2.9 | Statistical analysis
Continuous data with a normal distribution are presented as mean ± standard error of the mean (SEM). Ranked data or data that failed to follow a normal distribution are presented as medians with interquartile range. For within-group comparison, a paired Student t-test was used to compare cardiopulmonary data between preinjury and immediately post injury. For between-group comparison, one-way analysis of variance followed by post hoc Student–Newman–Keuls test was performed for the comparison continuous variables, and the Kruskal–Wallis test followed by pairwise comparison was conducted for the comparison of lung injury scores among the five study groups. Statistical significance was defined as p value less than 0.05. Two-tailed p values of less than 0.05 were considered statistically significant for all analyses. All data management and analyses were performed using Statistical Package for Social Science version 22 (SPSS Inc., Chicago, IL, USA).