Review Question - QID 106354

This patient who has developed hypotension and is exhibiting signs of poor perfusion following myocardial infarction is likely suffering from cardiogenic shock. Pulmonary artery (PA) catheterization in cardiogenic shock typically reveals elevated RAP, elevated PAWP, decreased CO, and elevated SVR.

PA catheterization (also called Swan Ganz catheterization) can be used to evaluate the hemodynamic status of critically ill patients. Insertion of the PA catheter allows for direct measurement of RAP, right ventricular pressure, PAP, and indirect assessment of left atrial pressure, left ventricular end diastolic pressure, CO, and SVR. While prospective trials have failed to demonstrate replicable benefits in clinical outcomes, PA catheterization remains useful to characterize the hemodynamic profile of selected patients in shock.

Danchin et al. review acute myocardial infarction, and report that cardiogenic shock occurs in approximately 7% of people admitted to the hospital for acute myocardial infarction. It is usually a result of left ventricular infarction, but may also be caused by cardiac structural defects, such as mitral valve regurgitation, ventricular septal rupture, or cardiac tamponade.

Shah et al. performed a meta-analysis of randomized controlled trials evaluating PA catheter use and report that its use did not change overall mortality or days in hospital. They recommend further disease-specific use of PA catheter as well as alternative clinical end points to evaluate.

Illustration A demonstrates the wave forms seen in various anatomical locations that are evaluated using the PA catheter.

Illustration B demonstrates the territory of the RCA, LCA, area 2 (which represents an anterior wall MI) and vessel 1 (a branch of the left coronary artery)

Incorrect answers:
Answer 1: This is the hemodynamic profile of hypovolemic shock.
Answer 3: This is the hemodynamic profile of neurogenic shock.
Answer 4: This is the hemodynamic profile of early septic shock.
Answer 5: This hemodynamic profile can be seen in shock caused by reduction in the right-ventricular (RV) cardiac output (e.g., acute RV infarct or massive pulmonary embolism) but would not be expected in cardiogenic shock owing to a large anterior wall myocardial infarction.