Background: 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).
Methods: 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.
Results: 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.
Conclusion: Individualized phosphate replacement was effective and safe for both moderate and severe hypophosphatemia, but was more accurate in moderate hypophosphatemia.