Statistical analysis
The sample size was estimated by using PASS 2019 software (NCSS software, Kaysville, Utah, USA). The sample size was calculated to be at least 112 to achieve a power of 0.9 under the significance level of 5%. Cohen’s kappa statistic (Κ) was calculated, which reflected the inter-rater reliability for the measurements.
Participant data weredeidentified before data cleaning and statistical analysis.All data were analyzed by SAS software (SAS 9.4, Cary, North Carolina, USA). Student t-test was used for continuous data and the Chi-square test was used for categorical variables. A p-value of less than 0.05 was considered significant. Linear regression models were employed to identify parameters to be associated with the epiglottic thickness significantly and independently. Covariates in the model were age, sex, height, weight, and BMI. Coefficients and 95% confidence intervals (CIs) were computed.