Intra-aortic administration of epinephrine above aortic occlusion does notalter outcome of experimental cardiopulmonary resuscitation

Intra-aortic balloon occlusion during experimental cardiopulmonary resuscit ation (CPR) improves coronary perfusion pressure and resuscitability and pr ovides unique access to the central circulation. It has been hypothesized t hat administration of epinephrine into the aortic arch in combination with aortic occlusion would further improve haemodynamics during CPR, resuscitab ility and 24 h survival. In 16 anaesthetised dogs intravascular catheters w ere placed for hemodynamic and blood gas monitoring. An aortic balloon cath eter was placed by femoral artery insertion with its tip just distal to the left subclavian artery. Ventricular fibrillation for 7.5 min without CPR, 2.5 min of Basic Life Support with chest compressions and ventilation with 100% oxygen were followed by 30 min of Advanced Cardiac Life Support (ACLS) with systemic canine drug dosages. The intra-aortic balloon was inflated w hen ACLS started and gradually deflated shortly after restoration of sponta neous circulation (ROSC). Epinephrine, in 100 mu g/kg boluses every 5 min u ntil the heart was restarted or 30 min had elapsed was administered through the intra-aortic catheter in the experimental group (n = 8) and via a cent ral venous catheter in the control group (n = 8). Coronary perfusion pressu re increased during the ACLS period in both groups (P < 0.05) with no diffe rence between the groups and there was no difference in the frequency of RO SC (experimental group 5/8, control group 4/8). Furthermore with respect to 24 h survival, there was no difference between the experimental group (2/8 ) and the control group (3/8). Severe macroscopic haemorrhagic necrosis of the myocardium in the dogs with ROSC was found in 4/5 in the experimental g roup compared to 1/4 in the control group. In conclusion, intra-aortic admi nistration of 100 mu g/kg epinephrine doses combined with aortic occlusion during experimental CPR did not alter outcome. (C) 1999 Elsevier Science Ir eland Ltd. All rights reserved.