Immunonutrition in High-risk Surgical Patients: a Systematic Review and Analysis of the Literature

Background: Immunomodulating diets (IMDs) have been demonstrated to improve immune function and modulate inflammation. However, the clinical benefit of these diets in patients undergoing elective surgery is controversial. The goal of this meta-analysis was to determine the impact of IMDs on the clinical outcomes of high-risk patients undergoing elective surgery.

Methods: The review included prospective, controlled, clinical trials that compared the clinical outcome of elective surgical patients who were randomized to receive an IMD or a control enteral diet. Studies were stratified according to the type of IMD and the timing of the initiation of the IMD. Data were abstracted on study design, study size, patient population, and IMD used. The outcomes of interest were the acquisition of new infections, wound complications, length of hospital stay (LOS), and mortality. Meta-analytic techniques were used to analyze the data.

Results: Twenty-one relevant studies were identified, which included a total of 1918 patients. Immunonutrition significantly reduced the risk of acquired infections, wound complications, and LOS. The mortality rate was 1% in both groups. The treatment effect was similar regardless of the timing of the commencement of the IMD. The benefits of immunonutrition required both arginine and fish oil.

Conclusions: An immunomodulating enteral diet containing increased amounts of both arginine and fish oil should be considered in all high-risk patients undergoing major surgery. Although the optimal timing cannot be determined from this study, it is suggested that immunonutrition be initiated preoperatively when feasible.