglottic thickness was determined at three sites: midpoint, right
edge, and left edge. The thickness on each edge was determined at a
fixed distance from the midpoint18.
The epiglottic thickness was measured by two independent physicians who
were well-instructed and qualified for airway US after a 1-h standard
lecture and 8-h hands-on practice. Each sonographer measured the
epiglottic thickness at each site for three times. The measurements were
supervised and confirmed by a senior physician with more than 10 years
of experience in sonographic examinations and certification from the
Society of Ultrasound in Medicine (Blinded for review).