Epinephrine's effects on cerebrovascular and systemic hemodynamics during cardiopulmonary resuscitation.
BACKGROUND
Despite controversies, epinephrine remains a mainstay of cardiopulmonary resuscitation (CPR). Recent animal studies have suggested that epinephrine may decrease cerebral blood flow (CBF) and cerebral oxygenation, possibly potentiating neurological injury during CPR. We investigated the cerebrovascular effects of intravenous epinephrine in a swine model of pediatric in-hospital cardiac arrest. The primary objectives of this study were to determine if (1) epinephrine doses have a significant acute effect on CBF and cerebral tissue oxygenation during CPR and (2) if the effect of each subsequent dose of epinephrine differs significantly from that of the first.


METHODS
One-month-old piglets (n = 20) underwent asphyxia for 7 min, ventricular fibrillation, and CPR for 10-20 min. Epinephrine (20 mcg/kg) was administered at 2, 6, 10, 14, and 18 min of CPR. Invasive (laser Doppler, brain tissue oxygen tension [PbtO2]) and noninvasive (diffuse correlation spectroscopy and diffuse optical spectroscopy) measurements of CBF and cerebral tissue oxygenation were simultaneously recorded. Effects of subsequent epinephrine doses were compared to the first.


RESULTS
With the first epinephrine dose during CPR, CBF and cerebral tissue oxygenation increased by > 10%, as measured by each of the invasive and noninvasive measures (p < 0.001). The effects of epinephrine on CBF and cerebral tissue oxygenation decreased with subsequent doses. By the fifth dose of epinephrine, there were no demonstrable increases in CBF of cerebral tissue oxygenation. Invasive and noninvasive CBF measurements were highly correlated during asphyxia (slope effect 1.3, p < 0.001) and CPR (slope effect 0.20, p < 0.001).


CONCLUSIONS
This model suggests that epinephrine increases CBF and cerebral tissue oxygenation, but that effects wane following the third dose. Noninvasive measurements of neurological health parameters hold promise for developing and directing resuscitation strategies.
['Mavroudis|Constantine D|CD|', 'Ko|Tiffany S|TS|', 'Morgan|Ryan W|RW|', 'Volk|Lindsay E|LE|', 'Landis|William P|WP|', 'Smood|Benjamin|B|', 'Xiao|Rui|R|', 'Hefti|Marco|M|', 'Boorady|Timothy W|TW|', 'Marquez|Alexandra|A|', 'Karlsson|Michael|M|', 'Licht|Daniel J|DJ|', 'Nadkarni|Vinay M|VM|', 'Berg|Robert A|RA|', 'Sutton|Robert M|RM|', 'Kilbaugh|Todd J|TJ|']
D000818:Animals D001784:Blood Gas Analysis D001794:Blood Pressure D016887:Cardiopulmonary Resuscitation D002561:Cerebrovascular Disorders D004195:Disease Models, Animal D004837:Epinephrine D006439:Hemodynamics D013552:Swine
Cardiopulmonary resuscitation Cerebral blood flow Diffuse correlation spectroscopy Diffuse optical spectroscopy Cerebral blood flow and metabolism