Abstract 1357

The use of magnesium sulfate for the prevention of seizures in preeclampsia has been found to result in neonatal hypermagnesemia, which has been associated with several clinical findings, including electrocardiographic abnormalities and respiratory depression. The objective of this study was to correlate serum magnesium levels with specific changes in cardiac rate and/or rhythm and respiratory abnormalities. We enrolled 23 term infants, consecutively admitted to our NICU, born to preeclamptic mothers who were treated with magnesium sulfate. The infants were placed on cardiorespiratory monitors with event recording capability upon study enrollment, and remained on the monitors until serum magnesium levels had normalized (≤ 2.8 mg/dl). The event recording limits were set up at 16 seconds for apnea and at 80 beats per minute for bradycardia greater than 5 seconds in duration. In addition, a twelve-lead electrocardiogram was recorded daily in each infant. Our population consisted of 15 males and 8 females with a mean gestational age of 40 ± 1.5 weeks and a mean birth weight of 3107 ± 544 grams. Initial mean serum magnesium level on admission to the NICU was 4.8 ± 1 mg/dl. Although six infants (26%) had documented central apnea greater than 16 seconds in duration, no prolonged apnea (≥ 20 seconds) or bradycardia was found. The electrocardiographic findings in relation to serum magnesium levels on admission and following normalization are summarized below: (Table) We conclude that hypermagnesemia does not appear to result in significant prolonged central apnea or bradycardia. Furthermore, electrocardiographic findings in hypermagnesemia appear to be normal.

Table 1 No caption available
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