High protein intake can lead to serious hypophosphatemia and hypokalemia in growth restricted preterm newborns.

Abstract

High protein parenteral nutrition (HPPN) in the early postnatal period is a recommended strategy for very low birth weight (VLBW) infants. However, limited data is available on electrolyte changes when HPPN strategy is utilized. We investigated the impact of HPPN on the development of hypophosphatemia and hypokalemia in preterm VLBW newborns. A retrospective, single-center study investigated the levels of phosphate and potassium in VLBW infants who received HPPN (amino acids intake up to 3.5 g/kg/day) during the first week of life. Preterm infants were divided into two subgroups: appropriate for gestational age (AGA) and small for gestational age (SGA) newborns. Clinical data were obtained from hospital database and medical records. Overall, 170 VLBW infants were included for the study analysis: 41 SGA (mean birth weight 752 ± 39 g) and 129 AGA infants (mean birth weight 994 ± 23 g). Phosphate and potassium levels were significantly lower in the SGA infants compared to AGA infants (Phosphate: 0.97 ± 0.07 mmol/l vs. 1.44 ± 0.04 mmol/l, p < 0.001; Potassium: 3.0 ± 0.1 mmol/l vs. 3.6 ± 0.1 mmol/l, p < 0.001). Repeated measurement of serum phosphate and potassium is recommended when HPPN strategy is utilized in preterm SGA infants where significant hypophosphatemia and hypokalemia might have serious clinical consequences.