707 - Effect of Epinephrine on the Coronary Circulation During Neonatal Resuscitation using a Large Ovine Bradycardic Model

Poster Number: 707
Publication Number: 707.445

Mausma Bawa, Boston Children's Hospital, Brookline, MA, United States; Sylvia F. Gugino, State University of New York at Buffalo, Buffalo, NY, United States; Justin Helman, University at Buffalo, Grand Island, NY, United States; Nicole Bradley, University at Buffalo, Buffalo, NY, United States; Lori C. Nielsen, SUNY Buffalo, buffalo, NY, United States; Arun Prasath, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Clariss Blanco, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Mary Divya Kasu, John R. Oishei Children's Hospital, Buffalo, NY, United States; Hamza F.. Abbasi, University at Buffalo, east amherst, NY, United States; Munmun Rawat, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Praveen Chandrasekharan, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States

Background: Epinephrine (EPI) is the only drug used in extensive neonatal resuscitation. Previous studies using the adult canine model of myocardial infarction have debated the effect of constriction vs. dilation of coronary vasculature during resuscitation. There are no studies in neonates or in a neonatal resuscitation model to understand epinephrine's effect on myocardial perfusion.

Objective: To understand the effect of EPI administration on coronary blood flow using a bradycardia ovine model during neonatal resuscitation. Both in-vivo and in-vitro effects of EPI were evaluated. Using a vessel bath, coronary and carotid vasculature responses to EPI as a percentage of potassium chloride response was elicited.

Design/Methods: For the in-vivo data, four near-term bradycardic ovine models who required EPI (0.03 mg/kg with 3ml flush) were resuscitated per the neonatal resuscitation program recommendation until the return of spontaneous circulation (ROSC) or until 20 min. Coronary, carotid blood flows were recorded continuously during resuscitation. Coronary and carotid vessels were obtained from 6 near-term lambs not included in the protocol, and the effect of epinephrine studies (graded molar solution) in a vessel bath using Kreb's solution as a percentage of potassium chloride (KCl) response (KCl elicits the maximum response of any vessel).

Results: All four lambs achieved ROSC. There was a significant increase in the peak coronary blood flow before and after administering EPI (figure 1) during CC.  Post-EPI administration, there was a significant increase in diastolic blood pressure (DBP) (figure 1). There was a non-significant increase in carotid blood flow during CC after EPI administration (figure 2). There was no coronary vasoconstriction as a percentage of KCl constriction, while there was a higher carotid vasoconstriction with EPI as a percentage of KCl constriction (figure 3).

Conclusion(s): EPI increased myocardial perfusion by increasing diastolic blood pressure and coronary blood flow in a transitioning bradycardia model superimposed with CC not synchronized with existing cardiac rhythm. Using an in-vitro vessel bath study, EPI did not constrict coronary vessels. Our finding supports the current safe practice of using EPI as a sole drug during neonatal resuscitation to revive the myocardial function.