During CPR, epinephrine's primary purpose is to increase vasoconstriction to improve perfusion pressures. Which option best reflects this action?

• A. Increase vasoconstriction
• B. Increase heart rate
• C. Vasodilation
• D. Decrease myocardial contractility

Answer: (A)

In CPR the main goal is to raise the perfusion pressure delivered to the heart and brain during chest compressions so ROSC is more likely. Epinephrine helps accomplish this primarily by triggering vasoconstriction through alpha-adrenergic receptors. This vasoconstriction increases systemic vascular resistance and raises the aortic diastolic pressure, which in turn boosts the coronary and cerebral perfusion pressures during compression. That enhanced perfusion pressure is what supports achieving ROSC.

Epinephrine does have beta-adrenergic effects that can increase heart rate and myocardial contractility, but those are secondary to its vasoconstrictive action in this setting and can raise myocardial oxygen demand without the same clear benefit to improving perfusion pressures. Vasodilation would do the opposite by lowering perfusion pressures, and decreasing myocardial contractility contradicts epinephrine’s beta-1 effects. So increasing vasoconstriction best reflects the primary action of epinephrine during CPR.