Inotropic Agents for Shock Management

Introduction to Inotropes and Vasopressors

The European Society of Cardiology recommends standard dosing formulas for inotropes in shock, including dobutamine at 2-20 μg/kg/min, dopamine at 3-5 μg/kg/min (inotropic effect) or >5 μg/kg/min (vasopressor effect), norepinephrine at 0.2-1.0 μg/kg/min, and epinephrine at 0.05-0.5 μg/kg/min 1, 2, 3

Norepinephrine is the first-line vasopressor for most shock states, especially in hypotensive patients with adequate fluid resuscitation, with dosing at 0.2-1.0 μg/kg/min IV infusion, titrated to desired blood pressure 4, 5, 1, 3
The American Heart Association suggests dobutamine as the first-line inotrope for cardiogenic shock with decreased cardiac output, with dosing at 2-20 μg/kg/min IV infusion without loading dose 3, 5, 7
Dopamine dosing is effect-dependent, with 2-3 μg/kg/min for dopaminergic effects, 3-5 μg/kg/min for inotropic effects, and >5 μg/kg/min for vasopressor effects 8, 1, 7, 9

Epinephrine dosing is 0.05-0.5 μg/kg/min IV infusion, reserved for persistent hypotension despite adequate cardiac filling pressures and use of other vasoactive agents 1, 3, 2
Milrinone and enoximone are phosphodiesterase inhibitors used as second-line agents, with milrinone dosing at 25-75 μg/kg loading dose over 10-20 min, followed by 0.375-0.75 μg/kg/min infusion, and enoximone dosing at 0.5-1.0 mg/kg loading dose, followed by 5-20 μg/kg/min infusion 1, 3, 2
Levosimendan is an optional second-line agent, with an optional loading dose of 12 μg/kg over 10 minutes and maintenance at 0.1 μg/kg/min, which can be decreased to 0.05 or increased to 0.2 μg/kg/min 1, 3, 10

The Society of Critical Care Medicine recommends titrating all inotropes to the lowest effective dose to achieve adequate organ perfusion 4
Monitoring for adverse effects, including tachyarrhythmias, myocardial ischemia, and peripheral tissue ischemia, is crucial 8, 7
ECG monitoring is required during inotrope infusion due to the risk of arrhythmias 7

For cardiogenic shock, dobutamine 2-20 μg/kg/min is recommended for low cardiac output, with norepinephrine 0.2-1.0 μg/kg/min added if hypotensive 8, 1
For septic shock, norepinephrine 0.2-1.0 μg/kg/min is the first-line agent after adequate fluid resuscitation, with dobutamine 2-20 μg/kg/min added if cardiac dysfunction persists 5
For distributive shock, norepinephrine 0.2-1.0 μg/kg/min is the first-line agent, with vasopressin 0.01-0.04 units/min considered if there is an inadequate response 4, 6