## Hemodynamic Classification of Shock **Key Point:** Cardiogenic shock is defined by reduced cardiac output (CO) with elevated systemic vascular resistance (SVR) as a compensatory mechanism. ### Hemodynamic Parameters in Shock States | Shock Type | Cardiac Output | SVR | CVP/PAWP | Mechanism | |---|---|---|---|---| | **Cardiogenic** | ↓ | ↑ | ↑ | Pump failure | | Hypovolemic | ↓ | ↑ | ↓ | Volume depletion | | Septic (early) | ↑ | ↓ | ↓ | Vasodilation | | Anaphylactic | ↓ | ↓ | ↓ | Vasodilation + myocardial depression | | Obstructive | ↓ | ↑ | ↑ | Mechanical obstruction | **High-Yield:** The pathognomonic finding in cardiogenic shock is the combination of: 1. Low cardiac output (CI < 2.2 L/min/m²) 2. High SVR (> 1200 dyne·s·cm⁻⁵) 3. Elevated pulmonary capillary wedge pressure (PCWP > 18 mmHg) **Clinical Pearl:** This hemodynamic profile reflects the heart's inability to pump effectively, triggering sympathetic compensation (vasoconstriction) in an attempt to maintain perfusion pressure—but this worsens myocardial oxygen demand and afterload, creating a vicious cycle. **Mnemonic:** **CASE** — Cardiogenic = Decreased output + elevated SVR; Anaphylactic = low output + low SVR; Septic = high output + low SVR (early); Exsanguinating = low output + low SVR. 
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