Intravenous phosphate repletion regimen for critically ill patients with moderate hypophosphatemia.

OBJECTIVE: To document the safety and efficacy of an intravenous phosphate repletion regimen that is more aggressive than recommended by previously published guidelines, in intensive care unit (ICU) patients with hypophosphatemia.

DESIGN: Prospective evaluation of rapid, intravenous phosphate repletion in eligible patients.

SETTING: Surgical ICU in a teaching hospital.

PATIENTS: Patients with a serum phosphorus concentration of < 2 mg/dL (< 0.65 mmol/L) while in the ICU.

INTERVENTIONS: Enrolled patients received 15 mmol of sodium phosphate in 100 mL of 0.9% sodium chloride, infused intravenously over a period of 2 hrs. Patients with a serum potassium concentration of < 3.5 mmol/L received potassium phosphate, if no other potassium supplementation was ordered. The same dose could be repeated to a maximum of 45 mmol in a 24-hr period if either the 6-hr or follow-up (18- to 24-hr) postinfusion serum phosphorus remained < 2 mg/dL (< 0.65 mmol). Serum electrolytes, renal function, vital signs, and reflexes were closely monitored.

MEASUREMENTS AND MAIN RESULTS: Eleven patients enrolled had baseline serum phosphorus values of 1.6 to 1.9 mg/dL (0.51 to 0.61 mmol/L). The serum phosphorus value immediately postinfusion was 2.3 to 5.3 mg/dL (0.74 to 1.7 mmol/L). Only one patient had a 6-hr postinfusion serum phosphorus of < 2 mg/dL (< 0.65 mmol/L), requiring two additional doses. Two other patients each required a second dose. Serum phosphorus was corrected in other patients with a single dose. No significant changes were noted in serum calcium, magnesium, or potassium concentrations, urine output, vital signs, or reflexes throughout the repletion period.

CONCLUSIONS: All patients were successfully repleted using the described protocol without any significant adverse effects. This repletion regimen may have widespread applicability in the ICU setting.