Understanding the Stability of Dopamine and Dobutamine Over 24h in Simulated Neonatal Ward Conditions.

Abstract

Our objectives were to investigate the possible effects of temperature and light on the stability of dopamine and dobutamine continuous infusions over 24h when prepared in a variety of dilution vehicles. Syringe-driver infusion apparatuses were set up for dopamine and dobutamine diluted with either 0.9% sodium chloride (NaCl) or 5% glucose delivering 3 and 5μg/kg/min, respectively, via 206-cm extension sets. All infusions were prepared for a neonate weight of 1kg. Infusions were run over 24h with approximately half the tubing within an incubator set at 35°C. Cyclic voltammetry was used to monitor the concentration of the inotrope within the syringe and at the end of the extension set, both initially and after 24h. The variation in the concentration of dopamine and dobutamine in the vials (n=6) was 3.58 and 1.22%, respectively. This variation increased to 10.88% for dopamine and 5.76% for dobutamine in the syringe. After 24h, a significant reduction in the concentration of dopamine was observed at the end of the extension set when prepared in 0.9% NaCl versus 5% glucose (p<0.001; n=6-7) and in dobutamine when prepared in 0.9% NaCl (p<0.001; n=6-7). No differences in the concentration of dopamine prepared in 0.9% NaCl were observed after 24h in light-exposed and light-protected extension sets (n=6-7). Dobutamine is more stable in dilution vehicles than dopamine, and inotropes are more stable in the 5% glucose dilution vehicle than in 0.9% NaCl. Such findings will provide guidance on the choice of inotropes.