Examkin

Question

Difficulty: HardCardiovascular System

Match each clinical presentation of a hypotensive patient with their most likely corresponding hemodynamic profile obtained via pulmonary artery catheterization. The parameters include central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), and systemic vascular resistance (SVR).

  • A 65-year-old man with crushing chest pain, diaphoresis, and new anterior ST-segment elevationsCVP: Increased | PCWP: Increased | CI: Decreased | SVR: Increased
  • A 28-year-old man involved in a high-speed motor vehicle collision with a rigidly distended abdomen and flat neck veinsCVP: Decreased | PCWP: Decreased | CI: Decreased | SVR: Increased
  • A 72-year-old woman with a complicated urinary tract infection, fever of 39.4°C (103°F), and warm, flushed extremitiesCVP: Decreased | PCWP: Decreased | CI: Increased | SVR: Decreased
  • A 45-year-old man with sudden-onset severe dyspnea, recent deep vein thrombosis, and marked jugular venous distensionCVP: Increased | PCWP: Decreased | CI: Decreased | SVR: Increased

Answer

Cardiogenic shock (myocardial infarction) pairs with increased CVP and PCWP, decreased CI, and increased SVR. Hypovolemic shock (hemorrhage) pairs with decreased CVP, PCWP, and CI, and increased SVR. Septic shock (infection) pairs with decreased CVP, PCWP, and SVR, and increased CI. Obstructive shock (pulmonary embolism) pairs with increased CVP, decreased PCWP and CI, and increased SVR.
Each shock state has a distinct hemodynamic signature. Distributive shock is the only type with decreased SVR and increased CI. Cardiogenic shock is the only type with both increased CVP and increased PCWP. Obstructive shock is uniquely characterized by increased CVP but decreased PCWP due to the blockage occurring between the right and left heart. Hypovolemic shock is characterized by globally decreased pressures (CVP, PCWP) with decreased CI and high SVR.

Step-by-Step Solution

1
Identify the underlying type of shock based on the clinical scenario.
The scenarios describe cardiogenic shock (myocardial infarction), hypovolemic shock (hemorrhage), distributive/septic shock (infection), and obstructive shock (massive pulmonary embolism).
Accurate diagnosis of the shock etiology is required before applying physiological principles to deduce the expected hemodynamic parameters.
2
Determine the right-sided and left-sided filling pressures (CVP and PCWP).
Cardiogenic shock elevates both pressures due to left ventricular failure backing up into the lungs and right heart. Obstructive shock (PE) elevates right-sided pressures (CVP) but prevents blood from reaching the left heart (decreasing PCWP). Hypovolemic and septic shock both feature low filling pressures due to absolute or relative volume depletion.
Filling pressures distinguish cardiogenic and obstructive causes from hypovolemic and distributive causes.
3
Analyze the systemic vascular resistance (SVR) and cardiac index (CI).
Septic shock is unique for its primary severe vasodilation (low SVR) and compensatory high CI. The other three types (cardiogenic, hypovolemic, obstructive) all present with a primary low CI and a compensatory high SVR.
SVR and CI help isolate distributive shock from the other shock etiologies.

Key Concept

Hemodynamic profiles of the major types of shock (Cardiogenic, Hypovolemic, Distributive, and Obstructive) as measured by pulmonary artery catheterization.
Rate this question

Topics

Cardiovascular System

More questions from this topic