A 52-year-old man with acute myocardial infarction develops cardiogenic shock. Which of the following is NOT a characteristic feature of cardiogenic shock?

Explanation

## Cardiogenic Shock: Pathophysiology and Features ### Definition and Hemodynamics Cardiogenic shock occurs when the heart fails to maintain adequate cardiac output to perfuse vital organs, typically defined as cardiac index <2.2 L/min/m² despite adequate or elevated filling pressures. ### Characteristic Hemodynamic Profile | Feature | Cardiogenic Shock | Septic Shock | |---------|-------------------|---------------| | Cardiac Output | ↓ Decreased | ↑ Increased (early) | | SVR | ↑ Increased | ↓ Decreased | | PCWP | ↑ Elevated | Normal or ↓ | | SvO₂ | ↓ Decreased | ↑ Increased | | Skin | Cold, clammy | Warm, flushed | **Key Point:** In cardiogenic shock, the heart cannot pump effectively, leading to: 1. **Decreased cardiac output** → reduced organ perfusion 2. **Increased SVR** → compensatory vasoconstriction to maintain blood pressure 3. **Elevated PCWP** → pulmonary edema (backward failure) 4. **Decreased SvO₂** → tissues extract more oxygen due to low flow ### Why Each Option Fits or Doesn't Fit **Correct features of cardiogenic shock:** - **Increased SVR** — compensatory sympathetic activation narrows vessels to maintain BP - **Decreased CO with elevated PCWP** — hallmark finding; fluid backs up into lungs - **Decreased SvO₂** — low cardiac output forces tissues to extract more O₂, reducing venous saturation **Incorrect feature (the answer):** - **Decreased SVR with warm peripheries** — this is the pattern of **septic shock** (distributive), NOT cardiogenic shock. Sepsis causes vasodilation and warm, flushed skin despite hypotension. **High-Yield:** Cardiogenic shock = **cold shock** (cold peripheries, high SVR). Septic shock = **warm shock** (warm peripheries, low SVR). This distinction is clinically critical for diagnosis and management. **Clinical Pearl:** The combination of hypotension + pulmonary edema + cold extremities is pathognomonic for cardiogenic shock and mandates urgent revascularization (PCI/CABG) or mechanical support (IABP, VAD). **Mnemonic:** **COLD Cardiogenic** — Cardiac failure, Output low, Low SvO₂, Decreased peripheries.