Abstract
Malnutrition is associated with poor surgical outcomes, and therefore optimizing nutritional status preoperatively is very important. The purpose of this paper is to review the literature related to preoperative parenteral nutrition (PN) and to provide current evidence based guidance. A systemic online search of PubMed, Medline, and Cochrane Databases from January 1990 to February 2020 was done. Sixteen studies were included in this narrative review, including four meta-analyses and twelve clinical trials. The majority of studies have demonstrated benefits of preoperative PN on postoperative outcomes, including reduced postoperative complications (8/10 studies) and postoperative length of stay (3/4 studies). Preoperative PN is indicated in malnourished surgical patients who cannot achieve adequate nutrient intake by oral or enteral nutrition. It can be seen that most studies showing benefits of preoperative PN often included patients with upper gastrointestinal cancer and inflammatory bowel disease (10/12 studies), which gastrointestinal problems are commonly seen and enteral nutrition may be not feasible. When preoperative PN is indicated, adequate energy and protein should be provided, and patients should receive at least seven days of PN prior to surgery. The goal of preoperative PN is not weight regain, but rather repletion of energy, protein, micronutrients, and glycogen stores. Complications associated with preoperative PN are rarely seen in previous studies. In order to prevent and mitigate the potential complications such as refeeding syndrome, optimal monitoring and early management of micronutrient deficiencies is required.