Pathophysiology of perioperative fluid management in patients undergoing 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.

Inclusion Criteria:

1. Adults (18 years or over) undergoing emergency high-risk abdominal surgery for following abdominal pathology:

   1. Perforated small intestine
   2. Perforated large intestine
   3. Perforated ulcer
   4. Intestinal obstruction
   5. Anastomotic leakage following elective surgery

2. Provided verbal and written informed consent

3. Must speak and understand the Danish language

Exclusion Criteria:

1. Appendectomies, cholecystectomies, negative diagnostic laparoscopies/laparotomies, herniotomies without bowel resections, sub-acute internal hernias after gastric bypass surgery, sub-acute surgery for inflammatory bowel diseases.
2. Primary surgery for intestinal ischemia, abdominal bleed
3. Emergency re-operations after elective surgery owing to intraabdominal bleeding, paralytic/obstructive ileus, intestinal ischemia
4. Reoperation owing to fascial separation with no other abdominal pathology identified and sub-acute colorectal cancer-surgery were excluded from the cohort. Sub-acute surgery was defined as surgery planned within 48 hours.
5. Traumas, gynecological, urogenital and other vascular pathology, pregnant patients.
6. Dementia and/or cognitive dysfunction (diagnosed).

Adults (18 years or over) undergoing emergency high-risk abdominal surgery on suspicion of intestinal perforation (incl. ulcer), obstruction, anastomotic leak.