الصدمة القلبية

Definition

Cardiogenic shock is organ hypoperfusion because the heart cannot pump enough, not because blood volume is low.

Causes

• Large left ventricular MI (most common)
• MI complications: papillary muscle or septal rupture
• Myocarditis, severe arrhythmias, end-stage heart failure

Signs

• Systolic BP below 90 or needing drugs to support it
• Cold, mottled extremities and confusion
• Urine below 0.5 mL/kg/h
• Lung crackles and a raised lactate

Telling it apart

• Hypovolaemia: clear lungs and flat neck veins
• Cardiogenic shock: pulmonary congestion and high filling pressures

Treatment

• Reopen the artery as fast as possible in MI
• Inotropes such as dobutamine, or vasopressors such as noradrenaline
• Mechanical circulatory support in severe cases
• Fluids cautiously and only without congestion

Nursing care

• Continuous BP (often arterial line), rhythm, SpO2 and hourly urine output
• Reduce myocardial oxygen demand: rest and analgesia
• Watch drug side effects such as arrhythmias and limb ischaemia

Exam point

A large anterior MI with hypotension, crackles and cold limbs is cardiogenic shock, and large fluid volumes worsen pulmonary oedema.