2.7. Statistical Analyses
This was an explorative study and as such, no sample size calculation was performed. Patients undergoing RIPC, as described in the protocol, and having one preoperative blood sample and at least one postoperative blood sample withdrawn were included for analyses in this study. Categorical data are expressed as units (n, %) and compared between control patients and patients undergoing RIPC by Pearson’s Chi-squared test or Fisher’s Exact Test. Continuous data were visualised by histograms and quantile–quantile plots of residuals to control the data distribution and equality of variances. Parametric data were compared by Student’s To analyse changes in outcomes over time with repeated measurements, we applied a constrained linear mixed model (using the ‘LMMstar’ package (version 0.7.6) in R [We did a post-hoc power analysis applying the observed group difference and variance in the measurements of our primary outcome, RHI. Based on these estimates, our study had a power of 0.53, and to reach a power of 0.80, a sample size of 57 patients in each group would be necessary. All statistical analyses were performed using RStudio (RStudio Team (2019) [