Sources of unintentional manganese delivery in neonatal parenteral nutrition.

Abstract

Manganese (Mn) neurotoxicity is a concern in neonates receiving parenteral nutrition (PN). Prior studies have identified Mn contamination of PN ingredients as a source of daily Mn exposure from PN. This study was conducted to determine which neonatal PN ingredients are sources of this unintentional Mn delivery. Mn concentration was measured in different lot numbers of individual PN ingredients using inductively coupled plasma-mass spectrometry. PN admixtures were then prepared using standard doses of the tested individual ingredients, and admixture Mn concentration was measured. Magnesium sulfate and calcium gluconate are the major contributors to hidden unintentional Mn exposure in neonatal PN. Maximum measured Mn concentrations in these two ingredients were 443 and 46.8 mcg/L, respectively. Sodium phosphate and potassium phosphate were the next highest at 40 and 24 mcg/L, respectively. Other ingredients contained a trivial or no measurable quantity of Mn. PN admixture Mn content was 16%-30% higher than predicted values based on individual ingredient Mn content. If infused at 150 ml/kg/day, a standard neonatal PN admixture with no added Mn is capable of unintentionally delivering up to 0.9 mcg/kg/day Mn. Neonatal PN without any added Mn provides close to the American Society for Parenteral and Enteral Nutrition (ASPEN)-recommended Mn dosage of 1 mcg/kg/day. This supports the potential utility of a Mn-omission approach to trace element provision in neonatal PN. Further studies are needed to test such an approach and to evaluate the clinical significance of unintended Mn delivery in neonates receiving PN.