Introduction
Acute epiglottitis is a supraglottic inflammatory disease, potentially
causing life-threatening airway obstruction1. The most
commonpathogen was HaemophilusInfluenzae type b (Hib). As a result
of the introduction and widespread dissemination of the Hib vaccine in
the 1980s, the incidence of epiglottitis in the pediatric population has
dramatically dropped2,3. However, acute epiglottitis
has become a disease of adultsin the post-vaccine era, approximately
4,000 new cases per year reported in the United
States4. The mortality rates were reported from 1% to
7%5,6. Therefore, early recognition and accurate
diagnosis for adult patients are required in emergency settings.
The diagnosisof acute epiglottitis is based on clinical symptoms,
radiography, and laryngoscopy examination7,8. Sore
throat and odynophagia are the common symptoms5.
Laryngoscopy is regarded as thegold standard for
diagnosis9.However,laryngoscopy has limitations,
suchas invasiveness, inconvenience, and procedure-related airway
obstruction10.During the COVID-19 pandemic, it
represents aninfection risk for patients and a high occupational hazard
for otolaryngologists involved with the procedure11.
Also, less than 10% of patients with acute epiglottitis received
laryngoscopy in a large-scale study5. Lateral
neckradiographs are oftenused for screening in emergency departments
(EDs) for suspectedacute epiglottitis12. However,
sensitivity andspecificity vary9,13,14.
Ultrasonography (US) is a real-time, noninvasive, readily accessible
imaging diagnostic tool in the EDs.Previous studies showed that the
epiglottis couldbe identified and measured by US15-17.
However, data on the epiglottic thickness in normal individuals are
still limited15,18.
Werner et al reported that epiglottic thickness in a mixed
population including ED staff members and patients15.
However, the anteroposterior diameter of the epiglottis was
significantly different between healthy volunteers and patients,
especially in those with inflammation18. Establishing
the range of normal values of the epiglottic thickness is mandatory for
differentiating between the normal and abnormal epiglottis and for
serving as a reference for other pathologies. Whether the
epiglotticthickness varies according to raceethnicity is uncertain.
Therefore, we conducted a prospective observational study to investigate
the epiglottic thicknessmeasured by US in healthy volunteers.