Discussion
This study evaluated the epiglotticthickness measured by US in healthy Chinese adults. The results showed that male gender and higher BMI were positively related to the thicker epiglottis. Also, Chinese adults had thinner epiglottisthan Americans15.
US is a real-time, noninvasive, non-radiated, readily accessible imaging modality. With such characteristics, US can play an important role in screening and diagnosis in the EDs.It has a wide range of applications such as cardiopulmonary resuscitation, shock evaluation, and airway management20-22. This study demonstrates the feasibility of US for evaluation of the epiglottis. It could be a supplementary examination for patients with suspected acute epiglottitis, in addition to conventional radiography. Also, it would be more suitable than laryngoscopy during the COVID-19 pandemic. Moreover, US had a greater value for patients having hemodynamic instability or severe dyspnea in difficulties to obtain optimal radiographs18.
Evidence regarding US evaluation of epiglottis for healthy adults is still limited. Werner et al reported thickness among the normal American subjects and patients15. Koet al have reported the sonographic thickness of the epiglottis among Korean adults18. Comparing with their results, this studyshowed the epiglottisin healthy Chinese adults was thinner than that in Americans.
The current study provides comparability between genders that the numbers of men and women were approximately equal.Also, it not only included obese volunteers but also stratified them according to their BMI. The results showed male gender and higher BMI were independent predictors for the epiglotticthickness, although gender had a greater impact.Reviewing the literature, menhave been reported to have a thicker epiglottis than women15,23. Male gender and BMI>25.0 kg/m2were significantly associated with severe epiglottitis24. Whether thicker epiglottis related to a higher incidence of epiglottitis in men5,9,25 is uncertain. Moreover, whether thicker epiglottis in men and subjects with higher BMI has more chances to develop severe epiglottitis needs further investigation.
To the best of our knowledge, this is the first study to investigate the epiglottic thickness in healthy Chinese adults. Independent predictors such as gender and BMI were identified. Race ethnicity would exist in the epiglottic thickness.
Despite these contributions, this study has several limitations. First, the results were obtained from one single institution. However, the sample size and the power of the study were statistically sufficient. Second, US is an operator-dependent imaging modality. The bias could be eliminated through supervision by a senior instructor. Additionally, Cohen’s kappa in the current study was 0.87, which implied good consistency between operators for the epiglottic measurements. Third, data regarding race-ethnicity were obtained from previous studies. Future multicenteror international studieswould be conducted for validation or investigation for race differences.