Protective effects of epinephrine tolerance in experimental cardiogenic shock.

To evaluate the mechanism of protection of epinephrine tolerance in shock, we studied the hemodynamic and regional blood flow response to cardiogenic shock in dogs rendered tolerant to lethal doses of epinephrine. Shock was induced by coronary embolization. Regional organ perfusion was evaluated with radioactive microspheres. The survival of tolerant dogs following embolization was 8/12 (62%) compared to 5/31 (16%) in control dogs (P = 0.008). Heart and adrenal organ weights were significantly greater in the tolerant animals. Ventricular hypertrophy in the tolerant dogs was accompanied by greater myocardial blood flow and greater myocardial contractility both before and during cardiogenic shock. There was significantly greater regional flow to spleen, gastrointestinal tract, and pancreas during shock in the epinephrine-tolerant group.