Efficacy and safety of a phosphate replacement strategy for severe hypophosphatemia in the ICU

Experience with individualized phosphate replacement is limited in patients with severe hypophosphatemia. This study compares the efficacy and safety of an individualized regimen of serum phosphate < 0.4 mmol/l treatment in ICU patients to patients with moderate hypophosphatemia (0.4-0.6 mmol/l).

This retrospective cohort study included 36 patients with severe and 35 patients with moderate hypophosphatemia. Supplementation dose was calculated according to the equation: phosphate dose (in mmol) = 0.5 x body weight x (1.25 - [serum phosphate]). Sodium-potassium-phosphate was infused at a rate of 10 mmol/hour. Blood samples were taken at baseline and the next morning at 06.00 hrs.

Serum phosphate rose to a level > 0.40 mmol/l in all patients with severe hypophosphatemia. Serum phosphate increased to > 0.60 mmol/l in 56% of patients with severe hypophosphatemia and in 86% of patients with moderate hypophosphatemia (p = 0.01). Mild hyperphosphatemia was observed in one patient only (1.53 mmol/l), hyperkalemia was observed in three patients (all three had severe hypophosphatemia, average potassium after supplementation was 5.2 ±; 0.2 mmol/l) and serum calcium levels remained unchanged in both groups.

Individualized phosphate replacement was effective and safe for both moderate and severe hypophosphatemia, but was more accurate in moderate hypophosphatemia.