Purpose: Electrolyte replacement aiming for potassium of 4, magnesium of 1 and phosphate of 1 is an internationally implemented optimisation strategy for surgical pathologies. However, replacement to ‘411’ incurs a supranormal goal, requiring time and resource investment, costing millions with substantial environmental detriment. Methodology: This systematic review aims to assess all current surgical electrolyte replacement evidence and rationale. Sub-questions include reviewing General Surgery pathologies, post-operative and surgical subspecialty use. Three databases; MEDLINE, Embase and Central, were searched from 2008-2023, with expanded and MeSH terms; surgery AND electrolyte OR potassium OR magnesium OR phosphate AND replace. Screening involved 2 reviewers, and a 3rd for inclusion/exclusion conflicts. Results: The review identified 9022 results. Title/abstract screening included 83 articles with 318 conflicts. The 3rd reviewer conflict resolution found 110 papers. Full text assessment is ongoing, initial findings demonstrates the majority of papers evaluate cardiothoracic patients and arrhythmia, 20 papers relate to general surgery, 15 are relevant for all specialties, few evaluate subspecialty implementation. Results widely vary demonstrating broad benefits or lack of measurable benefit in multiple contexts. Conclusion/s: After comprehensive systemic rapid review of >9000 articles, there is limited evidence for predominantly general surgical patient electrolyte replacement, with high outcome measure variability. This provides clinical and economic incentive for study design to assess whether replacement to ‘411’ is justified.