Acute Hemodynamic Effects of Dopamine in Patients with Shock

The hemodynamic effects of dopamine were studied in 62 patients with clinical shock. In 36 patients with infection dopamine increased mean arterial pressure (MAP) 30%, and cardiac output (CO) 37%. Urine flow (UF) increased from 0.5 ml/min to 1.6 ml/min. Norepinephrine (NE) in 26 patients resulted in a higher MAP, lower CO, and similar UF. Isoproterenol (Isp) in 19 patients resulted in a lower MAP, higher CO, and a significantly lower UF. In 13 patients with cardiogenic shock dopamine increased MAP 6%, and CO 40%. UF increased from 0.6 ml/min to 1.1 ml/min. NE in eight patients resulted in a lower CO than during dopamine infusion, and Isp in five patients resulted in a higher CO. Dopamine improves MAP pressure, CO, and UF when shock is due to infection and is superior to Isp which does not increase perfusion pressure to adequate levels and does not improve UF. In patients with cardiogenic shock who have reduced CO and increased systemic vascular resistance, perfusion pressure tended to be adequate, and improved CO occurred with dopamine and Isp but not with NE. Although Isp increased CO more than dopamine, differences in regional perfusion are important in selection of the best inotropic agent and in most patients make dopamine the preferred agent.