Can I add another vasopressor to a patient with hypotension who is already on norepinephrine (noradrenaline)?

Management of Hypotension in a Patient with MAP of 45 on Norepinephrine

Yes, you should add another vasopressor when your patient has a MAP of 45 mmHg despite being on norepinephrine. 1

Rationale for Adding a Second Vasopressor

When a patient remains hypotensive (MAP 45 mmHg) despite norepinephrine therapy, this indicates inadequate response to the first-line vasopressor and requires escalation of therapy to achieve the target MAP of 65 mmHg.

Algorithm for Vasopressor Management:

1. First-line agent: Norepinephrine

   • Recommended as the initial vasopressor of choice (strong recommendation, moderate quality evidence) 1
   • Titrate to achieve target MAP of 65 mmHg

2. Second-line options when MAP remains below target:

   • Vasopressin (preferred second agent)

     • Add at a fixed dose of 0.03 U/min (not titrated)
     • Can be added to either raise MAP or decrease norepinephrine requirements
     • Moderate quality evidence supports this approach 1

   • Epinephrine (alternative second agent)

     • Can be added to or potentially substituted for norepinephrine
     • Lower quality evidence compared to vasopressin 1

3. Third-line options:

   • Dopamine - only in highly selected patients with low risk of tachyarrhythmias or with relative bradycardia 1
   • Phenylephrine - reserved for specific situations:
     • When norepinephrine causes serious arrhythmias
     • When cardiac output is known to be high but blood pressure remains low
     • As salvage therapy when other agents have failed 1

Practical Considerations

• Ensure adequate volume status first - Hypotension may be exacerbated by hypovolemia, which should be addressed with appropriate fluid resuscitation before or concurrent with vasopressor escalation 1

• Arterial line placement - All patients requiring vasopressors should have an arterial catheter placed as soon as practical for accurate blood pressure monitoring 1

• Consider inotropic support - If there is evidence of myocardial dysfunction or persistent hypoperfusion despite adequate fluid loading and vasopressor therapy, consider adding dobutamine (up to 20 μg/kg/min) 1

• Early addition of vasopressin - Recent evidence suggests that adding vasopressin within 3 hours of starting norepinephrine may lead to faster shock resolution 2

Potential Pitfalls

• Avoid high-dose catecholamines - Excessive doses of catecholamines can lead to tachyarrhythmias, myocardial ischemia, and limb ischemia 3

• Don't use low-dose dopamine for renal protection - This practice is not supported by evidence and should be avoided (strong recommendation, high quality evidence) 1

• Don't delay second vasopressor - When MAP is significantly below target (as in this case at 45 mmHg), prompt addition of a second agent is warranted rather than continuing to increase norepinephrine to excessive doses 1

• Don't use vasopressin as initial monotherapy - Low-dose vasopressin is not recommended as the single initial vasopressor for treatment of sepsis-induced hypotension 1

By following this approach, you can optimize hemodynamic management while minimizing the risks associated with excessive catecholamine exposure in your hypotensive patient.