What is the recommended starting dose of vasopressin for septic shock in a 10 kg child?

Vasopressin Dosing for Septic Shock in a 10 kg Child

For a 10 kg child with septic shock, the recommended starting dose of vasopressin is 0.0003-0.0005 units/kg/min (0.003-0.005 units/min), which should be added when high-dose catecholamines are required. 1, 2

Initial Management of Septic Shock in Children

Before considering vasopressin, follow this stepwise approach:

1. Initial fluid resuscitation:

   • Administer 20 mL/kg isotonic crystalloid boluses
   • May require up to 40-60 mL/kg in the first hour
   • Monitor for signs of fluid overload (hepatomegaly, rales) 1

2. First-line vasoactive support (if shock persists after fluid resuscitation):

   • For cold shock: Epinephrine (0.05-0.3 μg/kg/min)
   • For warm shock: Norepinephrine
   • Avoid dopamine as first-line agent 1

Vasopressin Therapy

When to add vasopressin:

• Add vasopressin when high-dose catecholamines are required 1, 2
• No specific consensus on the optimal threshold for initiating vasopressin 1

Dosing considerations:

• Starting dose: 0.0003-0.0005 units/kg/min (0.003-0.005 units/min for 10 kg child)
• Maximum dose: 0.002 units/kg/min (0.02 units/min for 10 kg child)
• Doses higher than 0.002 units/kg/min may increase risk of adverse effects 3

Physiologic rationale:

• Children with septic shock may have inappropriately low vasopressin levels contributing to vasodilation 4
• Vasopressin works through different receptor mechanisms than catecholamines, making it effective when catecholamine resistance develops 5

Monitoring During Vasopressin Therapy

• Closely monitor:
  • Blood pressure
  • Heart rate
  • Urine output
  • Peripheral perfusion
  • Serum sodium (risk of hyponatremia)
  • Signs of tissue ischemia (skin, mesenteric, cardiac) 3

Important Caveats

• Potential adverse effects: Decreased cardiac output, mesenteric ischemia, skin necrosis, hyponatremia, and thrombocytopenia 3
• Cardiac dysfunction: Use with caution in patients with myocardial dysfunction as vasopressin may reduce cardiac output 3, 5
• Duration: Limited data on prolonged use in pediatric patients; most studies evaluated short-term infusions 3

Therapeutic Goals

• Normal perfusion (capillary refill ≤2 seconds)
• Age-appropriate heart rate
• Warm extremities
• Urine output >1 mL/kg/h
• Normal mental status
• ScvO₂ >70%
• Cardiac index >3.3 and <6.0 L/min/m² 1

Vasopressin should be considered as an adjunctive therapy rather than first-line treatment for pediatric septic shock, with the goal of improving mortality and morbidity outcomes through enhanced hemodynamic stability when conventional catecholamine therapy is insufficient.