What is the management of cardiogenic shock?

Management of Cardiogenic Shock

The management of cardiogenic shock requires immediate intervention with intravenous inotropic support as first-line therapy, followed by mechanical circulatory support (MCS) when pharmacologic means fail to maintain end-organ function. 1

Initial Assessment and Diagnosis

• Clinical criteria for shock:

  • SBP <90 mm Hg for 30 minutes or requiring inotropes/vasopressors
  • Evidence of end-organ hypoperfusion
  • Lactate >2 mmol/L 1

• Hemodynamic criteria:

  • Cardiac index <1.8 L/min/m² without vasopressors/inotropes
  • Cardiac power output <0.6 W
  • Assessment of PCWP and PAPi to identify specific shock phenotype 1

• Immediate actions:

  • Perform echocardiography to assess ventricular function, valvular disease, and mechanical complications 1
  • Assess shock severity and phenotype by evaluating hemodynamic parameters 1
  • Identify predominant failure pattern (left, right, or biventricular) 1

Pharmacological Management

First-Line Therapy

• Inotropic support: Dobutamine is the first-line inotropic agent to increase cardiac output

  • Dosage: 2-20 μg/kg/min 1

• Vasopressors for blood pressure support:

  • Norepinephrine: Initial dose 2-3 mL (8-12 mcg of base) per minute, adjusted to maintain systolic BP 80-100 mmHg

    • Average maintenance dose: 0.5-1 mL per minute (2-4 mcg of base)
    • In previously hypertensive patients, raise BP no higher than 40 mmHg below preexisting systolic pressure 2

  • Epinephrine: For septic shock-associated hypotension

    • Dosing: 0.05-2 mcg/kg/min, titrated to achieve desired mean arterial pressure
    • Administer into a large vein and avoid catheter tie-in technique 3

Target Parameters

• 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)

Indications for MCS

• End-organ function cannot be maintained by pharmacologic means
• Persistent hemodynamic instability despite optimal medical therapy
• Evidence of end-organ hypoperfusion despite pharmacological support 1

Device Selection Based on Failure Pattern

1. Left ventricular failure:

   • Microaxial intravascular flow pumps (Impella) - recommended for selected patients with STEMI and severe/refractory cardiogenic shock (Class 2a, Level B-R)
   • IABP or TandemHeart (though IABP not recommended for routine use due to lack of survival benefit) 1

2. Right ventricular failure:

   • Impella RP or TandemHeart Protek-Duo 1

3. Biventricular failure:

   • Bilateral Impella pumps or VA-ECMO with LV venting
   • Note: VA-ECMO alone is not recommended for routine use due to lack of survival benefit (Class 3, Level B-R) 1

Special Considerations

• Revascularization: Consider early revascularization for ischemic causes 1

• Ventilation management:

  • Non-invasive positive pressure ventilation for respiratory distress in non-intubated patients
  • Positive pressure ventilation in intubated patients to improve gas exchange and potentially improve LV hemodynamics 1
  • Consider patient wishes regarding mechanical ventilation before initiation 1

• Older adults:

  • May present with atypical or delayed presentations
  • Higher mortality risk with mechanical ventilation 1

• Alternative inotropes:

  • Consider milrinone or levosimendan in specific situations (e.g., patients on beta-blockers) 1

Fluid Management

• Assess for occult blood volume depletion when high doses of vasopressors are required
• Central venous pressure monitoring is helpful in detecting and treating volume depletion 2
• For norepinephrine administration:
  • Degree of dilution depends on clinical fluid volume requirements
  • If large volumes of fluid are needed, use solution more dilute than 4 mcg/mL
  • If large volumes are undesirable, use concentration greater than 4 mcg/mL 2

Common Pitfalls and Caveats

• Avoid abrupt withdrawal of vasopressors - reduce gradually 2
• Avoid catheter tie-in technique as it promotes stasis and increased local concentration of vasopressors 2, 3
• Avoid veins of the leg in elderly patients or those with occlusive vascular diseases 3
• Do not delay MCS when pharmacologic therapy is insufficient - early implementation improves outcomes 1
• Do not routinely use IABP as it lacks survival benefit (Class 3, Level B-R) 1
• Always suspect and correct occult blood volume depletion when high doses of vasopressors are required 2