NHA Phlebotomy Certification Practice Exam

What can prolonged tourniquet application cause?

1. Edema

2. Hemolysis

3. Hemoconcentration

4. Both B and C

The correct answer is: Both B and C

Prolonged tourniquet application can lead to significant changes in the blood composition and characteristics due to restricted blood flow. When a tourniquet is left on for an extended period, two main phenomena occur: hemolysis and hemoconcentration. Hemolysis is the destruction of red blood cells, which can occur when the red blood cells are subjected to stress from prolonged pressure within a confined space. This can release hemoglobin into the plasma, affecting lab results, particularly in tests measuring substances that rely on an intact red blood cell population. Hemoconcentration refers to the increased concentration of blood components such as proteins, electrolytes, and cells that occurs when plasma volume decreases as a result of prolonged tourniquet application. The restricted blood flow causes fluid from the vascular space to shift, resulting in a higher proportion of cells and solutes in the remaining blood. Considering these effects, it is clear that both hemolysis and hemoconcentration are potential consequences of prolonged tourniquet use, making the choice including both options correct. Ensuring that tourniquets are applied for no longer than necessary is a crucial practice to avoid these complications in phlebotomy.