Aims Neonatal hypotension affects 50% of patients within NICU, and is commonly treated with inotropes such as dopamine and dobutamine. Our unit reports instances of reduced mean arterial pressures (MAP) towards the end of 24 hour infusions, occasional IV line discolouration, and rapid spikes of MAP on the start of new infusions. In this study we investigated the possible effects of temperature and ambient lighting on drug stability during continuous infusion.

Methods Syringe-driver infusions were set up of either dopamine (MercuryPharma) or dobutamine (Wockhardt), diluted with either 0.9% normal saline (NS) or 5% glucose, delivering 3 mcg/ kg/min and 5 mcg/kg/min respectively via 206 cm extension sets. Infusions were run over 24 hours protected or exposed to ambient lighting and approximately half the tubing was incubated at 35°C. Concentration was measured using cyclic voltammetry, at the start and end of infusion, collecting samples from the syringe and infusion terminal.

Results A significant decrease in the concentration of dopamine after 24 hours was observed when prepared in 0.9% NS. Dobutamine shows no significant degradation when prepared in 0.9% NS or 5% glucose over 24 hours. In the absence of light, dopamine prepared in 0.9% NS shows neither improvement nor worsening degradation compared with the exposure of light.

Conclusion This study finds significant inotrope degradation over a 24 hour intravenous infusion. Much more research is needed to elicit the multifactorial mechanisms behind the harmful MAP fluctuations in treating neonatal hypotension of which degradation could be a potentially instrumental factor.