Role of Adrenaline (Epinephrine) Infusion in Cardiogenic Shock
Epinephrine is not recommended as an inotrope or vasopressor in cardiogenic shock and should be restricted to use as rescue therapy in cardiac arrest only. 1
First-Line Management Approach for Cardiogenic Shock
- Initial management should include a fluid challenge (250 mL/10 min) if clinically indicated, followed by an inotropic agent if systolic blood pressure remains <90 mmHg 1
- Dobutamine is the first-line inotropic agent for increasing cardiac output in cardiogenic shock, particularly in patients with dilated, hypokinetic ventricles 2
- Dobutamine should be started at 2-3 μg/kg/min without a loading dose and titrated according to clinical response, with a maximum dose typically of 15-20 μg/kg/min 2
Vasopressor Selection in Cardiogenic Shock
- Norepinephrine is the preferred vasopressor when the combination of an inotropic agent and fluid challenge fails to restore adequate blood pressure and organ perfusion 1, 3
- Norepinephrine should be administered through a central line with a starting dose of 2-3 mL/minute (8-12 mcg/minute) to maintain systolic blood pressure 80-100 mmHg 3
- All vasopressors should be used with caution in cardiogenic shock as it is usually associated with high systemic vascular resistance and should be discontinued as soon as possible 1
Why Epinephrine Should Be Avoided
- The European Society of Cardiology explicitly states that epinephrine is not recommended as an inotrope or vasopressor in cardiogenic shock 1
- Despite its beneficial effect on myocardial contractility, epinephrine's side effects (arrhythmias and increased myocardial oxygen consumption) may be associated with increased mortality 4
- For most patients with cardiogenic shock, norepinephrine is more appropriate due to a lower risk of adverse events than other catecholamine vasopressors like epinephrine 5
Alternative Agents for Refractory Cases
- Milrinone is a phosphodiesterase-3 inhibitor that may be beneficial, especially in patients on beta-blocker therapy or with right ventricular dysfunction 3
- Levosimendan may be considered as an alternative inotrope, especially in patients on beta-blocker therapy, as its inotropic effect is independent of beta-adrenergic stimulation 1, 2
- The combination of milrinone and norepinephrine may be beneficial in patients with cardiogenic shock, as milrinone improves cardiac output by reducing afterload, while norepinephrine maintains coronary and systemic perfusion pressure 3
Monitoring Parameters
- Continuous monitoring of organ perfusion markers is essential, including urine output, lactate clearance, mental status, and mixed venous oxygen saturation 1, 3
- Invasive hemodynamic monitoring with an arterial line is recommended for all patients with cardiogenic shock 3
- Treatment targets should include SBP >90 mmHg and cardiac index >2 L/min/m² 1, 3
Important Caveats
- All inotropes should be used at the lowest possible doses for the shortest duration due to their propensity to increase myocardial oxygen demand and risk of arrhythmias 2, 3
- Mechanical circulatory support should be considered early for potentially reversible causes of acute heart failure rather than combining multiple inotropes 1
- In patients with right ventricular failure, the combination of milrinone and norepinephrine is particularly beneficial, as milrinone reduces RV afterload while norepinephrine maintains RV perfusion pressure 3