Serum calcium concentrations and incidence of hypocalcemia in infants with moderate or severe hypoxic-ischemic encephalopathy: Effect of therapeutic hypothermia

Abstract

BackgroundHypocalcemia is a common morbidity in asphyxiated infants. Therapeutic hypothermia (TH), the standard of care for infants with moderate and severe hypoxic-ischemic encephalopathy (HIE), promotes neuroprotection by several mechanisms including a decrease in intracellular calcium (Ca2+) influx which may improve serum Ca2+ levels and homeostasis. AimsTo evaluate the impact of TH on Ca2+ homeostasis. Study designHistorical, retrospective cohort analysis. SubjectsInfants with moderate or severe HIE admitted to the hospital with≤24hours of age, gestational age≥36weeks, and birth weight ≥1800g, before (pre-TH) and after (post-TH) TH was implemented. Outcome measuresMinimum and maximum serum levels of ionized Ca2+ (iCa2+) and magnesium (Mg), Ca2+ and Mg intakes, and incidence of hypo/hypercalcemia during the first week of life. ResultsA total of 67 infants were included: 29 pre-TH and 38 post-TH. Minimum iCa2+levels were significantly lower in the pre-TH group; some infants required Ca2+ boluses infusions. In the post-TH group, a significantly lower intake of Ca2+ was necessary to maintain normal Ca2+ levels and no infant required boluses. The incidence of hypocalcemia was higher in the pre-TH group with a statistically significant difference on day 2 of life (18 vs 0%; p=0.01). ConclusionsAfter the implementation of TH, iCa2+ levels were within normal ranges despite lower Ca2+ intakes. A lower incidence of hypocalcemia was observed during cooling. Our findings support the hypothesis that TH improves Ca2+ homeostasis in HIE infants.