Recent advances in nutrition therapy of the patient undergoing elective surgery have focused on greater utilization of the gut, feeding closer to the time of surgery, avoiding extensive bowel preparations or use of nasogastric tubes and drains, and measures to promote and maintain intestinal motility. Failure to have protocols in place for delivery of enteral nutrition (EN) through the perioperative period should not lead to inappropriate use of parenteral nutrition (PN) as a default therapy, because in many circumstances, standard therapy with no specialized nutrition support may be associated with better outcome. The journal of parenteral and enteral nutrition says that in cases where EN is not feasible and the patient shows evidence of malnutrition, surgery should be delayed 7–10 days to provide perioperative parenteral nutrition. For patients requiring urgent surgery where EN is not feasible, the initiation of parenteral nutrition postoperatively should be delayed 5–7 days. Whether alternative sources for lipid emulsion and availability of parenteral immune-modulating agents in the future can improve the risk/benefit ratio of parenteral nutrition and expand its use through the perioperative period awaits further study.
Provision of EN when feasible is always the first choice for nutrition therapy for the elective surgery patient undergoing a large operative procedure. Protocols should be in place to optimize the enteral delivery of nutrients and promote intestinal tolerance and gut contractility. Plans should be made for placement of enteral access during surgery. Provision of parenteral nutrition and parenteral nutrition support is not the automatic default therapy in cases where enteral feeding is not feasible. Providing standard care with no specialized nutrition therapy is appropriate when EN is not feasible prior to surgery for a well-nourished patient or in the immediate postoperative period for any patient requiring urgent surgery. If a patient is malnourished based on low BMI or weight loss prior to admission, surgery should be delayed to initiate parenteral nutrition 5–7 days preoperatively and parenteral nutrition support should also be provided. Consideration should be given to withholding proinflammatory soy-based lipid emulsions to reduce the risk of postoperative complications. If no enteral access can be achieved at the time of surgery, the parenteral nutrition would be continued postoperatively 1 day after surgery. In the patient requiring urgent surgery when EN is not feasible, parenteral nutrition should not be initiated in the immediate postoperative period but should be delayed for 5–7 days. Initiate parenteral nutrition only if the duration of therapy is anticipated to be greater than 7 days, since any parenteral nutrition therapy less than 7 days would be expected to have no outcome benefit and may actually increase risk to the patient. For the patient receiving appropriate perioperative parenteral nutrition, the surgeon may consider stopping the parenteral nutrition 2–3 hours before surgery and restarting the morning after surgery. Due to the physiologic stress of a major operation, the journal of parenteral and enteral nutrition says that parenteral nutrition may be modified in the postoperative period to promote permissive underfeeding (providing 80% of caloric requirements).