The 7th edition of the Textbook of Neonatal
Resuscitation recommends administration of
epinephrine via an umbilical venous
catheter (UVC) inserted 2-4 cm below the skin, followed by a 0.5-mL to 1-mL flush for severe
bradycardia despite effective ventilation and chest compressions (CC). This volume of flush may not be adequate to push
epinephrine to the right atrium in the absence of intrinsic cardiac activity during CC. The objective of our study was to evaluate the effect of 1-mL and 2.5-mL flush volumes after UVC
epinephrine administration on the incidence and time to achieve return of spontaneous circulation (ROSC) in a near-term ovine model of perinatal
asphyxia induced cardiac arrest. After 5 min of
asystole, lambs were resuscitated per Neonatal
Resuscitation Program (NRP) guidelines. During
resuscitation, lambs received
epinephrine through a UVC followed by 1-mL or 2.5-mL
normal saline flush. Hemodynamics and plasma
epinephrine concentrations were monitored. Three out of seven (43%) and 12/15 (80%) lambs achieved ROSC after the first dose of
epinephrine with 1-mL and 2.5-mL flush respectively (p = 0.08). Median time to ROSC and cumulative
epinephrine dose required were not different. Plasma
epinephrine concentrations at 1 min after
epinephrine administration were not different. From our pilot study, higher flush volume after first dose of
epinephrine may be of benefit during neonatal
resuscitation. More translational and clinical trials are needed.