Cardiogenic shock
Formal Definition
A state of inadequate tissue perfusion resulting from primary cardiac dysfunction; characterized by hypotension (SBP <90 mmHg or MAP <65 mmHg), evidence of end-organ hypoperfusion (altered mental status, oliguria, elevated lactate), and evidence of elevated filling pressures or low cardiac output; a medical emergency with mortality of 40-60% requiring urgent hemodynamic support.
How It's Used on the Ward
Cardiogenic shock or pump failure — the heart is failing to pump enough blood to keep the organs alive; requires pressors and often mechanical support.
Example
"Post-MI patient with SBP 78, lactate 8.2, urine output 10 mL/h, confused. Cardiac index 1.6 L/min/m2, PCWP elevated at 24 mmHg. Diagnosis: cardiogenic shock. Emergent Impella placement, norepinephrine started, cardiology and CT surgery consulted. Awaiting revascularization."
Clinical Context
Cardiogenic shock vs hypovolemic vs distributive: cardiogenic shock has elevated PCWP (high filling pressures, pulmonary edema), low cardiac output; hypovolemic has low PCWP; septic has low PCWP + high cardiac output (warm shock). Cause identification: MI (most common), myocarditis, cardiomyopathy, valvular catastrophe, arrhythmia. Management: oxygenate (avoid pure NRB if needing intubation), fluid (cautious — may worsen pulmonary edema), vasopressors (norepinephrine first-line), inotropes (dobutamine/milrinone if persistent), mechanical circulatory support (Impella, IABP, ECMO). Revascularization is the definitive treatment for MI-related cardiogenic shock — early PCI improves survival.