Comparison of different doses of epinephrine on myocardial perfusion and resuscitation success during cardiopulmonary resuscitation in a pig model

Abstract

Published results of dose-response effects of adrenergic drugs (epinephrine [E]) vary so much between studies because of differences in animal models and duration of ischemia before drug administration. In this investigation the effects of different doses of E on coronary perfusion pressure (CPP), left ventricular myocardial blood flow (MBF) and resuscitation success were compared during closed-chest cardiopulmonary rest scitation (CRP) after a 4-minute period of ventricular fibrillation in 28 pigs. MBF was measured during normal sinus rhythm using tracer microspheres. After 4 minutes of ventricular fibrillation CPR was performed with the use of a pneumatic piston compressor. After 4 minutes of mechanical measures only, the animals were randomly allocated into four groups of seven, receiving 0.015, 0.030, 0.045, and 0.090 mg/kg E intravenously respectively. MBF measurements were started 45 seconds after E administration; hemodynamic measurements after 90 seconds. Four minutes after the first administration, the same E dose was given before defibrillation. The CPP of animals given 0.015, 0.030, 0.045 and 0.090 mg/kg E were as follows: 16.3 ± 6.1, 25.6 ± 5.8, 33.2 ± 8.4 and 30.4 ± 6.3 mm Hg. The left ventricular MBF values were: 14 ± 9, 27 ± 11, 43 ± 6, 46 ± 10 mL/min/100 g. The differences between the groups receiving 0.015 and 0.045 mg/kg and between the groups receiving 0.015 mg/kg and 0.090 mg/kg were statistically significant ( P < .05). Resuscitation success was 14.3%, 42.9%, 100% and 86.7% respectively. A significant difference in resuscitation success was found only betwen 0.015 mg/kg and 0.045 mg/kg E. Our results suggest that after a 4-minute period of arrest and 4 minutes of CPR, CPP, MBF and resuscitation success are increased when E is given at a dosage of up to 0.045 mg/kg; however, the increase to 0.090 mg/kg does not lead to any further improvement.