Pathophysiology of Perioperative Fluid Management in Emergency Laparotomy

In critically ill patients and patients undergoing major surgery, the combination of internal fluid shifts and fluid retention resulting in extravascular fluid accumulation and postoperative organ dysfunctions, complicates perioperative fluid management and influences patient outcome. Changes in extravascular volume after surgery have been much debated, studies in major surgery suggest that extracellular volume expansion may correlate with intraoperative fluid administration, while other studies show the intravascular volume to be decreased after surgery. Difficulty in obtaining accurate measurements of the fluid phases is recognized and despite years of research, perioperative extravascular volume changes have not been clarified in acute high-risk abdominal (AHA) surgery. It is essential to be able to identify and characterize the transition from necessary fluid resuscitation to harmful fluid volume accumulation, intra- as well as extravascular. The present study seeks to investigate the perioperative fluid status and fluid shifts in patients undergoing AHA surgery, specifically focusing on intra- versus extra-vascular fluid status in patients with intestinal obstruction versus intestinal perforation.