A 60 kg patient with septic shock remains hypotensive with MAP 55 mmHg despite adequate fluid resuscitation and norepinephrine titrated to 0.5 microgram/kg/min. What is the recommended next pharmacological step?
- A Double the norepinephrine dose to 1 microgram/kg/min before adding anything
- B Switch entirely to high-dose dopamine
- C Add low-dose vasopressin at a fixed infusion of 0.03 units/minute ✓
- D Add milrinone infusion
Correct answer: C. Add low-dose vasopressin at a fixed infusion of 0.03 units/minute
Explanation
When norepinephrine requirements are high (commonly cited above 0.25 to 0.5 microgram/kg/min), vasopressin is added at a fixed low dose of 0.03 units/minute rather than being titrated. The VASST trial showed this combination allows norepinephrine weaning with no excess adverse events. Relative vasopressin deficiency occurs in septic shock. Milrinone is an inodilator used in cardiogenic states with high SVR and would worsen hypotension here. Escalating norepinephrine further increases catecholamine toxicity without addressing vasopressin depletion.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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