Statistical analysis
Statistical analysis was performed with IBM SPSS Statistics 26 (IBM Corp., Armonk, NY). Normal distribution was formally tested with the Shapiro–Wilk test. Continuous data are presented as the mean with standard deviation. ANOVA was used to compare repeated measurement data at different time points, and a T test was used for comparisons between two groups. Categorical data are presented as frequencies and percentages. Categorical variables were compared using the chi-square test. The Pearson method was used to compare the correlation between the LUS score and PaO