Final answer:
c. fluid and protein shift out of the vascular compartment Decreased blood pressure following a large burn area is mainly due to a fluid and protein shift out of the vascular compartment, leading to hypovolemia. The body's compensatory mechanisms, such as vasoconstriction and increased heart rate, may not be sufficient to maintain blood pressure, and intravenous fluid replacement is often required for treatment.
Step-by-step explanation:
A large burn area predisposes to decreased blood pressure primarily because fluid and protein shift out of the vascular compartment. This condition, known as hypovolemia, occurs due to the loss of plasma from damaged blood vessels into the surrounding tissues, which in turn reduce the overall blood volume. The body's compensatory mechanisms, such as baroreceptor signaling, attempt to restore blood pressure by triggering vasoconstriction and increasing heart rate and strength of contractions. Nevertheless, due to the significant fluid and protein loss in severe burns, these compensatory mechanisms might not be sufficient to maintain normal blood pressure.Under normal conditions, hypovolemia, a low blood volume state, could also be triggered by dehydration, bleeding, vomiting, or certain medications.
However, severe burns pose a unique challenge as they cause not just fluid loss but also a loss of proteins, which are crucial for maintaining oncotic pressure within the vessels. This loss of oncotic pressure exacerbates the fluid shift out of the vessels.Treatment for hypovolemia typically includes intravenous fluid replacement to address the lost volume and help stabilize blood pressure. However, in the immediate aftermath of a burn, the body's positive feedback mechanisms attempt to prevent further injury through processes like blood clotting, but these cannot compensate for the large-scale fluid shift caused by the burn.