Addition of Epinephrine (Epi) to Dopamine (DA) Increases Blood Pressure (BP) and Urine Output (Uv) in Critically Ill Extremely Low Birthweight Neonates(ELBW) with Uncompensated Shock † 1131

Critically ill ELBW may present with systemic hypotension and oliguria/anuria unresponsive to combined DA and dobutamine (DOB) administration at “conventional” doses (20-30 μg/kg/min). In such cases, further escalation of DA treatment or addition of Epi infusion(with or without administration of stress doses of hydrocortisone) may be effective in the management of systemic hypotension. However, the addition of Epi carries the theoretical risk of severe alpha receptor-mediated renal vasoconstriction, resulting in further decreases in Uv. Since no data are available on the potential oliguric effect of Epi in the neonate, we reviewed the cardiovascular and renal response to Epi in 5 ELBW (GA=26.6±2.3 weeks; BW=894±183 g; postnatal age=23.2±12.4 days) who received the drug at a dose range of 0.05-0.3 μg/kg/min, when DA alone (14-26μg/kg/min, n=2) or in combination with DOB (10-15 μg/kg/min, n=3) failed to increase BP effectively (Table, mean±SD,(range); *=P<0.05 vs “Pre-Epi”, paired t test). One patient received Epi on two different occasions. Results: BP increased within the first 2 hours of Epi infusion. Uv also tended to increase during the first 24 hours of Epi (“Epi”) compared to the 12 hours before the start of Epi (“Pre-Epi”), but this increase was not significant (P>0.05). However, in the 3 patients with the lowest Uv during the Pre-Epi period (Uv<2.0 mL/kg/hour), Epi increased Uv significantly. Total volume administration was unchanged during the two periods (7±2 vs 7.1±1.2 mL/kg/h). DOB was weaned off in 2 of the 3 ELBW within 2 hours of Epi treatment. Three of the patients survived.

Table 1 No caption available.

Conclusions: 1) Critically ill ELBW with shock unresponsive to “conventional” doses of DA/DOB treatment may respond to the addition of Epi with normalization of systemic BP. 2) Epi, at the doses applied, does not induce oliguria in ELBW. Speculation: Down-regulation of the cardiovascular alpha receptors in severe disease states may explain the lack of the Epi-induced oliguria/renal vasoconstriction as well as the need for higher doses of pressors to normalize BP in the critically ill ELBW with uncompensated shock.