What is the recommended dosing of noradrenaline (norepinephrine) for vasoplegia in pediatric patients?

Noradrenaline (Norepinephrine) Dosing for Vasoplegia in Pediatric Patients

For pediatric vasoplegia, noradrenaline should be initiated at 0.05-0.1 μg/kg/min and titrated up to 0.15 μg/kg/min based on hemodynamic response, with early initiation recommended for improved outcomes in children with vasoplegic shock.

Initial Dosing and Administration

• Starting dose: 0.05-0.1 μg/kg/min 1
• Maintenance dose range: 0.05-0.15 μg/kg/min 2, 1
• Maximum dose: Can be titrated higher based on clinical response, but typical effective dose is around 0.143 μg/kg/min in pediatric patients 2
• Administration route: Preferably via central venous access, though peripheral administration is acceptable in emergency situations 1

Titration Guidelines

• Titrate to achieve:

  • Age-appropriate mean arterial pressure (MAP)
  • Adequate diastolic blood pressure (DBP) for organ perfusion
  • Clinical signs of improved perfusion
  • Adequate urine output (>1 mL/kg/hr)

• Monitor for:

  • Improvement in MAP and DBP
  • Urine output (significant improvement has been demonstrated at 0.143 μg/kg/min) 2
  • Skin perfusion and capillary refill
  • Heart rate response

Clinical Considerations

Pathophysiology and Mechanism

Vasoplegia in pediatrics involves multiple mechanisms including:

• G protein-coupled receptor desensitization
• Altered second messenger pathways
• Increased nitric oxide production
• Critical illness-related corticosteroid insufficiency 3

Monitoring Parameters

• Continuous blood pressure monitoring
• Heart rate and ECG
• Urine output
• Clinical perfusion markers (capillary refill, skin temperature, mental status)
• Lactate levels
• Central venous oxygen saturation (if available)

Combination Therapy

• For refractory vasoplegia, consider adding:
  • Vasopressin as a second-line agent (has shown benefits in adult studies) 4
  • Hydrocortisone if suspected adrenal insufficiency
  • Methylene blue may be considered in severe cases unresponsive to conventional vasopressors 5

Special Considerations

Fluid Management

• Implement a restricted fluid bolus strategy (10 mL/kg over 20-30 min) with early initiation of norepinephrine 1
• Assess fluid responsiveness before large volume resuscitation
• Early norepinephrine has been shown to improve urine output in mechanically ventilated children receiving sedative and analgesic infusions 2

Septic Myocardial Dysfunction

• Norepinephrine may be beneficial as an initial agent in septic myocardial dysfunction to:
  • Maintain adequate coronary perfusion
  • Support diastolic blood pressure
  • Provide some inotropy while minimizing tachycardia 1
• For severe myocardial dysfunction, consider adding epinephrine or dobutamine

Practical Administration Tips

• Prepare in a concentration appropriate for pediatric patients
• Use weight-based calculations for all dosing
• Ensure accurate pump settings and regular line checks
• Avoid abrupt discontinuation - taper gradually when hemodynamic stability is achieved

Cautions

• Monitor for digital ischemia, especially with higher doses
• Watch for tachyarrhythmias
• Be aware of potential drug interactions with sedatives and analgesics
• Consider the impact on splanchnic perfusion with higher doses

The early use of norepinephrine in pediatric vasoplegia has demonstrated improvements in mean arterial pressure and urine output, particularly in reversing vasoplegia induced by sedative and analgesic medications 2.