Neonatal Therapeutic Hypothermia-Associated Hypomagnesemia During Parenteral Nutrition Therapy

Background: Hypoxic-ischemic encephalopathy (HIE) is a significant cause of morbidity and mortality in the neonatal population. Total body cooling in term infants who meet the criteria for moderate to severe HIE has been shown to be neuroprotective. A decreased core body temperature is known to affect kinetic properties of many enzyme systems in which magnesium is a cofactor. Maintenance of magnesium during therapeutic hypothermia appears to play an important role in neuroprotection. Currently, there are no studies evaluating the effects that therapeutic hypothermia in neonates has on serum magnesium levels and implications for parenteral nutrition (PN) management. Our hypothesis was that neonatal hypothermia would result in hypomagnesemia and require magnesium therapy. Methods: Laboratory measurement of serum magnesium was obtained in all infants during the cooling process. Results: Serum magnesium was depressed (<1.6 mg/dL) in 80% of the infants cooled despite administration of standard PN and required additional magnesium supplementation. Conclusion: Further studies are needed to determine the target magnesium required for PN in hypothermic therapy.