What is the management of cardiogenic shock?

Management of Cardiogenic Shock

Cardiogenic shock requires immediate intervention with a structured ABCDE approach, including hemodynamic stabilization with inotropes and vasopressors, followed by urgent revascularization when indicated, and consideration of mechanical circulatory support for refractory cases. 1

Definition and Diagnosis

Cardiogenic shock is characterized by:

• Hypotension (SBP <90 mmHg) despite adequate filling status
• Signs of hypoperfusion
• Hemodynamic criteria: cardiac index <2.2 L/min/m², pulmonary capillary wedge pressure >15 mmHg 1

Diagnostic approach:

• Immediate Doppler echocardiography to assess ventricular/valvular function and detect mechanical complications
• Invasive blood pressure monitoring with arterial line
• Consider pulmonary artery catheterization to guide management 1

Initial Management

1. Respiratory Support:

   • Provide oxygen/mechanical respiratory support based on blood gases
   • Consider non-invasive positive pressure ventilation for respiratory distress (respiratory rate >25 breaths/min, SaO2 <90%)
   • Proceed to endotracheal intubation if adequate oxygenation cannot be achieved 1

2. Hemodynamic Support:

   • Vasopressors and Inotropes:
     • Norepinephrine is first-line vasopressor for arterial pressure support 1
     • Initial dose: 2-3 mL (8-12 mcg of base) per minute, then titrate to maintain systolic BP 80-100 mmHg 2
     • Maintenance dose typically 0.5-1 mL per minute (2-4 mcg of base) 2
     • Dobutamine (2-20 μg/kg/min) is the most common inotrope to increase cardiac output 1
     • For SBP <70 mmHg, add dopamine 5-15 μg/kg/min IV; if refractory, consider norepinephrine 30 μg/min IV 1
     • Levosimendan or phosphodiesterase-3 inhibitors (milrinone) may be considered in specific cases 1

3. Coronary Revascularization:

   • Immediate PCI is indicated when coronary anatomy is suitable 1
   • This is critical for shock due to acute myocardial infarction 3

Target Parameters

Aim for the following targets:

• Cardiac index ≥2.2 L/min/m²
• Mixed venous oxygen saturation ≥70%
• Mean arterial pressure ≥70 mmHg
• Urine output >30 mL/h
• Lactate clearance 1

Mechanical Circulatory Support (MCS)

Consider MCS when:

• End-organ function cannot be maintained with pharmacologic therapy
• Patient is not rapidly responding to initial measures 1

Options include:

• Venoarterial extracorporeal membrane oxygenation (VA-ECMO)
• Transvalvular axial flow pump (Impella)
• Combination therapy (ECPELLA) 4

Note: Routine use of intra-aortic balloon pump is not recommended based on current evidence 1

Multidisciplinary Approach

Management by a specialized shock team is recommended, including:

• Heart failure specialists
• Critical care specialists
• Interventional cardiologists
• Cardiac surgeons 1

Special Considerations

• Older adults may present atypically and have higher mortality when mechanically ventilated 1
• Patient wishes regarding mechanical ventilation should be considered before initiating invasive ventilation 1
• Recognize the high mortality risk (50-80%) and consider early escalation of care 1, 3
• Avoid excessive vasopressors which may increase myocardial oxygen demand and worsen ischemia 1
• When administering norepinephrine, use a central venous catheter and gradually taper to avoid abrupt withdrawal 2

Pitfalls to Avoid

• Delaying diagnosis and treatment (mortality increases with time to intervention)
• Missing occult blood volume depletion (central venous pressure monitoring can help detect this) 2
• Failing to identify and address the underlying cause of shock
• Overlooking the transition from hemodynamic shock to treatment-resistant hemometabolic shock 5
• Delaying mechanical support when pharmacologic therapy is insufficient 4