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.