Perioperative nutrition and ERAS protocols: a systematic review of their impact on hospital stay, complications, infections, and immunometabolic outcomes in surgical patients

Perioperative nutrition is a crucial determinant of surgical outcomes, influencing immune function, wound healing, and recovery [1]. Malnutrition affects up to 50% of surgical patients and is associated with increased morbidity and prolonged hospital stays [2]. Enhanced recovery after surgery (ERAS) programs integrate evidence-based interventions, including optimized nutritional support, to mitigate surgical stress and enhance metabolic resilience [3]. Despite well-established guidelines, adherence to perioperative nutrition protocols remains inconsistent across clinical settings [4].

This systematic review evaluates the impact of ERAS protocols and perioperative nutritional interventions on clinical outcomes, including hospital length of stay, postoperative complications, infection rates, and metabolic and immune responses.

A comprehensive literature search was conducted in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar, including randomized controlled trials (RCTs) and prospective studies published between 2019 and 2024. Studies evaluating perioperative nutrition strategies—enteral, parenteral, and immunonutrition—in adult surgical patients were included [5]. Primary outcomes included hospital length of stay and postoperative complications, while secondary outcomes assessed infection rates, immune response, metabolic markers, morbidity, and mortality. Owing to marked variability in study designs, nutritional interventions, and outcome definitions, meta-analysis was not appropriate. Therefore, a qualitative synthesis was undertaken to accurately reflect the clinical complexity and ensure methodological rigor.

Twenty-eight studies met the inclusion criteria, encompassing 3385 patients across various surgical specialties. Implementation of ERAS protocols significantly reduced hospital stays, with reductions ranging from 12 to 40% [6], and decreased postoperative complications by 30–50% [7]. Immunonutrition and early enteral feeding were associated with lower infection rates [8] and improved immune and metabolic responses [9]. However, variability in adherence and institutional implementation affected outcome consistency [10].

The findings reinforce the role of perioperative nutrition and ERAS protocols in improving surgical outcomes, reducing complications, and enhancing recovery [11]. Standardized implementation and tailored nutritional strategies, particularly for high-risk populations, are essential for optimizing perioperative care [12]. Further large-scale trials are needed to refine the timing, composition, and patient selection criteria for perioperative nutrition within ERAS pathways [13].