Statistical studies:
We compared demographic, clinical and procedure related characteristics as well as outcomes between children who underwent rigid and flexible bronchoscopy using appropriate univariate analyses. Specifically, nominal variables were compared using Pearson’s chi-square test, continuous variables that matched parametric criteria were compared by using Student’s t-test, and ordinal variables and continuous variables that did not match parametric criteria were compared by using Wilcoxon or Mann-Whitney U tests. Continuous variables are depicted as mean ± standard deviation (SD) or as median and interquartile range (IQR), according to their distribution. Categorical data are expressed as percentages. Next, we assessed the difference in those parameters between groups for both trial time periods independently (2009-2016, and 2017-2020). Statistical significance was defined as p-value ≤ 0.05. Analyses were performed via IBM SPSS software version 24.