Vasoplegia in Cardiac Surgery

Vasoplegia

Vasoplegia is a type fo distributive shock that follows cardiac surgery in up to 25% of cases. This leads to prolonged ICU stays, renal fialure, and increased mortality. Catecholamine resistant vasoplegia can be lethal with mortality rates approaching 25%. Vasoplegia can also exist in septic shock, end stage liver disease, and glucocorticoid deficiency.

Risk Factors

• Preoperative ACEi
• Higher comorbid disease burden
• Low preop EF
• Vasopressor support before and/or during CPB
• Warmer core temperature on CPB
• Long cross clamp time

Criteria

• MAP < 65 with an index of > 2.2

Physiology Simplified

Specific Effect of H2S and NO

Treatment Goals

• Restore and Maintain MAP
  • Vasopressors
  • Inhibit vasodilatory mediators
    • Methylene blue vs Hydroxocobalamin
  • Goal directed fluid admin
• Improve Tissue Perfusion
  • Fluids
  • Inotropes
  • Mechanical Support
• Prevent End Organ Damage
  • Anemia treatment
  • Assess renal, respiratory and cardiac function
• Identify and Treat Causes
  • Immune suppression
    • Steroids
    • Histamine blockers
    • Ascorbic acid/Thiamine
  • Assess other factors
    • Acidosis
    • Hypovolemia
    • Cardiogenic Shock
    • Sepsis
    • Medication/Transfusion Reaction
    • Anaphylaxis
    • Adrenal/Thyroid Crisis

Treatment Regimen

This is in order for the most part. I would recommend angiotensin II or vaso before epinephrine if the cardiac function is okay.

• Norepinephrine (0.02-0.5mcg/kg/min)
• Vasopressin (0.02-0.1un/min)
• Epinephrine (0.01-0.2mcg/kg/min)
• Angiotensin II (5-40ng/kg/min)
• Methylene Blue (1-2mg/kg bolus in 15min +/- 0.5-1mg/kg/hr infusion)
• Hydroxocobalamin (5g bolus over 15min can repeat x1)
• Hydrocortisone (50mg q6h or 100mg q8hr)
• Ascorbic acid (6g daily in divided doses per pharmacy)
• Thiamine (400 mg daily)
• Diphenhydramine (25-50mg q4-6h max 400mg in 24hr)

Comparison Between Methylene Blue and Hydroxocobalamin

A small sample size study showed no difference between the two treatment options when faced with vasoplegia status post cardiac bypass.

Link to Article

Summary