Vasopressor Effect of Epinephrine with and without Dopamine during Cardiopulmonary Resuscitation

Abstract

We prospectively studied nine prehospital cardiac arrest patients (six M, three F; aged 60 ± 8 yr) to determine the vasopressor response following incremental (1, 3, and 5 mg) doses of intravenous epinephrine given 5 minutes apart with or without dopamine 15 μg/kg/min. All patients were in ventricular fibrillation on arrival of the paramedics and were not resuscitated with standard advanced cardiac life support therapy. Cardiopulmonary resuscitation (CPR) was performed with a computerized Thumper at 60 compressions/min with a 50:50 downstroke-to-upstroke ratio. All patients were intubated and received 12 ventilations/min at a fraction of inspired oxygen of 80 percent. Radial artery pressure was monitored through a #20 gauge radial artery catheter inserted by cutdown within ten minutes after arrival at the emergency room. Five patients received epinephrine alone (group A) and four received epinephrine plus dopamine (group B). The patient's age, paramedic response time, arterial blood gases, and initial diastolic blood pressure (BP) did not differ significantly between treatment groups. Baseline systolic BP was significantly higher (p < 0.01) in group B (68 ± 10 mm Hg) than in group A (35 ± 5 mm Hg). Epinephrine produced a dose-dependent vasopressor response in group A, but not in group B. In group A, peak systolic BP following epinephrine 1, 3, and 5 mg was 57 ± 20, 69 ± 23, and 76 ± 27 mm Hg, respectively (p < 0.05 for 5 mg vs. baseline). No statistically significant difference was observed among the respective values in group B (81 ± 13, 80 ± 18, and 78 ± 19 mm Hg). In group A, peak diastolic BP following epinephrine 1, 3, and 5 mg was 24 ± 8, 28 ± 16, and 31 ± 6 mm Hg, respectively (p < 0.05 for epinephrine 5 mg vs. baseline). No statistically significant difference was observed among the respective values in group B (33 ± 10, 33 ± 11, and 34 ± 13 mm Hg). Epinephrine produces a dose-dependent vasopressor response during CPR in humans. The administration of high doses of epinephrine to patients receiving high-dose dopamine does not produce an additive vasopressor response.