WITH increasing frequency, bedside measurements of cardiac output and other hemodynamic variables are being made in surgical patients. Considerable effort has been expended in the use of such measurements to control intelligently the administration of fluids and vasoactive drugs.
Isoproterenol appears to be a drug of potential usefulness when the above measurements indicate some element of cardiac failure as shown in experimental1 as well as clinical work.2 The precise hemodynamic actions of this agent are, however, not fully documented.
We have studied the influence of isoproterenol on cardiac output, blood pressure, and blood flows in the vertebral artery and in the left circumflex coronary artery in the dog, and from these data calculated cardiac work and regional as well as total peripheral resistances.
Material and Methods
Adult, healthy mongrel dogs, weighing 23.6 to 36.3 kg (52 to 80 lb) were used for the experiment. Anesthesia was induced with