American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the effect of dobutamine on cardiac output?

1. It decreases cardiac output

2. It has no effect on cardiac output

3. It increases cardiac output

4. It primarily affects alpha receptors

The correct answer is: It increases cardiac output

Dobutamine is a synthetic catecholamine that primarily acts as a beta-1 adrenergic agonist, leading to increased myocardial contractility and heart rate. By stimulating the beta-1 receptors in the heart, dobutamine enhances cardiac contractility (positive inotropic effect) and can also have a mild positive chronotropic effect at higher doses. This improvement in the strength of heart contractions directly contributes to an increase in cardiac output. In clinical practice, dobutamine is often used in patients with heart failure or other conditions where increased cardiac output is desired, such as in certain forms of shock. The ability of dobutamine to significantly boost cardiac output makes it a valuable therapeutic agent in the management of various cardiac conditions, distinguishing it from other substances that may not influence cardiac function in the same manner.