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

BACKGROUND: Hypocalcemia 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 (Ca(2+)) influx which may improve serum Ca(2+) levels and homeostasis. AIMS: To evaluate the impact of TH on Ca(2+) homeostasis. STUDY DESIGN: Historical, retrospective cohort analysis. SUBJECTS: Infants 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 MEASURES: Minimum and maximum serum levels of ionized Ca(2+) (iCa(2+)) and magnesium (Mg), Ca(2+) and Mg intakes, and incidence of hypo/hypercalcemia during the first week of life. RESULTS: A total of 67 infants were included: 29 pre-TH and 38 post-TH. Minimum iCa(2+)levels were significantly lower in the pre-TH group; some infants required Ca(2+) boluses infusions. In the post-TH group, a significantly lower intake of Ca(2+) was necessary to maintain normal Ca(2+) 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). CONCLUSIONS: After the implementation of TH, iCa(2+) levels were within normal ranges despite lower Ca(2+) intakes. A lower incidence of hypocalcemia was observed during cooling. Our findings support the hypothesis that TH improves Ca(2+) homeostasis in HIE infants.

The effect of the implementation of therapeutic hypothermia on fluid balance and incidence of hyponatremia in neonates with moderate or severe hypoxic-ischaemic encephalopathy.

AIM: To investigate the effect of the therapeutic hypothermia (TH), used in infants with moderate or severe hypoxic-ischaemic encephalopathy (HIE), on fluid balance and incidence of hyponatremia. METHODS: Retrospective cohort study of moderate and severe HIE infants before (pre) and after (post) TH implementation. Daily fluid and electrolytes intake/output were collected from the medical records of each patient from day 1 to day 4 of life. Hyponatremia was defined as sodium <130 mEq/L. RESULTS: A total of 67 infants were studied: pre-TH = 29 and post-TH = 38. Infants in the post-TH group had greater weight gain [140 g (62, 227) vs. 10 g (-100, 105) p < 0.001] and lower serum sodium (130.9 ± 4.5 mmol/L vs. 133.4 ± 5.7, p = 0.008). The incidence of hyponatremia increased from 48 to 76% (p = 0.02). CONCLUSION: In our centre, the implementation of TH was followed by an increased fluid retention and higher incidence of hyponatremia. Centres adopting TH should have clear guidelines for fluid and electrolyte management.