Individualized Perioperative Hemodynamic Goal-directed Therapy in Major Abdominal Surgery (iPEGASUS-trial)

Inclusion Criteria: * To provide high generalizability and representativeness the high number of patients with laparotomy and major surgical trauma is included into this study. - Therefore, open visceral, urological, and gynecological surgery is covered by this study. * Expected duration of surgery must be ≥ 120 minutes and requirement of volume therapy needs to be expected ≥ 2 liters. * Risk for any postoperative complications needs to be ≥10% assessed by the ACS (American College of Surgery)- NSQUIP (National Surgical Quality Improvement Program) risk calculator. Exclusion Criteria: * Patients \<18 years, * laparoscopic approach, * patients not having sinus rhythm, * patients having highly impaired left ventricular function (ejection fraction \<30%) or severe aortic valve stenosis (aortic valve area \<1 cm2, mean gradient \>40 mmHg), * pregnant women, * emergency surgeries (surgery required within 24 hours), * primarily vascular surgery, * patients suffering from septic shock, * patients having phaeochromocytoma, * patients suffering from non-cardiac chest pain, * refusal of consent, * patients receiving palliative treatment only (likely to die within 6 months) and patients suffering from acute myocardial ischemia (within 30 days before randomization) are excluded from the study. * Further, in case that clinicians intended to use cardiac output monitoring for clinical reasons patients should also not be included in the study.