2.8. Statistics
ICCA
Metric data were tested for normal distribution using Kolmogorov–Smirnov tests and reported as the mean ± standard deviation in case of normal distribution; otherwise, the median and interquartile range (IQR) were reported. In the case of normal distribution, groups were tested using a two-tailed independent paired or unpaired t-test; in the case of non-normally distributed variables, a Mann–Whitney U test was used. Categorical variables were expressed as the number and percent and analyzed using the chi-square test. For numbers of cases less than five per group, a Fisher’s test was used. Demographic and intraoperative data were extracted via the reporting system of Philips IntelliSpace and Critical Care and Anesthesia (ICCA, Philips Medical Systems, Andover, MA, USA). For each patient, a full dataset was generated via the SQL-database in the environment of Microsoft SQL Server Management Studio (version 18.7.1, Washington, DC, USA). qPCR assays were evaluated using the delta-CT method [