Histamine and sympathetic blockade in septic shock.

The relative roles of endogenously released histamine and the sympathetic nervous system in septic shock were indirectly studied by blocking each one separately. Antihistamines in doses of 3-10 mg/kg prevented severe blood pressure drops and improved urinary output in groups treated before and after shock. Release of histamine seems to be important at least in the pathogenesis of early septic shock, although analysis of blood pressure pattern and survival implicates additional factors in late shock. Epidural block in combination with E. coli injection was detrimental, producing severe hypotension and even immediate death. Neural sympathetic tone is essential to survival in shock.