Special article: Hemodynamic Effects of Ganglion Blocking Drugs

Abstract

The hemodynamic effects are reasonably certain for tetraethylammonium and hexamethon-ium, but not for the other 6 ganglion blocking drugs. All ganglion blocking agents initiate the same hemodynamic pattern in man, as follows The fall in systemic blood pressure is caused by a reduction in systemic vascular resistance and by a reduction in cardiac output. The latter is not a consistent cause and may even increase, particularly in patients in heart failure or with mitral stenosis. Blood flows to the various organs are usually decreased, but an increase may occur to the extremities. The calculated vascular resistance is reduced in the cerebral and coronary vessels, is variable in the renal vessels and uncertain in the splanchnic and extremities. The response of pulmonary vascular resistance is also variable, but pulmonary arterial pressure usually falls. A consideration of the changes in organ vascular resistance induced by ganglion blockade, supports the existence of a local vascular adjustment of the cerebral vessels so that they are dilated when pressure is reduced. The behavior of the renal and splanchnic vessels is just the opposite, and is unknown for the other beds. In addition to this local adjustment, the role of blockade of the autonomic ganglia to the various vascular beds should be considered. The renal, splanchnic and the limb vessels have more abundant sympathetic vasoconstrictor tone, yet a release of these impulses by ganglion blocking drugs is not apparent from the available results.