Management of Cardiogenic Shock
The management of cardiogenic shock requires immediate hemodynamic stabilization with norepinephrine as first-line vasopressor, dobutamine for inotropic support, and early consideration of mechanical circulatory support when pharmacological measures are insufficient. 1
Definition and Initial Assessment
Cardiogenic shock is defined as:
- 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
Immediate Diagnostic Steps:
- Immediate Doppler echocardiography to assess ventricular and valvular functions, loading conditions, and detect mechanical complications 1
- Invasive blood pressure monitoring with arterial line 1
- Consider pulmonary artery catheter placement to define hemodynamic subsets and guide management 1
Pharmacological Management
Vasopressor Support:
- Norepinephrine is the first-line vasopressor when arterial pressure support is needed 1
- Initial dose of 2-3 mL (8-12 mcg of base) per minute, then adjust to maintain MAP ≥70 mmHg 1, 2
- Average maintenance dose ranges from 0.5-1 mL per minute (2-4 mcg of base) 2
- In previously hypertensive patients, raise blood pressure no higher than 40 mmHg below preexisting systolic pressure 2
Inotropic Support:
- Dobutamine (2-20 μg/kg/min) is the most commonly used inotropic agent to increase cardiac output 1
- Levosimendan may be considered as an alternative or in combination with vasopressors, especially in patients on beta-blockers 1, 3
- Phosphodiesterase-3 inhibitors (e.g., milrinone) may be considered, especially in non-ischemic patients 1
Important Cautions:
- Avoid beta-blockers or calcium channel blockers in the acute setting as they may worsen cardiac failure 1
- Be cautious with fluid administration, especially in patients with elevated filling pressures 1
- Avoid excessive vasopressors which may increase myocardial oxygen demand 1
Mechanical Circulatory Support (MCS)
Consider temporary MCS when end-organ function cannot be maintained by pharmacologic means 1
Options include:
Routine use of intra-aortic balloon pump is not recommended based on the IABP-SHOCK II trial 1, 4
Consider transfer to centers with MCS capabilities if not rapidly responding to initial measures 1
Monitoring and Target Parameters
Target parameters for management include:
- 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
Special Considerations
- Consider non-invasive positive pressure ventilation for respiratory distress in non-intubated patients 1, 5
- Implement positive pressure ventilation in intubated patients to improve gas exchange and potentially improve LV hemodynamics 1
- Recognize the high mortality risk (50-80%) and consider early escalation of care when appropriate 1, 3
- Older adults may present with atypical symptoms and have higher mortality risk with mechanical ventilation 1
- Consider patient wishes regarding mechanical ventilation before initiation of invasive ventilation 1
Structured Approach to Management
A structured ABCDE approach is recommended 5:
- Airway: Secure as needed
- Breathing: Address respiratory failure, which is common in cardiogenic shock
- Circulation: Restore with vasopressors and inotropes
- Damage control: Prevent further deterioration
- Etiologic assessment: Identify and treat underlying cause (e.g., coronary revascularization for acute myocardial infarction)
This approach helps prevent progression from hemodynamic shock to treatment-resistant hemometabolic shock, where accumulated metabolic derangements trigger a self-perpetuating cycle of worsening shock 5, 6.