According to foreign media reports, what is brain death? Although the term is often used to remove ventilators and guide organ donation, there is no unified process for determining the occurrence of brain death.
brain death is a very old concept, its history can be traced back to the emergence of mechanical respiration and other technologies used to maintain oxygen levels in the human body after irreversible loss of brain function. The first clinical definition of brain death was published in 1968. The basic principle of this clinical definition is still applicable today: brain death is diagnosed when a patient loses consciousness, has no brainstem reflex (e.g. pupil response to light) and cannot breathe autonomously.
However, in some special cases, family members of patients refuse to accept the diagnosis of brain death. In these cases, the patient’s body can survive for a long time if the ventilator is used and nutrition is provided through the feeding tube. For example, in 2013, a 13-year-old Californian girl named hash mcmax was declared brain dead after routine surgery. His family refused to accept the diagnosis and took legal action to maintain the child’s life; eventually, the hospital allowed him to be discharged, and the child’s mother took him to New Jersey, where he was kept alive with a ventilator and a feeding tube. Disputes have followed. In the following years, some doctors claimed that the girl had signs of brain function recovery, such as brain electrical activity, but others believed that the girl’s brain function did not recover. In 2018, mcmace suffered from kidney and liver failure, and eventually she was removed from life support.
the divergent views in the McMaster case highlight some of the differences between medical and legal determination of brain death. Mcmace’s mother brought the girl to New Jersey because although the girl had died legally in California, New Jersey had a more tolerant religious exemption from the concept of death by neurological standards. In New Jersey, mcmace is not dead and can continue to receive coverage.
Dr. gene song Yung, a clinical neurologist at the University of Southern California’s Keck School of medicine, said the criteria for determining brain death vary from state to state. A study published in the journal Neurology in 2008 found that different health centers have different ways to determine brain death, ranging from the way clinical tests determine brain death to the removal of mechanical breathing to see if patients can breathe autonomously, and so on.
“this is a problem because in this place, by certain criteria, someone may be declared dead, but not elsewhere, and it can lead to confusion among the general public and even doctors about how to determine brain death,” Dr. Yung said.
Dr Yung is promoting an international effort, the world brain death project, to clarify what brain death is and to determine the basic requirements for brain death. A new proposal, published in the Journal of the American Medical Association on August 3, defines brain death – also known as “death by neurological standards” – as “complete and permanent loss of brain function caused by unresponsive coma with loss of consciousness, brain stem response, and loss of spontaneous breathing capacity.”. (critics of the concept of brain death sometimes cite brain function possibilities not covered by the definition, such as secreting hormones to maintain blood volume. In some cases, these functions still exist after the impairment of consciousness and brain stem function.)
although many professional associations and individual health systems have published their own guidelines and procedures, this effort is the first international collaboration among associations.
the recommendation outlines the details of how to determine whether a person meets the brain death criteria, such as excluding situations that may be similar to brain death criteria. For example, a patient taking a drug that causes paralysis may have limbs that do not respond to pain or have other similar reflexes. Other steps include making sure enough time has passed for a diagnosis, such as at least 24 hours for a brain death from hypoxia, and testing a series of basic reflexes controlled by the brainstem. The final test is the apnea test, which will determine whether someone can breathe autonomously, a process controlled by the brain stem. The guidelines also provide the first formal recommendation on how to determine whether brain death occurs in patients using extracorporeal membrane oxygenation (ECMO) to sustain life. Extracorporeal membrane oxygenation (ECMO) is a process that circulates blood in the human body so that it can be oxygenated by machine instead of cardiopulmonary bypass. Patients using ECMO do not need to use a ventilator, so the routine process of stopping the ventilator to check whether the patient can breathe autonomously is not feasible here. Instead, the new recommendations call for changes in machine settings so that machines no longer actively remove carbon dioxide from the blood. For living people, elevated levels of carbon dioxide in the blood trigger inspiratory activity. If carbon dioxide levels do not cause the patient to breathe, he or she is dead.
the new guidelines also discuss how healthcare professionals deal with patients whose families disagree to perform brain death assessment or refuse to accept brain death assessment results. Practitioners should be trained to understand the cultural background of the groups the hospital serves, and work with interdisciplinary teams (including religious advisers and palliative care specialists) in the treatment of patients with possible brain death. The advice also states that in some cases, such as when family members are coming to see the patient from other places, it is reasonable to continue using the ventilator for a period of time even after death has been declared. But it may not end the debate about the basic nature of brain death. At the level of the hospital, it is more willing to deal with the disputes on the basis of the facts rather than on the basis of the legal suggestions. The authors of the world brain death project concluded that the question of why immediate family members would require patients who have declared brain death to continue to use ventilators remains to be studied.
researchers from the world brain death project have found that despite the increasing number of new technologies, such as functional magnetic resonance imaging (fMRI), the diagnosis of brain death is still best performed by clinical bedside examination. Claude Hampshire, director of Neurology at Zuckerberg San Francisco hospital, said this is because the definition of brain death focuses on the function of the patient. Hampshire was not involved in the drafting of the new proposal.
“this basis is human beings, not some physiological functions or anatomical” is there blood flow? ” Or “are there any intact neurons in a certain location?” Hampshire said.
Hampshire also said that the procedures used by San Francisco hospitals to declare deaths on neurological standards have highly matched the new recommendations, but hospitals may also integrate some of the new guidelines, such as recommendations for ECMO patients.
Jose Suarez, director of the neuroscience intensive care unit at Johns Hopkins University, said the guidelines will be very important in standardizing brain death diagnosis in the United States, and will certainly be of great help internationally. Many of the less developed countries do not have a standard for the diagnosis of brain death, and the new recommendations may help them develop their own unified framework.