Emergency laparotomies, which most often is performed due to high risk disease (bowel obstruction, ischemia, perforation, etc.), make up 11 % of surgical procedures in emergency surgical departments, however, give rise to 80 % of all postoperative complications. The 30-day mortality rates in relation to these emergent procedures have been reported between 14-30 %, with even higher numbers for frail and older patients. The specific reasons for these outcomes are not yet known, however, a combination of preexisting comorbidities, acute illness, sepsis, and the surgical stress response that arise during- and after the surgical procedure due to the activation of the immunological and humoral system, is most likely to blame. The complex endocrinological response and consequences of this response to emergency surgery are sparsely reported in the literature.

The aim of this PHASE project is to evaluate and describe the temporal endocrine, endothelial and immunological changes after major emergency abdominal surgery, and to associate these changes with clinical postoperative outcomes.

Inclusion Criteria:

• Surgery within 72 hours of an acute admission to the Department of Surgery or an acute reoperation.
• Major gastrointestinal surgery on the gastrointestinal tract (see intervention definition)

Exclusion Criteria:

• Not capable of giving informed consent after oral and written information
• Previously included in the trial
• Elective laparoscopy
• Diagnostic laparotomy/laparoscopy where no subsequent procedure is performed (NB, if no procedure is performed because of inoperable pathology, then include)
• Appendectomy +/- drainage or Cholecystectomy +/- drainage of localized collection unless the procedure is incidental to a non-elective procedure on the GI tract
• Non-elective hernia repair without bowel resection.
• Minor abdominal wound dehiscence unless this causes bowel complications requiring resection
• Ruptured ectopic pregnancy, or pelvic abscesses due to pelvic inflammatory disease
• Laparotomy/laparoscopy for pathology caused by blunt or penetrating trauma, esophageal pathology, pathology of the spleen, renal tract, kidneys, liver, gall bladder and biliary tree, pancreas or urinary tract

Patients ≥ 18 years old undergoing acute major gastrointestinal surgery within 72 hours of their admission to the Department of Surgery or an acute reoperation.

Major gastrointestinal surgery are defined as procedures involving the stomach, small or large bowel, or rectum for conditions such as perforation, ischaemia, abdominal abscess, bleeding or obstruction.

Patients will be consecutively screened for inclusion.