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.