Acute endotoxin shock in the dog and an attempt at its therapy

The present study aimed at monitoring of hemodynamic changes proceeding in a standard model of acute endotoxin shock in the dog, and mainly at an attempt at the therapy of its early phases. Acute endotoxin shock represents a grave state with rapidly advancing changes in blood circulation, therefore we studied the effects of selected drugs, intended to regulate the circulation conditions in the course of shock. In a standard model in the dog, in which endotoxin shock had been induced by intravenous injection of Escherichia coli endotoxin dosed 1.75 mg.kg-1, the effects of dopamine and hydrocortisone were investigated. The course of the hemodynamic changes can be divided into three phases, as follows. In the first phase, during endotoxin infusion, the blood pressure sank steeply, and the myocardial contractility, left ventricular pressure, and renal arterial blood flow decreased. The central venous pressure rose. After the conclusion of endotoxin infusion the second phase of shock began. It was characterized by a transitory partial correction of hemodynamics. In the third phase all hemodynamic indicators gradually worsened. An especially grave phenomenon was the reduction of renal arterial blood flow. The fatal effects of the administered endotoxin dose were preventable by infusion of dopamine, or hydrocortisone, or their combination. Dopamine plus hydrocortisone raised the survival quota of animals in endotoxin shock, enhanced the renal arterial blood flow, maintained the diuresis, enhanced myocardial contractility, and elevated left ventricular blood pressure.