REstrictive Versus LIbEral Fluid Therapy in Major Abdominal Surgery

Physicians differ in their approaches to surgical fluid therapy, with some preferring higher volumes and others lower volumes. Each approach has potential advantages and disadvantages. Currently, there is no compelling evidence that one approach is better than the other. This study tests whether giving a volume on the low end of the usual amount ("restrictive management") has a different rate of complications compared to a volume on the high end of the usual amount ("liberal management"). This study will compare liberal and restrictive fluid management to determine their effects on major complications after abdominal surgery.

Those who take part in the study will be visited five times before and after surgery in the hospital. Once discharged from the hospital, participants will be called 4 times on the telephone.

Preadmission Clinic/Preoperative Visit

* Sign the consent document
* Have blood drawn for standard preoperative tests (standard of care)
* Have an electrocardiogram (standard of care)
* Complete a questionnaire on disability (research)

Day of Surgery

* Have blood drawn if not already done during the first visit (standard of care)
* Have an electrocardiogram if not already done during the first visit (standard of care)
* Be randomly assigned to either restrictive or liberal fluid management (research)

Post-op Day 1

* Have an electrocardiogram done (research)
* Have blood drawn for standard tests (standard of care)
* Have a wound inspection, if there is a change of dressing (standard of care)
* Complete a questionnaire about your recovery (research)

Post-op Day 3

* Have blood drawn for standard tests (standard of care) and c-reactive protein, which can indicate infection (for research).
* Have a wound inspection, if there is a change of dressing (standard of care)
* Complete a questionnaire about your recovery (research)

Day of Discharge

* Have a wound inspection, if there is a change of dressing (standard of care)

  30-Day Follow-up Phone Call
* Complete a questionnaire about your recovery (research)
* Complete a questionnaire about disability (research)

  3 Month, 6-Month, and 12-Month Follow-up Phone Calls
* Complete a questionnaire about disability (research)


Eligibility Criteria:
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.