Abstract 211: Epinephrine Does Not Correct Post-ROSC Hypoperfusion Despite Normalizing Blood Pressure A Rat Model Of Severe Pediatric Asphyxial Cardiac Arrest

Abstract

In children resuscitated from cardiac arrest, systemic hypotension occurs frequently and is associated with worse outcome. The first-line vasoactive treatment for post-arrest hypotension is continuous infusion of epinephrine. Epinephrine dose is titrated to maintain normal blood pressure for age. Epinephrine, however, also leads to vasoconstriction which may impair organ perfusion after resuscitation.We hypothesized that epinephrine infusion during the post-resuscitation period restores systemic blood pressure but not flow to vital organs. Using a model of severe pediatric asphyxial cardiac arrest in developing rats, we simultaneously measured blood pressure (ABP) and flow in carotid (Fc) and femoral (Ff) arteries after resuscitation. We then compared the effects of epinephrine or saline infusions on blood pressure vs flow. One hour after resuscitation from 11.5 minutes of asphyxial arrest, ABP, Fc and Ff were 61.73 ± 2.68; 42.58 ± 3.84; and 19.53 ± 7.00 % of baseline. Epinephrine infusion increased ABP in a dose-dependent manner, reaching 95.13 ± 7.93 % of baseline at 0.5 μg/kg/min. Saline infusion at equivalent volumes increased ABP only marginally to 69.88 ± 2.60 % of baseline. In contrast to its effect on ABP, epinephrine infusion increased Fc only to 49.55 ± 6.49 and Ff to 53.28 ± 7.13 % of baseline. Saline infusion at equivalent volumes, on the other hand, had a more salutary effect than epinephrine on improving blood flow (Fc 64.62 ± 6.64 and Ff 60.25 ± 7.60 % of baseline). Notably, a single 10 cc/kg saline bolus, administered when ABP decreased to ~80% of baseline post-ROSC, increased blood flow and ABP to 100% and 90% of baseline, respectively. These data indicate that epinephrine infusion in the post-arrest period adversely affects arterial blood flow despite normalizing arterial blood pressure. Continued fluid resuscitation with crystalloids potentially has beneficial effect on correcting post-ROSC hypoperfusion. Future studies need to explore the impact of targeting flow rather than blood pressure in the post-arrest period and its association to post-arrest end-organ function in children.