Component-Level Effects of Enhanced Recovery After Surgery Protocols on Postoperative Outcomes Across Surgical Specialties: A Systematic Review.

Enhanced recovery after surgery (ERAS) protocols have been widely adopted across surgical specialties to improve postoperative outcomes; however, the relative contribution of individual components within these multimodal pathways remains unclear. This systematic review aimed to evaluate the association between specific ERAS components and postoperative outcomes across diverse surgical settings. A comprehensive literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science for studies published between January 1, 2015, and December 31, 2025, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Observational cohort studies assessing ERAS protocols with reported compliance or component-level data and relevant postoperative outcomes were included. Data extraction focused on study characteristics, ERAS components, compliance measures, and clinical outcomes, and risk of bias was assessed using the Newcastle-Ottawa Scale. Eight studies comprising 4,959 patients across colorectal, hepatobiliary, pancreatic, thoracic, gynecologic, gastric, and head and neck surgeries were included. Higher ERAS compliance was consistently associated with reduced postoperative complications and shorter length of stay, demonstrating a dose-response relationship in most studies. Component-level analyses identified early mobilization, early enteral nutrition, perioperative fluid optimization, minimization of invasive tubes and catheters, and multimodal analgesia as the most consistently beneficial interventions. The timing of implementation, particularly within the early postoperative period, emerged as a critical determinant of outcomes. However, heterogeneity across studies and findings from a large multicenter cohort suggest that partial or inconsistent ERAS implementation may not confer significant benefit. Overall, while adherence to ERAS protocols is associated with improved postoperative recovery, a subset of key components appears to drive these effects across surgical specialties. These findings support a targeted, component-focused approach to ERAS implementation, emphasizing early postoperative interventions and high-fidelity execution, particularly in settings where full protocol adherence may be challenging.