The Annals of Thoracic Surgery, Vol 29, 26-31, Copyright © 1980 by The Society of Thoracic Surgeons
The use of levarterenol and phentolamine in patients with low cardiac output following open-heart surgery
MM Kirsh, E Bove, M Detmer, A Hill and P Knight
A study was made of the hemodynamic effects of levarterenol and
phentolamine in patients in whom low cardiac output developed following
open-heart operation. After the patients were weaned from cardiopulmonary
bypass, the inotropic agents were infused into an external or internal
jugular vein through an IVAC pump. Levarterenol was administered first
until systolic arterial pressure rose 20 to 30% above the higest recorded
preoperative pressure. After stabilization, phentolamine was administered,
and infusion rates were adjusted so that arterial blood pressure was
returned to levels measured before bypass. After infusion, all patients
showed an increase in cardiac index, mean arterial pressure, mean stroke
volume index, and left ventricular stroke work index. Mean pulmonary artery
pressure, pulmonary vascular resistance, and left atrial pressure decreased
in all patients. This study demonstrates that hemodynamic improvement
occurs in humans in low cardiac output state with simultaneous infusion of
levarterenol and phentolamine. We recommend these agents for use in
patients with low output, unless they continue to receive propranolol
during and after operation. Patients on a regimen of propranolol should not
be given levarterenol and phentolamine.
