What are the recommendations for administering dopamine, specifically regarding bolusing (administering a large dose at once) versus continuous infusion?

Dopamine Administration: Continuous Infusion Only, No Bolus Dosing

Dopamine should never be administered as a bolus dose but should only be given as a continuous infusion with careful titration based on hemodynamic response and clinical context. 1, 2

Administration Guidelines for Dopamine

Dosing Strategy

• Dopamine is administered exclusively as a continuous infusion without bolus dosing 1
• Dosing ranges based on desired effects:
  • <3 μg/kg/min: Primarily renal effects (dopaminergic receptor stimulation)
  • 3-5 μg/kg/min: Inotropic effects (β-adrenergic stimulation)

  • 5 μg/kg/min: Vasopressor effects (α-adrenergic stimulation) 1

Administration Protocol

1. Begin infusion at 2-5 μg/kg/min in patients likely to respond to modest increments of heart force and renal perfusion 2
2. For more seriously ill patients, start at 5 μg/kg/min and increase gradually in 5-10 μg/kg/min increments up to 20-50 μg/kg/min as needed 2
3. Infuse into a large vein (preferably antecubital fossa) to prevent extravasation 2
4. Use an infusion pump, preferably volumetric, for precise control 2
5. Monitor continuously for:
   • Blood pressure
   • Heart rate
   • Urine output
   • Signs of tissue perfusion 1, 2

Clinical Considerations and Limitations

Hemodynamic Effects

• At higher doses (>5 μg/kg/min), dopamine increases cardiac output but also increases:
  • Heart rate
  • Risk of arrhythmias
  • Pulmonary wedge pressure 3, 4
• Dopamine's effects may diminish over time during prolonged infusions due to norepinephrine depletion 4

Adverse Effects

• Tachycardia and arrhythmias, particularly at higher doses 1, 3
• May increase myocardial ischemia 1
• Can cause hypoxemia (monitor arterial oxygen saturation) 1
• Risk of digital ischemia with higher doses 5
• Extravasation can cause tissue necrosis and sloughing 2

Important Cautions

• Dopamine is no longer recommended as first-line therapy in septic shock due to higher rates of cardiac arrhythmias 5
• Use with caution in patients with heart rate >100 bpm 1
• Monitor for diminishing urine flow, which may indicate need for dose reduction 2
• When discontinuing, gradually decrease the dose while expanding blood volume with IV fluids to prevent hypotension 2

Comparison with Other Inotropes

• Dobutamine may be preferred over dopamine for sustained inotropic support as it:

  • Maintains more stable hemodynamic effects during prolonged infusion 4
  • Causes less increase in pulmonary wedge pressure 3
  • Produces fewer arrhythmias at equivalent inotropic doses 3

• For patients on beta-blockers, consider milrinone instead of dopamine, as its cellular site of action is distal to beta-adrenergic receptors 1

Weaning Protocol

• When discontinuing dopamine infusion, gradually taper the dose rather than abrupt cessation
• Simultaneously optimize volume status to prevent rebound hypotension 2
• Consider transitioning to oral therapies for long-term management of underlying conditions

Remember that dopamine administration requires close monitoring and should be used judiciously, with careful consideration of the patient's underlying condition and hemodynamic status.