"Brain damage during bypass surgery is so common that hospital personnel refer to it as pump head. The primary cause is emboli produced during surgery from clamping the aorta and from the 'heart-lung machine.' This machine pumps blood to keep the patient alive while the heart is stopped during the operation. Unfortunately, this pump also introduces toxic gases, fat globules, and bits of plastic debris into the bloodstream of the patient under anesthesia. Once they are in the bloodstream, these particles migrate to the brain where they can clog capillaries and prevent adequate amounts of blood and oxygen from flowing to the brain. Essentially, all patients experience brain emboli during surgery and for many the damage is permanent."