Sample size calculation and statistical analysis
hypotension
The sample size was calculated by PASS 15.0 software. According to our pre-experiment, the incidence of hypotension was found to be 18% in the RT group, 40% in the P group, and 25% in the R+P group, a sample size of 229 achieves 80% power to detect an effect size of 0.2051 using a 2 degrees of freedom Chi-Square Test with a significance level (alpha) of 0.05, and considering the loss rate of 20%, the final sample size should not be less than 287.Results were analyzed by SPSS 25.0, with quantitative data expressed as mean ± standard deviation and qualitative data expressed as number and frequency. For population baseline analysis, we used one-way analysis of variance (ANOVA) for quantitative data with normal distribution and homogeneous variance, and χA two-sided test was chosen for all analyses and was statistically significant at 