Improvement of Fluid Balance in Patients Undergoing Surgery of the Colon and Rectum (HOC)

• L-FABP [ Time Frame: Every 30 minutes intraoperatively; every 60 minutes during the first 10 hours postoperatively; daily during 5 days postoperatively. ] [ Designated as safety issue: No ]
  Liver-Fatty Acid Binding Protein (another, but less specific marker of intestinal damage) is measured in plasma.
• CO2 gap [ Time Frame: Every 15 minutes intraoperatively; every 60 minutes in the first 10 hours postoperatively. ] [ Designated as safety issue: No ]
  The CO2 gap (difference arterial pCO2 and pCO2 of the stomach lumen) reflects global intestinal perfusion status and is measured every 15 minutes intraoperatively and every 60 minutes during the first 10 hours postoperatively.

58 patients undergoing surgery of the large bowel are divided into two groups. The control group will receive standard care. The intervention group will receive standard care plus optimization of the blood circulation based on in- or decrease of the output of the heart. Between group differences are measured primarily by markers of intestinal damage in plasma and urine. Also CO2 pressure in the stomach lumen is measured (reflecting blood supply to the gut).

The investigators hypothesize that the intervention group will have less intestinal damage, improved blood supply to the bowel and improved recovery of the operation compared to the control group.

• Procedure: Goal-directed fluid optimization
  Fluid administration and optimization based on cardiac output findings during surgery and during the first 8 hours of the postoperative phase.
• Other: Control group.
  Fluid regimen based on expertise anaesthesist.

• Experimental: Group 2
  Fluid administration and optimization based on cardiac output findings during surgery and during the first 8 hours of the postoperative phase.
  Intervention: Procedure: Goal-directed fluid optimization
• Group 1
  Fluid regimen based on expertise anaesthesist.
  Intervention: Other: Control group.

Inclusion Criteria:

• All patients undergoing elective colorectal surgery with anastomosis;
• Minimum age 18 years;
• Giving informed consent.

Exclusion Criteria:

• Other causes of intestinal damage: eg. IBD, occlusive disease;
• Steroid use;
• Esophageal varices and other esophageal disease;
• Aortic valve disease.