EMT Medical Conditions Practice Exam

Obstructive shock occurs when something blocks forward blood flow, preventing the heart from effectively delivering blood to the body's tissues. This blockade can be due to conditions like a tension pneumothorax that compresses the heart and great vessels, a massive pulmonary embolism that obstructs blood entering the lungs, or cardiac tamponade where fluid around the heart restricts its filling. Because the obstruction reduces venous return and/or outflow, cardiac output drops and tissue perfusion falls, leading to shock. Other shock types arise from different problems. Hypovolemic shock comes from a loss of circulating blood volume, septic shock from widespread infection causing systemic vasodilation, and cardiogenic shock from the heart's inability to pump effectively. The key distinction here is that obstructive shock centers on a physical blockage to blood flow, not just a volume deficit or pump failure.