What is the preferred vasopressor, epinephrine (adrenaline) or norepinephrine (noradrenaline), for managing hypotension post-return of spontaneous circulation (ROSC)?

Norepinephrine is the Preferred Vasopressor for Post-ROSC Hypotension

Norepinephrine should be used as the first-line vasopressor for managing hypotension following return of spontaneous circulation (ROSC) rather than epinephrine. 1 This recommendation is based on current evidence showing better hemodynamic stability and lower rates of rearrest with norepinephrine compared to epinephrine in the post-ROSC period.

Evidence Supporting Norepinephrine as First Choice

Clinical Outcomes

• A national survey of emergency medicine pharmacists found that norepinephrine is the first-choice vasopressor (81%) for post-ROSC hypotension in current practice, while epinephrine is preferred less frequently (17%) 1
• Patients who received epinephrine infusions after ROSC were found to be 3.28 times more likely to experience prehospital rearrest compared to those who received norepinephrine (55% vs 25%) 2
• In an adjusted regression model, the odds of experiencing refractory shock, rearrest, or death in the emergency department were 3.94 times higher in patients treated with epinephrine compared to norepinephrine 3

Hemodynamic Stability

• Epinephrine's β-adrenergic effects may increase myocardial oxygen demand, reduce subendocardial perfusion, and be proarrhythmic 4
• Early epinephrine administration post-ROSC is associated with more tachycardia (73.9%) and hypertension in the early post-resuscitation period 5

Algorithm for Vasopressor Selection Post-ROSC

1. First-line vasopressor: Norepinephrine

   • Starting dose: 0.05-0.1 μg/kg/min
   • Titrate to maintain mean arterial pressure (MAP) ≥65 mmHg
   • Maximum dose: Up to 2 μg/kg/min as needed

2. Second-line options (if inadequate response to norepinephrine):

   • Add vasopressin (0.01-0.03 U/min) to reduce norepinephrine requirements
   • Consider adding dobutamine (2.5-10 μg/kg/min) if evidence of myocardial dysfunction

3. Epinephrine considerations:

   • Reserve for specific scenarios such as bradycardic shock
   • If used, start at 0.05 μg/kg/min and titrate carefully
   • Monitor closely for tachyarrhythmias and rearrest

Special Considerations

Shock Type Assessment

• Identify the underlying shock etiology (cardiogenic, distributive, hypovolemic, or obstructive) to guide vasopressor selection 6
• For cardiogenic shock with persistent tachycardia, norepinephrine remains the preferred agent 6

Fluid Resuscitation

• Ensure adequate fluid resuscitation before or concurrent with vasopressor initiation 6
• Assess for signs of volume responsiveness before escalating vasopressor doses

Monitoring During Vasopressor Therapy

• Continuous cardiac monitoring for arrhythmias
• Frequent blood pressure measurements (preferably invasive arterial monitoring)
• Monitor for signs of end-organ perfusion (urine output, mental status, lactate clearance)

Common Pitfalls to Avoid

1. Overuse of epinephrine: The evidence suggests that epinephrine post-ROSC is associated with higher rates of rearrest and hemodynamic instability 2, 3

2. Delayed vasopressor initiation: Prompt treatment of post-ROSC hypotension is essential to maintain organ perfusion

3. Inadequate fluid resuscitation: Ensure euvolemia before or concurrent with vasopressor therapy

4. Failure to reassess: Frequently reassess the patient's hemodynamic status and adjust vasopressor therapy accordingly

In conclusion, while epinephrine is the recommended agent during cardiac arrest, norepinephrine appears to be the superior choice for managing hypotension after ROSC has been achieved, with evidence showing lower rates of rearrest and better hemodynamic stability compared to epinephrine.