This study is investigating the effect of intraoperative Noradrenaline on cardiac preload and stroke volume, after initial fluid resuscitation, in order to assess whether there is a masked preload responsiveness and ultimately whether the correction of this potential preload-responsiveness with fluid therapy will translate into increased tissue perfusion in emergency laparotomy.

Early detection and treatment of insufficient tissue perfusion and oxygenation is the main purpose of perioperative haemodynamic monitoring and management. Hypovolemia, septicaemia, and low flow states affecting central and peripheral perfusion are frequent in patients undergoing emergency laparotomy.

This study aims to assess the effects of Noradrenaline (NA) on cardiac preload, and tissue perfusion in patients undergoing emergency laparotomy, to investigate potential macro/microcirculatory uncoupling.

A single-centre, prospective interventional non-blinded single-arm study at the Department of Anaesthesiology and Intensive care Unit, Copenhagen University Hospital Hvidovre, Denmark. We will include patients undergoing emergency laparotomy. The study start is January 2021. After informed consent, patients will be included if they have an intraoperative need for Noradrenaline infusion >0.1 mcg/kg/min to maintain MAP ≥65 mmHg after resuscitation with a goal-directed fluid therapy algorithm. 20 patients will be included.

Intervention: At a steady state (MAP ≥65 mmHg) during the surgical procedure, we will reduce NA to investigate whether patients will be preload responsive while maintaining MAP > 50 mmHg and limiting stroke volume reduction to no more than 30%. After a subsequent fluid challenge, we will increase the dose of NA to re-establish a MAP ≥65 mmHg. In addition, peripheral and central perfusion indices, including gut perfusion, will be measured.

Inclusion Criteria:

1. Adults (18 years or over) undergoing emergency laparotomy/laparoscopy for following abdominal pathology:

   1. Perforated viscus
   2. Intestinal obstruction

2. Emergency re-operations after elective surgery owing to paralytic/obstructive ileus, anastomotic leakage

3. Provided verbal and written informed consent

4. Must speak and understand the Danish language

5. Intraoperative indication for Norepinephrine infusion

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. Reoperation owing to fascial separation with no other abdominal pathology identified and sub-acute colorectal cancer-surgery will be excluded from the cohort. Sub-acute surgery is defined as surgery planned within 48 hours.
3. Intestinal Ischemia
4. intraabdominal bleeding
5. Traumas, gynecological, urogenital and other vascular pathology, pregnant patients.
6. Dementia and/or cognitive dysfunction (diagnosed). If the patient is not awake, alert, and oriented, times three (to person, place, and time), this also qualifies as an exclusion criterion.

This study will include patients undergoing emergency laparotomy on suspicion of abdominal pathology, in need of intraoperative Noradrenaline infusion to maintain predefined normotension.