Hemodynamic effects of sodium bicarbonate administration

To describe the hemodynamic changes that occur with sodium bicarbonate (NaHCO₃) administration in premature neonates.

This retrospective study included premature neonates 23 to 31+6 weeks of gestational age who underwent continuous cardiac and cerebral monitoring as participants in prospective trials at our institution, and who received NaHCO₃ infused over 30 min in the first 24 h of life. Blood pressure (BP), heart rate, cardiac output (CO), SpO₂ and cerebral oximetry (StO₂) were captured every 2 s. A baseline was established for all continuous data and averaged over the 10 min before NaHCO₃ administration. Baseline was compared with measurements over 10 min epochs until 80 min after administration. Arterial blood gases before and within 1 h of administration were also compared. Significance was set at P<0.05.

A total of 36 subjects received NaHCO₃ (1.3±0.3 mEq kg^-1) in the first 24 h (14±8.5 h) of life. NaHCO₃ administration increased pH (7.23 vs 7.28, P<0.01) and decreased base deficit (-8.9 vs -6.8, P<0.01) and PaCO₂ (45 vs 43 mm Hg, P<0.05). There was a transient but significant (P<0.05) decrease in systemic BP coinciding with an increase in cerebral oxygenation without an increase in oxygen extraction. CO did not change.

Early postnatal NaHCO₃ administration does not acutely improve CO but does cause transient fluctuations in cerebral and cardiovascular hemodynamics in extremely premature infants.