Which of the following are cited as examples of obstructive shock forms?

• A. Sepsis and septic shock
• B. Hypovolemia and dehydration
• C. Myocardial infarction and aortic dissection
• D. Embolism and cardiac tamponade

Answer: (D)

Obstructive shock happens when a physical barrier blocks blood flow, either by preventing the heart from filling properly or by blocking outflow, so cardiac output drops despite available blood. A pulmonary embolism fits this because a clot in the pulmonary arteries raises right heart afterload and impairs left-sided filling, reducing overall perfusion. Cardiac tamponade fits because fluid in the pericardial space compresses the heart, especially during diastole, limiting filling and lowering stroke volume. In contrast, sepsis and dehydration cause distributive and hypovolemic shock, where the issue is not an obstruction to flow. Myocardial infarction causes pump failure (cardiogenic shock) and aortic dissection can lead to other complications, but they aren’t classic examples of obstructive shock like embolism and tamponade.