What are the indications, doses, and durations for noradrenaline (norepinephrine) versus dopamine in the management of septic shock?

Norepinephrine vs Dopamine in Septic Shock Management

Norepinephrine should be used as the first-choice vasopressor for septic shock management due to its superior efficacy and safety profile compared to dopamine, with lower mortality rates and fewer adverse events. 1, 2, 3

Indications

• Norepinephrine is indicated as first-line therapy for restoration of blood pressure in adult patients with septic shock 1, 2, 4
• Dopamine should only be used as an alternative vasopressor to norepinephrine in highly selected patients with:
  • Low risk of tachyarrhythmias 1, 2
  • Absolute or relative bradycardia 1, 5

Dosing Recommendations

Norepinephrine

• Initial dose: 0.25 mL to 0.375 mL (8-12 mcg of base) per minute 4
• Maintenance dose: 0.0625 mL to 0.125 mL (2-4 mcg of base) per minute 4
• Target MAP: 65 mmHg initially 2, 6
• Administration route: Must be administered via central venous access 2

Dopamine

• Used for hemodynamic imbalances in septic shock when norepinephrine is contraindicated 7
• Doses vary based on desired effect:
  • Low doses (1-5 μg/kg/min): Primarily dopaminergic effects (renal vasodilation) 7
  • Moderate doses (5-10 μg/kg/min): Both dopaminergic and β-adrenergic effects 7
  • High doses (10-20 μg/kg/min): Predominantly α-adrenergic effects 7

Duration of Therapy

• For both agents, vasopressors should be continued until hemodynamic stability is achieved 1, 2
• Weaning should be gradual to avoid rebound hypotension 4
• Adequate fluid resuscitation should be ensured before or concurrent with vasopressor initiation 1, 2
• Great effort should be directed toward weaning vasopressors with continuing fluid resuscitation 1

Comparative Efficacy and Safety

Mortality Benefit

• Norepinephrine is associated with an 11% absolute risk reduction in mortality compared to dopamine (NNT = 9) 3
• Systematic reviews show a statistically significant superiority of norepinephrine over dopamine for 28-day or in-hospital mortality (RR: 0.91,95% CI 0.83-0.99) 8

Adverse Events

• Norepinephrine has significantly lower risk of:
  • Supraventricular arrhythmias (RR: 0.47,95% CI 0.38-0.58) 1, 3
  • Ventricular arrhythmias (RR: 0.35,95% CI 0.19-0.66) 1, 8

Hemodynamic Effects

• Norepinephrine: Increases MAP primarily through vasoconstriction with little change in heart rate 1, 6
• Dopamine: Increases MAP and cardiac output primarily through increased stroke volume and heart rate 1, 7

Monitoring Requirements

• Arterial catheter placement is recommended for all patients requiring vasopressors as soon as practical 2, 6
• Continuous monitoring of:
  • Blood pressure (arterial line preferred) 2
  • Heart rate and rhythm 2
  • Urine output 1
  • Mental status 1
  • Peripheral perfusion 1
  • Serum lactate levels 2

Management Algorithm for Septic Shock

1. First-line: Norepinephrine with target MAP of 65 mmHg 1, 2
2. If target MAP not achieved with maximum norepinephrine doses:
   • Add vasopressin (0.01-0.03 units/minute) 2, 5
   • Or add epinephrine 1, 2
3. For persistent hypoperfusion despite adequate fluid loading and blood pressure:
   • Consider adding dobutamine 2
4. Reserve dopamine only for:
   • Patients with low risk of tachyarrhythmias 1
   • Patients with absolute or relative bradycardia 1, 5

Important Considerations and Pitfalls

• Avoid extravasation: Norepinephrine must be administered via central venous access to prevent tissue ischemia and necrosis 4
• Gradual discontinuation: Sudden cessation of norepinephrine infusion may result in marked hypotension 4
• Fluid status: Ensure adequate fluid resuscitation before or concurrent with vasopressor therapy 1, 2
• Avoid dopamine for renal protection: Low-dose dopamine for renal protection is strongly discouraged 2
• Practice patterns: Despite guidelines, dopamine continues to be used in some settings (particularly by cardiologists, in Southern US, at non-teaching hospitals), representing potential targets for quality improvement 9