The study will have a pre-, intra and postoperative phase in which several demographic and clinical variables will be assessed. The samples for the immunophenotypic analysis will be drawn directly after induction of anesthesia and at various time points after end of surgery. The diagnosis of SIRS will be made during routine clinical visits on the first seven postoperative days using the Sepsis-related Organ Failure Assessment score (SOFA-score). The patients will be followed up for 30 days.