For a study, researchers sought to determine how newborns with very low birth weights (VLBW, <1500 g) responded to receiving more electrolytes through parenteral nutrition (PN).

All VLBW children born before (n = 81) and after (n = 53) the initiation of a concentrated PN regimen were included in the single-center cohort research. Clinical records were used to gather daily dietary intakes as well as plasma concentrations of calcium, potassium, phosphate, sodium, and chloride.

Newborns that received concentrated PN consumed more electrolytes during the first postnatal week than infants who received original PN. Hypokalemia (<3.5 mmol/L; 30% vs 76%, P<0.001) and severe hypophosphatemia (<1.0 mmol/L; 2.2% vs 17%, P=0.02) were less common in infants who received concentrated PN. While a phosphorus intake below the recommended level can explain the relatively high occurrence of severe hypophosphatemia in babies who had original PN, the potassium intake during the first three postnatal days (mean±SD: 0.7± 0.2 mmol/kg/d) was within the recommended range. The difference in salt consumption between the 2 groups had no impact on the prevalence of early hypernatremia.

During the first few days of life, a sodium-containing PN solution (approximately 2.7 mmol/100 mL) does not result in hypernatremia in VLBW newborns. Furthermore, to avoid early hypokalemia, it may be important to provide at least 1 mmol potassium/kg/d during the first 3 postnatal days.