This study aims to compare two different methods for guiding intravenous (IV) fluid therapy in patients during their first 6 hours in the ICU after major abdominal surgery. The goal is to determine which method leads to a more optimal and precise amount of fluid administration. The objective is to compare the total fluid volumes administered when guided by Cardiac Index versus Central Venous Pressure, as well as mortality, length of stay, relaparotomy and reintubation in order to identify the more precise fluid management strategy for postoperative ICU patients.
Adult patients aged 18 to 65 years.
Patients with a Body Mass Index (BMI) between 18 and 30 kg/m².
Patients undergoing elective major abdominal surgery with a planned postoperative admission to the ICU.
Patients with an American Society of Anesthesiologists (ASA) physical status classification of I to III.
Patients with pre-operative cardiovascular disorders (Coronary Artery Disease, or heart failure NYHA Class III and IV).
Patients with severe renal impairment (Chronic Kidney Disease Stage V) with or without hemodialysis and fluid restrictions.
Non-sinus cardiac rhythm.
Pregnancy.