Embolism and cardiac tamponade are cited as examples of which type of shock?

• A. Septic shock
• B. Hypovolemic shock
• C. Cardiogenic shock
• D. Obstructive shock

Answer: (D)

Obstructive shock occurs when something mechanically blocks or severely restricts blood flow through the heart or great vessels, so the heart can’t fill or eject effectively even if the blood volume is normal. An embolism, such as a pulmonary embolism, can abruptly block blood flow in the pulmonary arteries and reduce left ventricular filling and cardiac output. Cardiac tamponade involves accumulation of fluid in the pericardial space that compresses the heart, preventing proper filling of the chambers and decreasing stroke volume. Both situations are classic examples of obstructive shock because the primary problem is an obstruction to circulation, not a failure of the heart’s pumping mechanism alone or a lack of volume. By contrast, septic shock is due to widespread vasodilation and capillary leak (distributive), hypovolemic shock from loss of circulating volume, and cardiogenic shock from pump failure.