Which drug is best for treating hypotension in the setting of severe acidemia?

Which drug is best for treating hypotension in the setting of severe acidemia?

• A. Norepinephrine
• B. Epinephrine
• C. Phenylephrine
• D. Vasopressin

Answer: (D)

In severe acidemia, responsiveness to catecholamines (which power drugs like norepinephrine, epinephrine, and phenylephrine) is reduced because acidosis impairs adrenergic receptor signaling. Vasopressin works through V1 receptors on vascular smooth muscle to cause vasoconstriction via a non-adrenergic pathway, and its effectiveness is preserved in acidemia. This makes vasopressin a more reliable option to raise systemic vascular resistance and treat hypotension when pH is severely low. It can also be used alongside catecholamines to improve overall blood pressure while potentially lowering catecholamine doses.

In severe acidemia, responsiveness to catecholamines (which power drugs like norepinephrine, epinephrine, and phenylephrine) is reduced because acidosis impairs adrenergic receptor signaling. Vasopressin works through V1 receptors on vascular smooth muscle to cause vasoconstriction via a non-adrenergic pathway, and its effectiveness is preserved in acidemia. This makes vasopressin a more reliable option to raise systemic vascular resistance and treat hypotension when pH is severely low. It can also be used alongside catecholamines to improve overall blood pressure while potentially lowering catecholamine doses.