What occurs in obstructive shock?

In obstructive shock, the main issue is that blood flow is physically impeded due to an obstruction in the cardiovascular system. This obstruction can occur in various ways, such as in cases of tension pneumothorax, cardiac tamponade, or pulmonary embolism. Each of these conditions can prevent the heart from effectively pumping blood or can block the flow of blood returning to the heart, leading to a decrease in cardiac output and inadequate tissue perfusion.

The focus in obstructive shock is on how this physical barrier affects the circulation. For example, in tension pneumothorax, air trapped in the pleural space compresses the blood vessels and the heart, consequently obstructing normal blood flow and reducing overall circulation. Similarly, in cardiac tamponade, fluid accumulation around the heart restricts its ability to contract, leading to reduced blood flow. Thus, the defining characteristic of obstructive shock is the physical obstruction that prevents normal blood flow, which is why this option is identified as correct.