Background and methods: This study was designed to assess the effect of epinephrine during cardiopulmonary resuscitation (CPR) on left ventricular myocardial blood flow, systemic oxygen delivery and consumption, and on plasma glucose and lactate concentrations. Fourteen pigs were allocated to receive either 0.9% saline (n = 7), or 45 micrograms/kg epinephrine (n = 7) after 5 mins of ventricular fibrillation, and 3 mins of open-chest CPR. Left ventricular myocardial blood flow was measured with radiolabeled microspheres. Plasma catecholamine concentrations were measured by high-pressure liquid chromatography.
Results: During open-chest CPR, mean (+/- SD) values of left ventricular myocardial blood flow before, 90 secs, and 5 mins following drug administration were 49 +/- 10, 46 +/- 12, 43 +/- 15 mL/min/100 g, respectively, in the control group, and 52 +/- 12, 118 +/- 21, 84 +/- 28 mL/min/100 g, respectively, in the epinephrine group (p less than .05 at 90 secs and 5 mins). At the same time points, mean (+/- SD) oxygen delivery indices were 7.7 +/- 3.0, 6.0 +/- 2.1, 6.5 +/- 2.7 mL/min/kg in the control group and 7.6 +/- 2.5, 5.3 +/- 2.1, 5.5 +/- 1.9 mL/min/kg in the epinephrine group (nonsignificant). Mean oxygen consumption indices were 5.8 +/- 2.4, 4.6 +/- 1.6, 5.2 +/- 2.6 mL/min/kg in the control group and 5.4 +/- 1.6, 4.2 +/- 1.6, 4.4 +/- 1.4 mL/min/kg in the epinephrine group (nonsignificant). During CPR and before epinephrine administration, arterial plasma epinephrine concentrations increased from prearrest values of 0.77 +/- 0.70 to 62.1 +/- 48.7 micrograms/L, and plasma norepinephrine concentrations increased from 0.28 +/- 0.32 to 104.3 +/- 57.1 micrograms/L. After administered epinephrine, there was an additional increase to 271 +/- 83 micrograms/L at 90 secs in arterial plasma epinephrine, but no important alteration in the plasma norepinephrine concentration. At no time point could we find a clinically important difference in plasma glucose or lactate concentrations between the two groups.
Conclusions: At a dose of 45 micrograms/kg, epinephrine caused an increase in left ventricular myocardial blood flow after a total of 8 mins of cardiac arrest, including 3 mins of CPR, while not altering systemic oxygen delivery and consumption, plasma glucose, or lactate concentrations.