How can we increase myocardial contractility to raise stroke volume and cardiac output in a trauma patient?

• A. Dopamine
• B. Dobutamine
• C. Epinephrine
• D. Norepinephrine

Answer: (B)

Increasing myocardial contractility, or positive inotropy, strengthens the heart’s squeeze, raising stroke volume and cardiac output. In a trauma patient, you want an agent that boosts contractility without driving up afterload too much. Dobutamine does exactly this: it mainly stimulates beta-1 receptors on the heart, enhancing contractility and thus stroke volume, with some beta-2–mediated mild vasodilation that can lower afterload a bit. That combination tends to improve cardiac output when the limiting factor is the heart’s pump strength, without the pronounced vasoconstriction seen with other agents. By contrast, drugs that cause more vasoconstriction or markedly increase heart rate and afterload can worsen perfusion or oxygen demand. So dobutamine is the best fit for increasing contractility to raise stroke volume and cardiac output in this scenario.