2.4. Statistical Analysis
SE
The sample size was calculated using the PASS 2008 software (NCSS, Kaysville, UT, USA). A preliminary investigation showed that the incidence rates of PS in the PACU, as a primary outcome in groups S and R, were 50% and 14.3%, respectively. The results indicated that a sample size of 33 patients for each group would allow for the detection of a significant difference with a power of 90% and an α-coefficient of 0.05. Considering the dropout rate of 10%, the final sample size for each group was 37 patients. SPSS (version 25.0; SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Data are presented as mean (M) ± standard deviation (SD), estimated mean (M) ± standard error (SE), or number and percentage (%). For continuous variables, the groups were compared using Student’s 