Background: Critically ill patients with acute kidney injury may require parenteral nutrition (PN) and continuous renal replacement therapy (CRRT). Introduction of a phosphate-free premixed renal replacement fluid without system-wide education in May 2011 resulted in increased incidence of hypophosphatemia, necessitating change in practice. Changes included (1) maximizing phosphate in PN, (2) modifying the CRRT order set, and (3) developing a CRRT competency evaluation for nutrition support team members. This study evaluates the effect of these changes on the incidence of hypophosphatemia. Methods: Phosphate levels and predicated probability of hypophosphatemia were evaluated for patients receiving PN and CRRT over 3 time periods: prior to implementing the changes (preimplementation), during change implementation (intermediate), and following implementation (postimplementation). Hypophosphatemia was defined as a serum phosphate level <2.5 mg/dL. Generalized linear mixed models were applied for statistical analysis. Results: The retrospective study includes 336 measures from 49 patients. Patients in the intermediate and postimplementation periods were not significantly different from each other and had significantly higher mean phosphate levels than patients in the preimplementation period (P < .0001). They were also less likely to develop hypophosphatemia compared with preimplementation patients (intermediate: odds ratio [OR], 0.07; 95% confidence interval [CI], 0.03–0.18, P < .0001; postimplementation: OR, 0.09; 95% CI, 0.03–0.27, P < .0001). Conclusions: Modifications in phosphate dosing together with CRRT education reduced the incidence of hypophosphatemia in PN patients receiving CRRT. Communication of significant changes in clinical care should be shared with all services prior to implementation. Communication and planning between services caring for complex patients are necessary to prevent systems-based problems.