During burn resuscitation, plasma proteins moving out of the intravascular space primarily contributes to which outcome?

• A. To increase blood volume
• B. To cause edema
• C. To improve oxygen delivery
• D. To raise blood pressure

Answer: (B)

When burn injury makes capillaries more permeable, plasma proteins leak into the interstitial space. Losing these proteins lowers intravascular oncotic pressure, so water is drawn out of vessels into the interstitial tissue by osmosis. That shift causes edema (the third-spacing phenomenon), especially around the burned area. This is the primary result of proteins moving out, rather than increasing blood volume, boosting oxygen delivery, or raising blood pressure.