Organ failure can occur within 1-2 weeks after brain death, and the early or late onset of organ failure is related to the disease causing brain death and the underlying disease of the patient. There are many causes of brain death, such as severe craniocerebral injury, hypertensive cerebral hemorrhage, and massive cerebral infarction can all cause brain death. In addition, patients after cardiopulmonary resuscitation can also experience brain death due to cerebral ischemia and hypoxia, although the heartbeat is restored. These patients can easily combine the failure of other organs due to some diseases, such as liver failure, kidney failure, coagulation system disorder, circulatory failure, respiratory failure, and will die within two weeks. With the improvement of modern blood purification technology and the application of advanced equipment such as extracorporeal artificial membrane lung, the time to maintain the patient after the appearance of brain death has increased greatly, but once brain death occurs, the prognosis is still very poor.