What is the initial drop rate for a noradrenaline infusion?

Initial Drop Rate for Noradrenaline Infusion in 250 ml of D5

For a noradrenaline infusion prepared with 4 mg in 250 ml of D5, the initial drop rate should be 2-8 ml/hour (0.02-0.08 μg/kg/min) and titrated according to blood pressure response, targeting a MAP of 65 mmHg.

Preparation and Dosing

• Noradrenaline (norepinephrine) is the first-line vasopressor for management of hypotension in septic shock 1
• Standard preparation: 4 mg noradrenaline in 250 ml D5W = 16 μg/ml concentration 1
• Initial FDA-recommended dose: 0.02-0.04 μg/kg/min, titrated to maintain blood pressure 2

Initial Drop Rate Calculation

• For a 70 kg adult:
  • Starting dose of 0.02 μg/kg/min = 1.4 μg/min
  • With 16 μg/ml concentration, this equals approximately 5 ml/hour 1
• For severe hypotension:
  • May start at 0.05-0.1 μg/kg/min (approximately 10-20 ml/hour for 70 kg adult) 1, 3

Titration Guidelines

• Titrate to maintain mean arterial pressure (MAP) ≥65 mmHg 1
• Increase in increments of 0.02-0.05 μg/kg/min every 5-10 minutes based on response 1
• Maintenance dose typically ranges from 0.02-0.4 μg/kg/min 2, 4
• Dose severity classification 4:
  • Low dose: <0.2 μg/kg/min
  • Intermediate dose: 0.2-0.4 μg/kg/min
  • High dose: >0.4 μg/kg/min

Special Considerations

• Peripheral administration is acceptable initially while central access is being established 1
• Continuous arterial blood pressure monitoring is recommended when available 1
• Concurrent fluid resuscitation is essential (typically 30 ml/kg crystalloid in septic shock) 1
• If inadequate response to noradrenaline alone, consider adding vasopressin 0.04 units/min 1

Monitoring and Complications

• Monitor for extravasation which can cause severe tissue necrosis 2
• If extravasation occurs, infiltrate the area with 10-15 ml saline containing 5-10 mg of phentolamine 1
• Avoid abrupt discontinuation which may cause rebound hypotension 2
• Monitor for cardiac arrhythmias, especially in patients with underlying heart disease 2

Dosing Adjustments

• Obese patients may require lower weight-based doses but similar absolute doses compared to non-obese patients 5
• Elderly patients may be more sensitive to noradrenaline effects and may require lower doses 1
• Higher doses (>0.4 μg/kg/min) are associated with significantly increased mortality (40.2% vs 14.0% for low doses) 4