Hypovolemic shock caused by severe burns is primarily due to loss of which fluid component?

• A. Red blood cells
• B. Plasma
• C. Whole blood
• D. Platelets

Answer: (B)

The main idea is that severe burns cause a rapid loss of intravascular fluid due to capillary leak. When the skin is burned, capillaries become highly permeable, allowing plasma—the liquid portion of blood that contains water, electrolytes, and proteins like albumin and clotting factors—to seep into the surrounding tissue. This third-spacing of plasma reduces the circulating blood volume, decreasing venous return and cardiac output, which leads to hypovolemic shock. The cellular components, such as red blood cells, platelets, and whole blood, largely stay in the vessels initially, so the critical deficit in this burn-induced shock is plasma loss. Replenishing intravascular fluid aims to restore plasma volume and improve perfusion.