IL2 and atrial fibrillation: Subjects with higher preoperativeand postoperative cortisol level remained at increased risk of developing delirium aftercontrolling for the following variables significant in univariable analysis: age,gender, cognitive performance (MoCA and TMT-B scores), preoperative urea, creatinine,hemoglobin concentration, peripheral vascular disease, duration of surgery, dose ofmidazolam, intraoperative hemoglobin level, partial pressure of oxygen, partial pressureof carbon dioxide, atrial fibrillation, and IL-2 concentration.