Hypernatremia causes brain shrinkage and resultant vascular rupture with cerebral bleeding and intraventricular hemorrhage (IVH). However, it is not known if rapid fluctuation in serum sodium in hypernatremic preterm infants results in IVH or death. The purpose of the study was to determine if the rapid rise in serum sodium or rapid correction of hypernatremia predict the composite outcome of severe IVH (grade 3 and 4) or death during the first 10 days of life.
Single center retrospective review of 167 preterm infants with a GA ≤26 weeks (admitted over a y-year period) who had serum sodium monitored at least every 12-24 hours and more frequently if indicated during the first 7-10 days of life. Logistic regression analysis identified which of the commonly cited risk factors of IVH (birth weight, gestation, gender, mode of delivery, multiple gestation, maternal chorioamnionitis, receipt of prenatal steroid, receipt of magnesium sulfate, pregnancy induced hypertension, Apgar score, receipt of delivery room epinephrine or chest compression, high frequency ventilation, pneumothorax, early onset culture-proven sepsis, PDA on echocardiography, hypotension requiring inotropes, changes in pH and PCO2, hyperglycemia needing insulin), including rapid (>10 and >15 mmol/l/day) rise or fall in serum sodium could predict the composite primary outcome in hypernatremic infants.
Ninety-eight (59%) of 167 infants studied developed hypernatraemia (serum sodium>150 mmol/L), with a maximum median serum sodium of 154 mmol/l (range 150-181, IQR 152-157), occurring on median postnatal age of 4 days (IQR 3-5). Grade 4 IVH was more frequent in infants with hypernatremia (hypernatremic group 17 of 98, 17% vs non-hypernatremic group 4 of 69, 6%; p=0.032, OR 3.4, 95% CI 1.1- 10.6). Among infants with hypernatremia, severe IVH or death occurred in 33 and 21 infants with rapid (>10 mmol/l/day) rise and drop in serum sodium, respectively. However, multivariate regression analysis identified early onset sepsis (p=0.017, OR 3.4, 95% CI 1.2- 9.2) and male gender (p=0.002, OR 6.5, 95% CI 1.9- 21.8) but not the rapid (>10 and >15 mmol/l/day) rise or fall in serum sodium to be independently associated with the composite outcome in hypernatremic infants.
Correction of hypernatremia not exceeding 10 to 15 mmol/l/day in hypernatremic preterm infants seems safe and was not associated with severe IVH or death during the first 10 days of life.