Why does blood pressure increase after administering norepinephrine in a trauma patient?

💡 Explanation

Norepinephrine increases blood pressure because it activates alpha-1 adrenergic receptors on blood vessels, resulting in vasoconstriction; this elevates total peripheral resistance (TPR) and blood pressure. Therefore, vasoconstriction causes the pressure increase, rather than parasympathetic effects, reduced heart rate or changes in venous return.

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