Clinical paperEffects of epinephrine on cerebral oxygenation during cardiopulmonary resuscitation: A prospective cohort study

BackgroundEpinephrine has been presumed to improve cerebral oxygen delivery during cardiopulmonary resuscitation (CPR), but animal and registry studies suggest that epinephrine-induced capillary vasoconstriction may decrease cerebral capillary blood flow and worsen neurological outcome. The effect of epinephrine on cerebral oxygenation (rSO2) during CPR has not been documented in the clinical setting.MethodsrSO2 was measured continuously using cerebral oximetry in patients with in-hospital cardiac arrest. During CPR, time event markers recorded the administration of 1 mg epinephrine. rSO2 values were analysed for a period beginning 5 min before and ending 5 min after the first epinephrine administration.ResultsA total of 56 epinephrine doses were analysed in 36 patients during CPR. The average rSO2 value in the 5-min following epinephrine administration was 1.40% higher (95% CI = 0.41-2.40%; P = 0.0059) than in the 5-min period before epinephrine administration. However, there was no difference in the overall rate of change of rSO2 when comparing the 5-min period before, with the 5-min period immediately after a single bolus dose of epinephrine (0.88%/min vs 1.07%/min respectively; P = 0.583), There was also no difference in the changes in rSO2 at individual 1, 2, 3, or 4-min time windows before and after a bolus dose of epinephrine (P = 0.5827, 0.2371, 0.2082, and 0.6707 respectively).ConclusionsA bolus of 1 mg epinephrine IV during CPR produced a small but clinically insignificant increase in rSO2 in the five minutes after administration. This is the first clinical data to demonstrate the effects of epinephrine on cerebral rSO2 during CPR.