Phosphate Replacement in Critically Ill Patients with Hypophosphatemia

Abstract

Introduction: Hypophosphatemia occurs in 30–50% of ICU patients and is associated with respiratory failure and weaning difficulties. Optimal replacement protocols remain controversial. This review evaluates safety and efficacy.
Methods: Literature search (2010–2024) for RCTs and cohort studies on intravenous phosphate replacement in adults with moderate (<2 mg/dL) or severe (<1.5 mg/dL) hypophosphatemia. Primary outcomes: normalization rate, hypocalcemia, and acute kidney injury (AKI).
Results: Eight studies (n=1,205) reported that weight-based protocols (0.3–0.6 mmol/kg) normalized phosphate in 24 hours in 78% vs. fixed-dose (15 mmol) in 45%. Hypocalcemia (ionized calcium <1.1 mmol/L) occurred in 15% of rapid infusion (<4 hours) vs. 6% of slow (8–12h). No AKI difference.
Discussion: Weight-based dosing and slower infusion rates balance efficacy with hypocalcemia risk. Phosphate-calcium product precipitation is theoretical but rare with controlled rates.
Conclusions: Moderate-severe ICU hypophosphatemia should be corrected with weight-based intravenous phosphate given over ≥6 hours, with calcium monitoring.