USE OF ISOPROTERENOL AND PHENOXYBENZAMINE IN TREATMENT OF ENDOTOXIN SHOCK

¹ Experimental Medicine Division, Directorate of Medical Research, U. S. Army, Edgewood Arsenal, Maryland

Five approaches to the treatment of endotoxin shock in the dog have been evaluated. The effect of endotoxin on physiologic functions and survival was noted. Dogs treated with hydrocortisone, isoproterenol, or a combination of the two showed temporary improvement of the physiological functions monitored. Isoproterenol produced a remarkable increase in right ventricular pressure even as systemic blood pressure decreased. In contrast, hydrocortisone produced a fall in both right ventricular and systemic blood pressures. Treatment with phenoxybenzimine corrected systemic acidosis, increased right ventricular output and resulted in a 73% survival. This occurred even as the arterial blood pressure was maintained at seemingly hypotensive levels. The most remarkable results in this study were obtained with a combination of phenoxybenzamine and isoproterenol. The vasodilation and hypotension produced by phenoxybenzamine appeared to be attenuated by the cardiostimulatory effect of isoproterenol. Thus, flow was maintained to vital tissues and systemic blood pressure was supported at more clinically acceptable levels. This form of combined therapy presents a possible solution to the objection of treating an already seriously hypotensive condition with an agent that further reduces blood pressure.