Brain Death

Brain death is the loss of function of the entire cerebrum and brain stem, leading to coma, absence of spontaneous breathing and loss of all brainstem reflexes. Spinal reflexes, incl. Deep tendon reflexes, plantar flexion and evasive reflexes may be preserved. There is no recovery.

The brain death concept was developed because ventilators and medicines can get the cardiopulmonary and other body functions over time, although the whole brain activity is completely extinguished. The strategy of having brain death (d. E., The complete shutdown of the integrated function of the brain, v. A. Of the brainstem) justifies the death of a person is legally and culturally in most parts of the world accepted.

Brain death is the loss of function of the entire cerebrum and brain stem, leading to coma, absence of spontaneous breathing and loss of all brainstem reflexes. Spinal reflexes, incl. Deep tendon reflexes, plantar flexion and evasive reflexes may be preserved. There is no recovery. The brain death concept was developed because ventilators and medicines can get the cardiopulmonary and other body functions over time, although the whole brain activity is completely extinguished. The strategy of having brain death (d. E., The complete shutdown of the integrated function of the brain, v. A. Of the brainstem) justifies the death of a person is legally and culturally in most parts of the world accepted. Diagnosis Serial determination of clinical criteria apnea test Sometimes EEG, imaging of the brain vessels, or both To determine brain death, a doctor must be a known structural or metabolic cause of brain damage, and the use of potentially anesthetic or paralyzing drug, especially by the patient himself occupied, must be excluded. Hyperthermia <35 ° C must be corrected, and V. a. an EEG should be performed epilepticus status. Repeated studies of 6-24 hours are generally carried out (see Table: guidelines for brain death determination (in patients> 1 year)). The investigation includes assessment of Pupillenreaktivität assessment of oculovestibulären, oculocephalic and corneal reflexes apnea test Sometimes EEG or cerebral blood tests are used to confirm the absence of brain activity or brain blood flow and thus to provide the family members additional evidence; these tests are not generally required. They are indicated if the apnea test is hemodynamically tolerated and not only when a neurological examination is desired (eg. As the procurement of organs for transplantation to accelerate). Clinical Calculator: Mean vessel pressure (systemic or pulmonary) guidelines for brain death determination (in patients> 1 year) all 9 points must be confirmed in order to declare brain death: 1. There were reasonable efforts made to the next of kin of the patient or other to inform person in his immediate environment. 2. The cause of the coma is known and sufficient to establish the irreversible loss of all brain functions. 3. CNS depressant drugs, hypothermia (<35 ° C) and hypotension (MAP <55 mmHg) were excluded. Neuromuscular blockers do not contribute to the neurological findings. 4. All movements observed can be attributed fully the function of the spinal cord. 5. The cough reflex and / or pharygeale reflexes were tested and proven as missing. 6. corneal and pupillary reaction to light missing. 7. It carried no caloric responses to an ice water flushing at the eardrum. 8. An apnea test for at least 8 min shows no respiratory movements with a documented increase in PaCO2> 20 mmHg gene to the base value before the test. METHOD: The apnea test is performed by disconnecting the ventilator from the endotracheal tube. O2 (6 l / min) can be fed via diffusion from a cannula through the endotracheal tube. Despite the respiratory stimulus by the passive rising PaCO2 no spontaneous breathing for a period of 8-12 min is seen. Cave: The apnea test should be performed with extreme caution to minimize risk of hypoxia and hypotension, v. a. among potential organ donors. If the arterial blood pressure drops significantly during the test, the test should be stopped and an arterial blood sample drawn to determine whether the PaCO2 increased to> 55 mmHg either or increased by> 20 mmHg. These observations confirm the clinical diagnosis of brain death. 9. At least one of the following four criteria has been set properly: a. Points 2-8 were confirmed by two tests at intervals of at least 6 h. b. The points 2-8 were confirmed AND A EEG indicates electrocortical silence. A second investigation at least 2 hours after confirmation of the items 2-8 through the first. c. The points 2-8 were confirmed AND Conventional angiography, transcranial Doppler sonography or a brain scan with 99m Tc-HMPAO (technetium-99m Hexamethylpropylenaminoxim) shows no intracranial blood flow. A second investigation at least 2 hours after confirmation of the items 2-8 through the first. d. If one of the points 2-8 can not be determined because the injury or the state makes an evaluation impossible (. Eg include extensive facial injuries a caloric test out), apply the following criteria: Number of points that can be judged to be confirmed. Conventional angiography, transcranial Doppler sonography or a brain scan with 99m Tc-HMPAO (99m Technetium-Hexamethylpropylenaminoxim) shows no intracranial blood flow. A second investigation 6 h after the first confirms all evaluable points. MAP = mean arterial pressure. Adapted from American Academy of Neurology guidelines (1995). Prognosis The diagnosis of brain death is equivalent to the death of man. No one who meets the brain death criteria recovers. After brain death is confirmed, all supportive measures for heart and respiration are terminated. The termination of the respiration leads to terminal arrhythmias. During the terminal apnea spinal motor reflexes may occur; these show then mostly in the over-extension of the back, (so-called. Lazarus sign) in the neck rotation, stiffening the legs and bending of the upper extremities. Family members who want to be present when the ventilator is stopped, should be warned of the occurrence of these reflex movements.

Health Life Media Team

Leave a Reply