Study sample size and statistical analysis
atelectasis
ATELECTASIS
Our sample size was calculated using data obtained from pre-test results, the incidence of atelectasis in the spontaneous breathing group was approximately 90% and in the mechanical ventilation group was 40%. The sample size was calculated using G Power software, the require sample size was at least 22 patients in each group, with a set α error of 0.05, a power of 0.9. And a 10% loss to follow-up was also considered. Therefore, we enrolled 23 patients in each group.SPSS 23.0 software was used for analysis. Normally distributed measurement data were expressed as mean ± standard deviation and a t-test for independent samples was used for comparison between groups. Skewed distribution data were expressed as median (quartile [full range]) and a non-parametric test was used for comparison between groups. Quantitative data were compared using the 