الفهرس 
Anatomy and Physiology of brainstemOnly 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
B
rain death is the irreversible cessation of all functions of the entire brain, including the brain stem. rain death occurs when the lower brain herniates through the skull onto the brainstem and pons, cutting off the blood supply to the brain. Diffuse cerebral edema and hemorrhage contribute to this herniation. There is no medical intervention to reverse this process, and brain death quickly follows.
Upon verification of herniation by cerebral flow studies, brain death criteria tests are initiated by the physicians and are regulated by state and federal guidelines. Families facing brain death verification and organ donation need a great deal of emotional support. After herniation, ICP values return to baseline normal. Many of the patient’s vital signs also return to normal.
Vasopressor therapy may be reduced or halted, and sedation drugs are ceased so as not to interfere with brain death testing. After determination of brain death, if organ transplantation is being pursued, the patient undergoes a series of tissue and blood typing tests, and the medical focus shifts to optimal organ perfusion and oxygenation.
Families offering a loved-one’s organs for donation need emotional support during this phase because even though their loved one is dead, machines and medications continue to keep the lungs breathing and the heart beating. These families are not afforded the kind of closure that comes from holding their loved one and saying goodbye after the heart stops.
Organ donation is process of removal and transplantation of viable organs from donor to recipient. Recipients are matched with donor organ in order to reduce recipient’s rejection of the new organ.
Organ transplantation is truly one of the miracles of modern medicine, saving the lives of many patients and improving the quality of life for many more. Given the ever-increasing gap between the number of organs needed and the supply, clinicians have an ethical obligation to help ensure that the desires of people who want to donate organs are respected.
Organ donation process is done by identifying the donor, obtaining consent from the legal next of kin or legal power of attorney as consent forms are read, signed, and witnessed, evaluating and maintaining potential donor for suitability and stability, then recovering organ donor in an operating room of the hospital by the surgery team responsible for the transplant.
The management protocols of the brain-dead organ donor are based more often on experience than on results from clinical research. Thus, a wide range of measures are being practiced but essen¬tially, most of them are based on correcting the imbalances found on close monitoring including ECG, invasive blood pressure monitoring as well as monitoring of central venous pressure, temperature and urinary output.
The maintenance of adequate tissue oxygenation is also the prime goal of intra¬operative management. Hemodynamic stability should be restricted when the systolic blood pressure exceeds 100 to 120 mmHg, in order to prevent pulmonary edema.
Complications occurring in the care of the brain-dead organ donor are: hypotension, multiple transfusion requirements, diabetes insipidus, disseminated intravascular coagulation, arrhythmias, cardiac-arrest, pulmonary edema, hypoxia, acidosis, seizures, and hypo¬thermia.
Intraoperatively, it is recommended to use neuromuscular blocking agents to avoid reflex neuromuscular activity, facilitate surgical exposure and avoid histamine releasing agents.
Organ preservation involves both monitoring and maintaining physiologic values within set parameters to avoid damage and maintain organ function. These parameters include blood pressure, respiratory rate, and fluid and electrolyte status. Function and levels can be maintained through administration of medications such as corticosteroids and thyroid hormones, as well as through adjustments to ventilator settings and fluid administration to maintain respiratory rate and electrolyte balance.