Intracranial hemorrhage following intravenous administration of sodium bicarbonate or saline solution in the newborn lamb asphyxiated in utero

Abstract

The effects of intravenously administered sodium bicarbonate were studied in near-term neonatal lambs asphyxiated in utero by maternal hypotension. Following tracheal intubation and manual ventilation with 100 per cent oxygen, the extracellular base deficits of ten neonates were corrected with sodium bicarbonate, 4.2 per cent, in 5 per cent dextrose (964 mOsm/l). Nine neonates alternatively received an isovolumic infusion of physiologic saline solution, 0.5 per cent, in 2.5 per cent dextrose (314 mOsm/l). Following sodium bicarbonate infusion (mean dose 6.7 mEq/kg), serum sodium and osmolality immediately increased to 160 mEq/l and 335 mOsm/l, respectively. However, sodium values were similar in the two groups by 15 min after infusion. Although significant differences in PA(O 2) values were not found between groups after infusion, sodium bicarbonate therapy was associated with a significantly higher PA(O 2) value (175 ± 60 torr) than was treatment with saline solution (51 ± 8 torr) in neonates with pH(a)<7.00 before resuscitation. Significant disparities in pH(a) and base excess values occurred between bicarbonate- and saline-treated groups after infusion; two saline-treated lambs died, while all bicarbonate treated lambs survived the study period. Intracranial subarchnoid hemorrhage occurred in three bicarbonate- and in two saline-treated lambs and was apparently related to severe asphyxia and not to the tonicity of the solutions. It is concluded that treatment of neonatal metabolic acidosis with appropriate doses of sodium bicarbonate is not associated with intracranial hemorrhage or sustained hypernatremia in the term neonatal lamb.