The Effect of Perioperative Cardiac Output-guided GDT on Oxygen Delivery, Consumption, and Microcirculatory Perfusion

Perioperative cardiac output-guided goal-directed therapy (GDT) triggers fluid, vasopressor, and inotrope administration assuming that optimizing cardiac output (i.e., global blood flow) ensures adequate oxygen delivery and microcirculatory perfusion - that are usually not directly monitored during goal-directed therapy. There is increasing evidence that perioperative cardiac output-guided goal-directed therapy may reduce postoperative complications compared to routine hemodynamic management in high-risk patients having major surgery. The effect of cardiac output-guided goal-directed therapy algorithms on perioperative oxygen delivery and consumption as well as microcirculatory perfusion, however, is unknown.

The investigators aim to investigate the effect of using different cardiac output-guided goal-directed therapy algorithms on perioperative oxygen delivery and consumption as well as sublingual microcirculatory perfusion compared to routine perioperative hemodynamic management in patients having major abdominal surgery with general anesthesia.

Perioperative cardiac output-guided goal-directed therapy (GDT) triggers fluid, vasopressor, and inotrope administration assuming that optimizing cardiac output (i.e., global blood flow) ensures adequate oxygen delivery and microcirculatory perfusion - that are usually not directly monitored during goal-directed therapy. There is increasing evidence that perioperative cardiac output-guided goal-directed therapy may reduce postoperative complications compared to routine hemodynamic management in high-risk patients having major surgery. The effect of cardiac output-guided goal-directed therapy algorithms on perioperative oxygen delivery and consumption as well as microcirculatory perfusion, however, is unknown.

With technological advancements a distinct monitoring of oxygen delivery and consumption as well as microcirculatory perfusion in the perioperative period has become possible. Using new technologies, a detailed understanding of the effect of cardiac output-guided goal-directed therapy on perioperative oxygen delivery and consumption as well as microcirculatory perfusion is of vital importance to further develop and improve perioperative hemodynamic treatment strategies.

In this pilot randomized-controlled trial, the investigators therefore aim to investigate the effect of using different cardiac output-guided goal-directed therapy algorithms on perioperative oxygen delivery and consumption as well as sublingual microcirculatory perfusion compared to routine perioperative hemodynamic management in patients having major abdominal surgery with general anesthesia.

Eligibility Criteria:
Inclusion Criteria:

* Adult patients (≥18 years) having elective major abdominal surgery with general anesthesia
* Expected duration of surgery at least 120 minutes
* Planned postoperative monitoring in intensive care unit

Exclusion Criteria:

* Emergency surgery
* Age \<18 years
* Body weight \<50 kg
* Pregnancy
* Atrial fibrillation
* Planned patient positioning in other position than supine position
* Surgery within the last 30 days
* Inaccessibility of the head during surgery
* Peripheral artery disease stage ≥IIb
* Chronic vasculitis
* Supraglottic airway management
* Enterostomy repair surgery