What are the indications to start inotropes (inotropic agents) on a patient?

From the Guidelines

Inotropes are indicated for patients with acute or chronic heart failure who have evidence of decreased cardiac output, hypotension, and end-organ hypoperfusion despite adequate fluid resuscitation, as stated in the most recent study 1.

Indications for Inotrope Therapy

The following scenarios are common indications for inotrope therapy:

• Cardiogenic shock
• Post-cardiac surgery
• Refractory heart failure
• As a bridge to more definitive therapy such as heart transplantation or mechanical circulatory support

Medications and Dosages

Specific medications and their dosages include:

• Dobutamine (starting at 2-5 mcg/kg/min) 1
• Milrinone (loading dose of 25-75 mcg/kg followed by 0.375-0.75 mcg/kg/min) 1
• Epinephrine (0.01-0.1 mcg/kg/min) 1
• Norepinephrine (0.01-3 mcg/kg/min) 1
• Dopamine (2-20 mcg/kg/min) 1

Precautions and Monitoring

Before initiating inotropes, ensure:

• Adequate volume status
• Correct electrolyte abnormalities (particularly potassium and magnesium)
• Consider echocardiography to confirm cardiac dysfunction Continuous hemodynamic monitoring is essential during inotrope therapy, including:
• Blood pressure
• Heart rate
• Urine output
• Ideally central venous pressure or pulmonary artery catheter measurements Inotropes work by increasing myocardial contractility, which improves cardiac output but at the cost of increased myocardial oxygen consumption and potential arrhythmias, as noted in 1.

From the FDA Drug Label

Dobutamine Injection, USP is indicated when parenteral therapy is necessary for inotropic support in the short-term treatment of patients with cardiac decompensation due to depressed contractility resulting either from organic heart disease or from cardiac surgical procedures The indications to start inotrope therapy on a patient are:

• Cardiac decompensation due to depressed contractility
• Organic heart disease
• Cardiac surgical procedures 2 Note that the FDA label for milrinone does not explicitly state the indications for starting inotrope therapy, but rather describes the drug's mechanism of action and effects. Therefore, the information from the dobutamine label is used to answer the question.

From the Research

Indications for Inotrope Use

The following are indications for inotrope use in patients:

• Cardiogenic shock, as inotropes are often first-line treatment in these cases 3
• Acute decompensated heart failure, where inotropes can help increase cardiac contractility 3, 4
• Arrhythmias caused by cardiogenic shock, where inotropes like milrinone and dobutamine can be used to manage the condition 5
• Low cardiac output, where inotropes can help increase cardiac contractility and improve perfusion of vital organs 4, 6

Specific Clinical Settings

Inotropes can be used in the following specific clinical settings:

• Patients with acute myocardial infarction and cardiogenic shock, where inotropes can help stabilize hemodynamic parameters 4
• Patients with renal dysfunction, where the choice of inotrope may depend on the presence of acute kidney injury (AKI) 7
• Patients with multi-organ failure, where inotropes can help improve perfusion of vital organs and prevent further deterioration 4, 6

Inotrope Selection

The selection of inotrope depends on various factors, including:

• The underlying cause of cardiogenic shock 4, 6
• The presence of renal dysfunction or AKI 7
• The patient's hemodynamic profile, including blood pressure and cardiac output 5, 4
• The potential for adverse effects, such as arrhythmias or hypotension 5, 6