Lipid Infusion Following Major Surgery

Surgery puts a lot of stress on the body, and during recovery from surgery, the body uses a lot of energy to help with healing and getting stronger. Often, sugars are given before surgery to help give the body an energy boost. Lipid solutions can also be used as an energy source and are commonly used as supplements in patients needing long-term nutrition from an intravenous route (e.g., total parenteral nutrition) when they can not eat by mouth for a medical reason. Intralipid, a solution of lipid molecules from soybeans and eggs, is commonly used for patients who need nutrition and energy supplements. The investigators wish to test whether giving Intralipid immediately after surgery can improve recovery from major surgery.

BACKGROUND The perioperative events associated with major surgery trigger the body's stress response, compromising optimal post-surgical recovery and outcomes. Moreover, traditional perioperative indications, such as restricting food up to two days before surgery, have been shown to be associated with poor outcomes following surgery. The Enhanced Recovery After Surgery (ERAS) protocol, initiated in the early 2000's, aimed to address these problems. The ERAS protocol has recommendations for pre-, intra-, and post-operative stages, with the goal of modifying physiological and psychological responses to surgery. A key component of ERAS is perioperative nutrition, including avoidance of fasting before surgery and carbohydrate loading up to two hours pre-surgery. It is hypothesized that adequate nutrition and provision of an energy source in the perioperative period can attenuate the body's stress response during surgery, thereby enabling faster and more successful recovery.

Early post-operative feeding is another recommendation of ERAS and is also intended to ensure optimal metabolic balance. Post-operative nutrition of ERAS patients generally involves oral feeding with energy-dense nutritional supplements in the days after surgery until the patient is ready for normal food intake. Lipids and carbohydrates form the bulk of these supplements, providing a readily available energy source. Lipid emulsions, such as Intralipid®, are used commonly in total parenteral nutrition and are also indicated as an energy source in patients for whom the usual intravenous fluid therapy would not be adequate. Lipid emulsions alone may therefore be helpful in enhancing recovery following major surgery, particularly in patients who are not good candidates for a strict ERAS protocol. With respect to short-term outcomes following surgery, Intralipid has been shown to modulate blood pressure by increasing systemic vascular resistance and cardiac output.

Only one study so far has evaluated post-surgery recovery outcomes following administration of lipid emulsion exclusively. The investigators found that patients receiving an intravenous infusion of lipid emulsion experienced better overall recovery and faster time eye opening and exit from the operating room compared to patients receiving an infusion of 0.9% normal saline. While these results suggest that post-operative lipid delivery improves recovery, the study did not assess differences in basic vital signs between the two groups, and the subjects were limited to those undergoing laparoscopic cholecystectomy. In this study, the investigators will recruit patients undergoing any surgery of the abdomen and assess post-operative outcomes, including vital signs, following an intravenous bolus of Intralipid® 20% or 0.9% normal saline.

OBJECTIVE To demonstrate that patients receiving an intravenous bolus of Intralipid® 20% immediately following surgery experience improved post-surgical recovery compared to patients receiving an intravenous saline bolus.

HYPOTHESIS The investigators hypothesize that patients who receive an intravenous bolus of Intralipid® following major abdominal surgery will show more stable vital signs and faster discharge from the recovery room compared to patients receiving a saline bolus.

Eligibility Criteria:
Inclusion Criteria:

* Adult patients (\>18 years old)
* Scheduled for abdominal surgery
* Provide written, informed consent

Exclusion Criteria:

* Patient refusal
* Pre-existing neurological deficit
* Existing or potential for coagulation abnormality
* Local or systemic infection
* Allergy to local anesthetic
* Contraindication to propofol
* Liver disease/compromised liver metabolism