Statistical analysis
This pilot study with no sample size estimation conducted was expected to provide data to calculate sample size for further larger sample-sized trials. Normally distributed variables were reported as mean (standard deviation) and analyzed using the Student’s t test, non-normally distributed variables were reported as median (interquartile range) and analyzed using the Mann–Whitney U test, and categorical variables were reported as number (%) and analyzed using the Chi-square test or the Fisher's exact test. We used Kaplan–Meier plot to present the duration of mechanical ventilation from enrollment to 7 days. Statistical analysis was performed using SPSS 26.0 software (IBM SPSS Statistics, Armonk, NY) and GraphPad Prism 8.2.1 (GraphPad Software, San Diego, CA, USA). A 