REstrictive Versus LIbEral Fluid Therapy in Major Abdominal Surgery

Inclusion criteria

• adults (≥18 years) undergoing elective major surgery and providing informed consent
• all types of open or lap-assisted abdominal or pelvic surgery with an expected duration of at least 2 hours, and an expected hospital stay of at least 3 days (for example, oesophagectomy, gastrectomy, pancreatectomy, colectomy, aortic or aorto-femoral vascular surgery, nephrectomy, cystectomy, open prostatectomy, radical hysterectomy, and abdominal incisional hernia repair)
• at increased risk of postoperative complications, defined as at least one of the following criteria:
• age ≥70 years
• known or documented history of coronary artery disease
• known or documented history of heart failure
• diabetes currently treated with an oral hypoglycaemic agent and/or insulin
• preoperative serum creatinine >200 μmol/L (>2.8 mg/dl)
• morbid obesity (BMI ≥35 kg/m2)
• preoperative serum albumin <30 g/L
• anaerobic threshold (if done) <12 mL/kg/min
• or two or more of the following risk factors:
• ASA 3 or 4
• chronic respiratory disease
• obesity (BMI 30-35 kg/m2)
• aortic or peripheral vascular disease
• preoperative haemoglobin <100 g/L
• preoperative serum creatinine 150-199 μmol/L (>1.7 mg/dl)
• anaerobic threshold (if done) 12-14 mL/kg/min

Exclusion criteria

• urgent or time-critical surgery
• ASA physical status 5 - such patients are not expected to survive with or without surgery, and their underlying illness is expected to have an overwhelming effect on outcome (irrespective of fluid therapy)
• chronic renal failure requiring dialysis
• pulmonary or cardiac surgery - different pathophysiology, and thoracic surgery typically have strict fluid restrictions
• liver resection - most units have strict fluid/CVP limits in place and won't allow randomisation
• minor or intermediate surgery, such as laparoscopic cholecystectomy, transurethral resection of the prostate, inguinal hernia repair, splenectomy, closure of colostomy - each of these are typically "minor" surgery with minimal IV fluid requirements, generally low rates of complications and mostly very good survival.