Effect of Pressor Amines on Cardiac Output in Patients with Acute Hypotension

Abstract

Intra-arterial pressure, central venous pressure, and cardiac output were recorded in 14 patients with acute hypotension (shock), and 5 patients during recovery from shock. Metaraminol and levarterenol were administered by intravenous infusion, and serial measurements of these hemodynamic variables were made. Despite increases in total peripheral resistance, a decrease in cardiac output after infusion of vasopressor agents was observed in only one patient. With moderate elevations of arterial pressure, cardiac output was increased. With further elevation of arterial pressure, no additional increase in cardiac output was detected, but neither was a decline observed. These observations do not support the contention that vasopressor amines, through their vasoconstrictor effect, reduce the total systemic blood flow when used for the treatment of shock in man.