Perioperative nutrition therapy in high-risk patients: A narrative review.

Enhanced Recovery After Surgery (ERAS), as the plan A and standard for perioperative management, has shifted the focus from routine nutritional support toward the early identification and targeted management of high-risk patients. The new ICD-11 code for undernutrition offers an opportunity to better identify and characterize surgical patients at nutritional risk, while also potentially improving clinical recognition, acceptance of nutritional risk as a relevant perioperative condition, and reimbursement for targeted nutritional interventions. Early preoperative interventions should be considered. While short-term nutritional conditioning over 10-14 days primarily aims to correct nutritional and metabolic deficits, multimodal prehabilitation ideally requires 3-6 weeks to achieve meaningful improvements in physical fitness, functional capacity, and physiological reserve, particularly in patients undergoing major surgery after neoadjuvant therapy. Perioperative targeted strategies include carbohydrate loading (CHO drinks), immunomodulation, omega-3-fatty acids, hydroxymethylbutyrate, and probiotics or synbiotics. While parenteral nutrition is generally not required in low-risk patients with an uncomplicated recovery, the indication for supplemental (peripheral) parenteral nutrition should not be missed in high-risk patients with inadequate oral or enteral intake. Structured postoperative, post-discharge nutritional monitoring and rehabilitation should be integrated more consistently, especially in patients with eventful and complicated clinical courses.