Emergency Medical Technician (EMT) Intermediate Practice Exam

In response to an injury, what happens in the serum that can lead to shock?

1. Fluid shifts occur from blood to tissues

2. Blood volume increases

3. Platelet aggregation increases

4. Oxygen transport decreases

The correct answer is: Fluid shifts occur from blood to tissues

Fluid shifts from the blood to the tissues occur in response to an injury due to factors such as inflammation and changes in vascular permeability. When tissues are injured, the body releases chemicals that cause blood vessels to become more permeable. This increased permeability allows fluid, proteins, and sometimes cells to leak out of the bloodstream and into the surrounding tissues. As a result, the volume of blood circulating in the vascular system decreases, which can lead to hypovolemia and ultimately shock. The loss of intravascular fluid can result in inadequate oxygen delivery to tissues, decreased blood pressure, and impaired organ function. This process underscores the significance of prompt recognition and intervention for patients at risk of shock due to fluid shifts. While blood volume increasing might seem beneficial, it is typically not the case in a response to injury where fluid loss and shifts are prominent. Increased platelet aggregation occurs in response to injury and can assist with clotting but does not directly lead to shock. Decreased oxygen transport may be a consequence of shock but is not the primary immediate response to injury that initiates the shock process.