Inotrope and Vasopressor Use in Shock

Introduction to Vasopressor Therapy

• The American College of Critical Care Medicine recommends norepinephrine as the first-choice vasopressor for all types of shock when fluid resuscitation fails to maintain adequate mean arterial pressure (MAP ≥65 mmHg) 1, 2, 3
• Early use of vasopressors is recommended as it reduces the incidence of organ failure 4, 5
• All patients requiring vasopressors should have an arterial catheter placed as soon as practical if resources are available 1, 6

Inotrope Indications

• The Society of Critical Care Medicine indicates that dobutamine (up to 20 μg/kg/min) is indicated when there is evidence of myocardial dysfunction with elevated cardiac filling pressures and low cardiac output 1, 3, 9
• Inotropes are indicated when signs of hypoperfusion persist despite adequate fluid resuscitation and vasopressor therapy to maintain MAP 1, 3, 9

Shock-Specific Considerations

• The European Society of Intensive Care Medicine recommends norepinephrine as the first-line vasopressor for septic shock 1, 2, 3
• If hypotension persists despite norepinephrine, vasopressin (up to 0.03 U/min) can be added to reduce norepinephrine requirements 1, 2
• In septic shock with myocardial depression, adding dobutamine or using epinephrine as a single agent may be beneficial 2

Monitoring and Titration

• Inotrope therapy should be titrated to targeted responses such as improvements in mixed venous oxygen saturation (SvO₂), myocardial function indices, and reduction in lactate levels 4, 5
• The combination of dobutamine and norepinephrine is recommended as first-line treatment in patients with low cardiac output and hypotension 4, 5

Common Pitfalls and Caveats

• The American Heart Association advises that vasopressors should not be used as a substitute for adequate fluid resuscitation in hypovolemic states 1, 2, 6
• Targeting supranormal cardiac index levels is not recommended and may be harmful 3, 8
• The optimal MAP should be individualized, as it may need to be higher in patients with pre-existing hypertension 7, 6