There is increasing evidence that the combination of epinephrine (adrenaline) with vasopressin may be superior to either epinephrine or vasopressin alone for treatment of cardiac arrest. However, the optimal combination, and dosage of cardiovascular drugs to minimize side effects, and to improve outcome has yet to be found. We therefore evaluated whether the combination of vasopressin plus epinephrine plus nitroglycerin (EVN), would improve vital organ blood flow during cardiopulmonary resuscitation (CPR) when compared with epinephrine (EPI) alone. After 4 min of ventricular fibrillation (VF) and 4 min of standard CPR, pigs were randomized to the combination of epinephrine (45 μg/kg) plus vasopressin (0.4 U/kg) plus nitroglycerin (7.5 μg/kg; n=12), or epinephrine (40 μg/kg; n=12) alone. Cerebral and myocardial blood flow was measured with radiolabeled microspheres. Defibrillation was attempted after 19 min of VF including 15 min of CPR. Mean±SEM coronary perfusion pressures were significantly (P<0.01) higher 5 min after EVN vs. EPI alone (34±3 vs. 24±3 mmHg, respectively). At the same time, mean±SEM left ventricular, and global cerebral blood flow was also significantly (P<0.05) higher after EVN vs. EPI alone (0.78±0.11 vs. 0.48±0.08 ml/min/g; and 0.37±0.05 vs. 0.22±0.0 3 ml/min/g, respectively). Spontaneous circulation was restored in 11 of 12 animals in the EVN group vs. 6 of 12 swine after EPI alone (P=N.S.). In conclusion, the combination of EVN significantly improved vital organ blood flow during CPR compared with EPI alone. Addition of nitroglycerin to the combination of low dose epinephrine with vasopressin during cardiac arrest may be beneficial.
Bibliographical noteFunding Information:
The authors would like to thank Pam Sukhum and Colleen Peterson for their technical assistance. Supported, in part, by the Cardiac Arrhythmia Center, University of Minnesota, Minneapolis, USA; and the Department of Anesthesiology and Critical Care Medicine, Leopold-Franzens-University, Innsbruck, Austria.
- Cardiopulmonary resuscitation
- Cerebral blood flow
- Myocardial blood flow