Obstructive shock statement as given in the material?

• A. It results from decreased myocardial contractility
• B. It is associated with obstruction of the great vessels or the heart; embolism and tamponade are examples
• C. It is caused by widespread vasodilation without obstruction
• D. It occurs due to blood loss

Answer: (B)

Obstructive shock happens when a physical blockage prevents blood from flowing forward through the heart or great vessels, causing a drop in effective cardiac output. The statement that fits this is about obstruction of the great vessels or the heart, with embolism and tamponade as classic examples. A pulmonary embolism blocks blood flow in the pulmonary arteries, increasing pressure on the right heart and reducing left-sided filling, which lowers output. Cardiac tamponade compresses the heart so it can’t fill properly, also cutting stroke volume and cardiac output. Other situations that cause shock by obstructing flow include tension pneumothorax, which also impairs filling and venous return.

This differs from other shock types. When the problem is decreased myocardial contractility, that’s a cardiogenic issue—pumping weakness rather than an obstruction. Widespread vasodilation without obstruction describes distributive shock, where vascular tone drops and systemic resistance is lost. Blood loss causes hypovolemic shock, where the circulating volume is reduced. In obstructive shock, the key feature is a physical blockage that limits blood flow, not a primary problem with pump strength, volume, or vessel tone.