Cardiovascular effects of sustained norepinephrine infusions. 1. Hemodynamics.

• In the past ten years sustained infusions of Z-norepinephrine (NE) have been used in the treatment of cardiogenic hypotension. In many of the reports the poor results and low rates of survival have been attributed to the severity of the underlying myocardial disease. Detailed studies of the cardiovascular effects of NE have focused on the hemodynamic changes during acute infusions of this catecholamine.' During these short-term infusions norepinephrine increased peripheral vascular resistance and exerted a positive inotropic effect upon the myocardium. The cardiovascular effects of prolonged NE infusion are less clearly defined. Excessive doses of catecholamines administered to experimental animals have produced diffuse myocardial destruction.' The purpose of this study was to investigate the hemodynamic changes in the cardiovascular system during prolonged infusions of relatively physiologic doses of NE.