The Effect of Rapid Vs. Slow Injection of Sodium Bicarbonate on Cerebral Oxygenation and Hemodynamics in Preterm Infants with Metabolic Acidosis

Abstract 1219 Poster Session IV, Tuesday, 5/4 (poster 269)

Objective: To compare the effect of rapid vs. slow injection of sodium bicarbonate on cerebral oxygenation and hemodynamics in preterm infants with metabolic acidosis.

Methods: Twenty one preterm infants with metabolic acidosis (base deficit < -6 mmol/L) were randomized in 2 groups. Group 1 (n=13, GA 31.7±1.3 wk, BW 1457±376 g) was treated with a rapid injection of sodium bicarbonate 4.2% (1.1±0.3 mmol/kg); Group 2 (n=8, GA 31.3±1.6 wk, BW 1480±279 g) was treated with a slow injection (in 30 min) of sodium bicarbonate 4.2% (1.1±0.2 mmol/kg). The concentration changes of oxyhemoglobin (ΔcO₂Hb), deoxyhemoglobin (ΔcHHb) and total hemoglobin (ΔctHb) in cerebral tissue (in µmol/100 g), were continuously measured with near infrared spectrophotometry (NIRS). ΔcO₂Hb and ΔcHHb reflect changes in cerebral O₂ supply, while ΔctHb reflects changes in cerebral blood volume. Changes in cerebral blood flow velocity (ΔCBFV) in the internal carotid artery (expressed as percentage of the preinjection value) were determined with pulsed Doppler ultrasound before and at 5, 15, 30 and 45 min after the start of the injection. Heart rate, blood pressure, arterial O₂ saturation, tcpO₂ and tcpCO₂ were continuously recorded.

Results: (mean ± SD) (Table) The NIRS and the other variables did not change significantly within and between the groups.

Table 1 No caption

Conclusion: No changes in cerebral oxygenation and hemodynamics were found after rapid as well as slow injection of sodium bicarbonate in preterm infants with metabolic acidosis. The use of rapid injection of sodium bicarbonate in preterm infants as therapy of metabolic acidosis is justified.