What is the treatment for distributive shock?

Treatment of Distributive Shock

In distributive shock, norepinephrine is recommended as the initial vasoactive drug after appropriate fluid resuscitation. 1

Initial Assessment and Management

Fluid Resuscitation

• Begin with isotonic crystalloid fluid resuscitation (20 mL/kg bolus) 1
• Reassess patient after each fluid bolus to evaluate response and prevent fluid overload
• Ensure adequate fluid resuscitation (minimum 30 mL/kg crystalloids) before or concurrent with vasopressor initiation 2
• Ultrasound can help determine shock etiology and guide ongoing management 1

Vasopressor Therapy

1. First-line agent: Norepinephrine (0.05-0.1 μg/kg/min, titrate every 5-15 minutes) 1, 2

   • Target mean arterial pressure (MAP) of 65 mmHg 1, 2
   • Administer through central venous catheter when possible to reduce extravasation risk 2

2. Second-line agent: Vasopressin

   • Add if hypotension persists (up to 0.03 UI/min) 1, 2
   • Helps reduce norepinephrine requirements 1
   • May decrease need for renal replacement therapy 1

3. For myocardial depression in septic shock:

   • Add dobutamine to norepinephrine OR
   • Use epinephrine as a single agent 1
   • Epinephrine may be more effective than dopamine for shock resolution in pediatric patients 1

4. Dopamine considerations:

   • Only recommended in hypotensive patients with bradycardia or low risk for tachycardia 1
   • Avoid in patients at risk for arrhythmias 2

5. Phenylephrine:

   • Reserve for salvage therapy only 1

Monitoring and Titration

• Continuous arterial blood pressure monitoring is recommended 2
• Assess tissue perfusion markers:
  • Lactate levels
  • Skin perfusion
  • Mental status
  • Urine output
  • Mixed or central venous oxygen saturations 1, 2
• Monitor daily electrolytes, urea nitrogen, and creatinine during active vasopressor titration 2
• Beware of excessive vasoconstriction, which may compromise organ perfusion 2

Special Considerations

Pediatric Patients

• No specific inotrope or vasopressor has been shown superior in reducing mortality in pediatric distributive shock 1
• Selection should be tailored to each patient's physiology and adjusted as clinical status changes 1
• Evidence suggests epinephrine may be more effective than dopamine for shock resolution in the first hour 1

Complications to Monitor

• Pulmonary edema: Epinephrine increases cardiac output and causes peripheral vasoconstriction 3
• Cardiac arrhythmias: Especially in patients with coronary artery disease or cardiomyopathy 3
• Extravasation and tissue necrosis: If extravasation occurs, infiltrate area with 5-10 mg phentolamine diluted in 10-15 mL saline 2, 3
• Renal impairment: Vasopressors can constrict renal blood vessels 3

Common Pitfalls to Avoid

1. Delaying vasopressor initiation: Start norepinephrine early in septic shock, as profound and prolonged hypotension increases mortality 2

2. Inadequate fluid resuscitation: Ensure adequate volume status before or during vasopressor therapy 1, 2

3. Failure to reassess: Distributive shock physiology is dynamic and requires serial assessments to titrate vasoactive therapy 1

4. Inappropriate MAP targets: Individualize MAP goals based on patient characteristics (higher targets needed for elderly, chronic hypertension, or traumatic brain injury) 2

5. Overlooking myocardial depression: Common in septic shock; consider adding inotropic support when evidence of cardiac dysfunction exists 1