Phosphate Derangements in Critical Care: Mechanisms, Manifestations and Management

Abstract Phosphate plays a fundamental role in numerous physiological processes essential for cellular function, including energy metabolism, cell signaling, and acid–base balance. In critical care settings, disturbances in phosphate homeostasis are common yet frequently overlooked. This narrative review examines the current understanding of phosphate metabolism in critically ill patients, synthesizing evidence from published observational studies, limited randomized controlled trials, and clinical practice guidelines. Hypophosphatemia occurs in 20%–80% of intensive care unit (ICU) patients depending on the population studied, and observational data suggest associations with increased morbidity and mortality, particularly in patients requiring mechanical ventilation, those with sepsis, and individuals receiving renal replacement therapy. While refeeding syndrome remains the most recognized cause of acute hypophosphatemia, multiple factors contribute to phosphate derangements in critical illnesses. This review discusses diagnostic approaches, clinical manifestations, and evidence-based management strategies for phosphate abnormalities in the ICU. We critically appraise available evidence regarding phosphate replacement protocols and their impact on patient outcomes. Additionally, the review explores the potential role of phosphate as a prognostic biomarker in critical illness. Recent advances in machine learning approaches and systematic reviews have enhanced our understanding of phosphate disorders, though significant knowledge gaps persist. Finally, we identify research priorities and suggest directions for future investigation to optimize phosphate management in critically ill patients.