Cardiogenic shock management

Cardiogenic shock management

Cardiogenic shock management

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Pathophysiology & Diagnosis - The Failing Pump

  • Vicious Cycle: A primary cardiac insult (e.g., large MI) drastically reduces contractility, leading to a sharp ↓ in Cardiac Output (CO) and subsequent hypotension.
  • Maladaptive Compensation: The body's response-↑ sympathetic tone and ↑ Systemic Vascular Resistance (SVR)-paradoxically increases cardiac afterload and myocardial oxygen demand, which further impairs pump function and worsens ischemia.
  • Diagnosis: Based on clinical signs of hypoperfusion (cool, clammy skin; altered mental status; oliguria) and congestion (JVD, rales).
    • Hemodynamic Criteria (Invasive Monitoring):
      • Systolic BP < 90 mmHg
      • Pulmonary Capillary Wedge Pressure (PCWP) > 18 mmHg
      • Cardiac Index (CI) < 2.2 L/min/m²

⭐ The classic hemodynamic signature is a low Cardiac Index (< 2.2) with a high PCWP (> 18), differentiating it from hypovolemic or distributive shock.

Cardiogenic Shock Classification and Hemodynamic Profile

Initial Management - First-Response ABCs

  • A - Airway: Assess patency. Low threshold for endotracheal intubation in patients with altered mental status or impending respiratory collapse to reduce the work of breathing.
  • B - Breathing:
    • Administer supplemental O₂ to maintain SpO₂ > 90%.
    • Consider Non-Invasive Positive Pressure Ventilation (NIPPV) for acute pulmonary edema if the patient is alert and hemodynamically stable.
    • Proceed to mechanical ventilation if NIPPV fails or is contraindicated.
  • C - Circulation:
    • Secure 2 large-bore peripheral IVs.
    • Treat unstable arrhythmias (tachycardia/bradycardia) per ACLS.
    • ⚠️ Judicious fluid challenge: 250-500 mL isotonic crystalloid only if no signs of fluid overload (e.g., pulmonary rales).

⭐ Unlike other shock types, large-volume fluid resuscitation is harmful in cardiogenic shock as it exacerbates pulmonary edema and cardiac strain.

Chest X-ray and CT: Cardiogenic Pulmonary Edema

Pharmacotherapy - Potent Potion Push

  • Goal: Improve cardiac output (CO) & maintain mean arterial pressure (MAP) > 65 mmHg.

  • First-line therapy depends on blood pressure.

  • Key Agents:

    • Norepinephrine: α1 > β1 agonist. ↑SVR, ↑MAP. First choice in hypotension.
    • Dobutamine: β1 > β2 agonist. ↑CO, ↓SVR. Can cause hypotension. Use when BP is stable or with a pressor.
    • Milrinone: PDE-3 inhibitor. Inodilator (↑CO, ↓SVR). Useful if patient is on beta-blockers.
    • Diuretics (Furosemide): Use cautiously for pulmonary congestion if BP allows.

⭐ In cardiogenic shock with profound hypotension, norepinephrine is the initial vasopressor of choice. Dobutamine can be added once MAP is stabilized (>65 mmHg) to specifically improve cardiac contractility and output.

Common Inotropes and Vasopressors: Dosing and Half-life

Mechanical Support - The Big Guns

  • Intra-Aortic Balloon Pump (IABP):
    • Mechanism: Counter-pulsation. Inflates in diastole (↑coronary perfusion), deflates in systole (↓afterload).
    • Provides modest hemodynamic support.
    • ⚠️ CI: Significant aortic regurgitation, aortic dissection.
  • Percutaneous VADs (e.g., Impella):
    • Mechanism: Axial flow pump actively pulls blood from the left ventricle to the aorta.
    • Directly unloads the LV, providing superior support to IABP.
  • VA-ECMO (Veno-Arterial ECMO):
    • Provides full cardiopulmonary support; highest level of support.

    VA-ECMO increases LV afterload, which can worsen pulmonary edema. May require LV venting (e.g., with an Impella).

VA-ECMO with LV Venting Strategies for Cardiogenic Shock

High‑Yield Points - ⚡ Biggest Takeaways

  • Cardiogenic shock is defined by low cardiac output and high PCWP (>18 mmHg).
  • Initial stabilization may require inotropes (dobutamine) and vasopressors (norepinephrine).
  • Use IV fluids cautiously or not at all, as they can worsen pulmonary edema.
  • Definitive treatment targets the underlying cause, most commonly urgent revascularization for acute MI.
  • Intra-aortic balloon pump (IABP) can serve as a bridge to definitive therapy.
  • Avoid beta-blockers and nitrates during the acute hypotensive phase.

Practice Questions: Cardiogenic shock management

Test your understanding with these related questions

Two days after admission for myocardial infarction and subsequent coronary angioplasty, a 65-year-old man becomes distressed and diaphoretic in the cardiac intensive care unit. Suddenly he is no longer responsive. Pulse oximetry does not show a tracing. He has a history of hypertension and depression. Prior to his admission, his medication included ramipril and aripiprazole. Examination shows no carotid pulse. An ECG is shown. After beginning chest compressions, which of the following is the most appropriate step in management of the patient?

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Flashcards: Cardiogenic shock management

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Which major medical insurance plan limits patients to a network of doctors, specialists, and hospitals without requirement of referrals?_____

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Which major medical insurance plan limits patients to a network of doctors, specialists, and hospitals without requirement of referrals?_____

Exclusive provider organization (EPO)

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