Epinephrine used for obstetric hypotension primarily increases:

Epinephrine used for obstetric hypotension primarily increases:

• A. Uterine blood flow
• B. Heart rate and contractility
• C. Placental transfer of oxygen
• D. Vascular permeability

Answer: (B)

The key concept is that restoring maternal hemodynamics in obstetric hypotension relies on boosting cardiac output. Epinephrine primarily increases heart rate and contractility through beta-1 receptor stimulation in the heart. This enhances stroke volume and speed, raising overall cardiac output and mean arterial pressure, which improves perfusion to both the uterus and placenta indirectly. Although epinephrine also has alpha-adrenergic effects that can cause vasoconstriction, the critical therapeutic effect in this setting is the enhanced cardiac performance that reverses the hypotension. Uterine blood flow isn’t directly increased by epinephrine; vasoconstriction can even reduce some regional blood flow if not balanced by improved cardiac output. Placental transfer of oxygen isn’t directly augmented by epinephrine, which depends more on maternal oxygenation and placental function. Vascular permeability isn’t the primary action here either.

The key concept is that restoring maternal hemodynamics in obstetric hypotension relies on boosting cardiac output. Epinephrine primarily increases heart rate and contractility through beta-1 receptor stimulation in the heart. This enhances stroke volume and speed, raising overall cardiac output and mean arterial pressure, which improves perfusion to both the uterus and placenta indirectly. Although epinephrine also has alpha-adrenergic effects that can cause vasoconstriction, the critical therapeutic effect in this setting is the enhanced cardiac performance that reverses the hypotension.

Uterine blood flow isn’t directly increased by epinephrine; vasoconstriction can even reduce some regional blood flow if not balanced by improved cardiac output. Placental transfer of oxygen isn’t directly augmented by epinephrine, which depends more on maternal oxygenation and placental function. Vascular permeability isn’t the primary action here either.