Hemodynamic Defects Underlying Shock with Indications for Treatment: An Appraisal of Vasopressors and Vasodilators

Abstract

Until the sphygmomanometer came into wide use after 1910, the character and rate of the pulse served as the primary objective measure of severity of circulatory failure. Subsequently, blood pressure became an index for both the diagnosis and estimation of severity of the shock state. In the search for therapy by which hypotension could be reversed, the clinician was attracted to drugs restoring blood pressure to more normal levels. This led to the early use of epinephrine and the subsequent use of its adrenergic analogs. Beginning in the 1940s synthetic adrenergic drugs came into wide use for treatment of shock states. Unlike epinephrine, phenylephrine and methaxamine increased blood pressure but more often decreased the heart rate. Except for the relatively conservative use of fluids, blood, blood components, and blood substitutes, vasopressor drugs were until recently the mainstay of therapy for shock, regardless of cause.