If norepinephrine fails to achieve target MAP in septic shock, which adjunct vasopressor is commonly used?

If norepinephrine fails to achieve target MAP in septic shock, which adjunct vasopressor is commonly used?

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

Answer: (D)

When septic shock does not respond to norepinephrine enough to reach the target MAP, an adjunct vasopressor that works through a different mechanism is commonly added. Vasopressin fits this role because it is a noncatecholamine vasopressor that acts on V1 receptors to cause vigorous vasoconstriction, helping to raise systemic vascular resistance and MAP without relying on adrenergic receptors. In septic shock, endogenous vasopressin can be depleted, so supplementing it helps restore vascular tone and can reduce the required dose of norepinephrine, potentially decreasing catecholamine-related side effects. It is used as an adjunct to norepinephrine rather than a stand-alone agent, typically at a low fixed infusion rate (about 0.03 units per minute), to maintain MAP when norepinephrine alone is insufficient. Other options like dopamine, epinephrine, or phenylephrine may have more undesirable effects or be less effective in this context, whereas vasopressin specifically targets vasoconstriction via V1 receptors and supports perfusion when first-line catecholamines fall short.

When septic shock does not respond to norepinephrine enough to reach the target MAP, an adjunct vasopressor that works through a different mechanism is commonly added. Vasopressin fits this role because it is a noncatecholamine vasopressor that acts on V1 receptors to cause vigorous vasoconstriction, helping to raise systemic vascular resistance and MAP without relying on adrenergic receptors. In septic shock, endogenous vasopressin can be depleted, so supplementing it helps restore vascular tone and can reduce the required dose of norepinephrine, potentially decreasing catecholamine-related side effects. It is used as an adjunct to norepinephrine rather than a stand-alone agent, typically at a low fixed infusion rate (about 0.03 units per minute), to maintain MAP when norepinephrine alone is insufficient. Other options like dopamine, epinephrine, or phenylephrine may have more undesirable effects or be less effective in this context, whereas vasopressin specifically targets vasoconstriction via V1 receptors and supports perfusion when first-line catecholamines fall short.