ANGIOTENSIN-II IMPROVES MYOCARDIAL BLOOD-FLOW IN CARDIAC-ARREST

Epinephrine is used to increase coronary perfusion pressure and improv e myocardial blood flow during cardiac arrest. Alternative vasopressor s may have hemodynamic advantages over epinephrine. The purpose of thi s investigation was to test the effect of the vasopressor angiotensin II on myocardial blood flow in a swine model of cardiac arrest. Eleven swine were anesthetized and instrumented for regional blood flows by radiolabeled microsphere technique. A baseline blood flow measurement (BFM), coronary sinus and aortic blood gases were obtained in normal s inus rhythm (NSR). Ventricular fibrillation (VF) was induced and mecha nical CPR begun after 10 min of VF. A BFM and blood gases were obtaine d during CPR. Angiotensin II, 50 mug/kg, was administered at 13 min of VF. A repeat BFM and blood gases were obtained following angiotensin II. Defibrillation was attempted at 16.5 min of VF. If return of spont aneous circulation (ROSC) occurred a fourth BFM and blood gases were o btained. Myocardial blood flow was 134.2 +/- 40.1 ml/100 g per min dur ing NSR. This fell to 15.1 +/- 19.9 with CPR alone, and rose to 66.9 /- 69.8 following angiotensin II administration (P = 0.04; by two tail ed T-test). Myocardial blood flow following ROSC further increased to 212.6 +/- 58.0. Angiotensin II in a dose of 50 mug/kg significantly in creases myocardial blood flow in this model of cardiac arrest.