Plasma exchange is a medical procedure that involves removing a patient's blood plasma, which is the liquid component of blood, and replacing it with a substitute solution. This process helps to eliminate harmful substances, such as antibodies or toxins, from the bloodstream. It is often used to treat various autoimmune diseases, certain blood disorders, and conditions like Guillain-Barré syndrome. During the procedure, blood is drawn from the patient, and a machine separates the plasma from the blood cells. The remaining blood cells are then mixed with a replacement fluid, such as saline or albumin, before being returned to the patient's body. Plasma exchange can help improve symptoms and overall health in affected individuals.