question: when someone dies, is he or she dead when the brain stops functioning or the heart?
comment: This is kind of a philosophical as well as legal question. The heart used to be the definition—when the heart stopped, you were dead. Though technically there are exceptions to that—when a person is decapitated, their heart will continue to beat (in an increasingly erratic fashion) for up to an hour, according to some scientists who observed this during the French Reign of Terror when lots of people were very publicly getting their heads chopped off. But nobody would say that that person was still alive. When they started being able to prolong the life of people in a coma by keeping them in life support, and when they started using organs for transplant, it became more clear that a different definition was needed. A person who is brain dead but whose heart is still beating thanks to life support, has no meaningful life left. And in order to use the donated organs of dead people, you need to keep the heart beating until the organs are harvested, but at the same time, you can’t harvest organs from a person who is alive. So brain death became a better definition for the modern age when the person is gone but there is still some brief bodily functioning thanks to heart-lung machines and such. In Japan, though, they still go by heart death, meaning there are virtually no organ donations, except kidneys from family donors, because they can’t harvest the organs while the heart is still beating, even if it’s only beating due to a machine.
passages: Brain death determinations are made in cases where breathing is supported by machines. Brain death is determined by there being no signs of brain function during neurological examination of a person with a beating heart. Confirmatory tests document either no blood flow to the brain, or no brain electrical activity in absence of factors known to produce reversible loss of brain function. Unlike cardiopulmonary death which sometimes involves a decision not to resuscitate the heart, brain death is a determination that the brain biologically cannot be resuscitated.
   Physiological death is now seen as a process, more than an event: conditions once considered indicative of death are now reversible. Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs. In general, clinical death is neither necessary nor sufficient for a determination of legal death. A patient with working heart and lungs determined to be brain dead can be pronounced legally dead without clinical death occurring. As scientific knowledge and medicine advance, formulating a precise medical definition of death becomes more difficult.
  
  Section::::Diagnosis.
  
  Section::::Diagnosis.:Signs.
   Section::::Medical criteria.
  
  Natural movements also known as the Lazarus sign or Lazarus reflex can occur on a brain-dead person whose organs have been kept functioning by life support. The living cells that can cause these movements are not living cells from the brain or brain stem; these cells come from the spinal cord. Sometimes these body movements can cause false hope for family members.
   In light of this we can now raise the question of whether patients declared dead by cardiocirculatory criteria are really dead. It is generally agreed that death occurs when the patient is in an irreversible state. Whether patients declared dead by cardiocirculatory criteria are really dead thus depends on what is meant by "irreversible," and the term is open to a stronger and weaker interpretation.
   Patients supported by methods that certainly maintain enough blood circulation and oxygenation for sustaining life during stopped heartbeat and breathing, such as cardiopulmonary bypass, are not customarily considered clinically dead. All parts of the body except the heart and lungs continue to function normally. Clinical death occurs only if machines providing sole circulatory support are turned off, leaving the patient in a state of stopped blood circulation.
  
  Section::::Controlled clinical death.
   The category of "brain death" is seen as problematic by some scholars. For instance, Dr. Franklin Miller, senior faculty member at the Department of Bioethics, National Institutes of Health, notes: "By the late 1990s... the equation of brain death with death of the human being was increasingly challenged by scholars, based on evidence regarding the array of biological functioning displayed by patients correctly diagnosed as having this condition who were maintained on mechanical ventilation for substantial periods of time. These patients maintained the ability to sustain circulation and respiration, control temperature, excrete wastes, heal wounds, fight infections and, most dramatically, to gestate fetuses (in the case of pregnant "brain-dead" women)."
   Brainstem death
  
  Brainstem death is a clinical syndrome defined by the absence of reflexes with pathways through the brainstem—the "stalk" of the brain, which connects the spinal cord to the mid-brain, cerebellum and cerebral hemispheres—in a deeply comatose, ventilator-dependent patient.
  
  Identification of this state carries a very grave prognosis for survival; cessation of heartbeat often occurs within a few days although it may continue for weeks if intensive support is maintained.
   The ability to breathe spontaneously depends upon functioning elements in the medulla – the 'respiratory centre'. In the UK, establishing a neurological diagnosis of death involves challenging this centre with the strong stimulus offered by an unusually high concentration of carbon dioxide in the arterial blood, but it is not challenged by the more powerful drive stimulus provided by anoxia – although the effect of that ultimate stimulus is sometimes seen after final disconnection of the ventilator in the form of agonal gasps.
   Conversely, in the case of Marlise Muñoz, a hospital refused to remove a brain dead woman from life support machines for nearly two months, despite her husband's requests, because she was pregnant.
  
  Section::::Record.
   No testing of testable brain stem functions such as oesophageal and cardiovascular regulation is specified in the UK Code of Practice for the diagnosis of death on neurological grounds. There is published evidence strongly suggestive of the persistence of brainstem blood pressure control in organ donors.
   A brain-dead individual has no clinical evidence of brain function upon physical examination. This includes no response to pain and no cranial nerve reflexes. Reflexes include pupillary response (fixed pupils), oculocephalic reflex, corneal reflex, no response to the caloric reflex test, and no spontaneous respirations.
   In the United Kingdom, the formal diagnosis of brainstem death by the procedure laid down in the official Code of Practice permits the diagnosis and certification of death on the premise that a person is dead when consciousness and the ability to breathe are permanently lost, regardless of continuing life in the body and parts of the brain, and that death of the brainstem alone is sufficient to produce this state.
   Those people maintaining that only the neo-cortex of the brain is necessary for consciousness sometimes argue that only electrical activity should be considered when defining death. Eventually it is possible that the criterion for death will be the permanent and irreversible loss of cognitive function, as evidenced by the death of the cerebral cortex. All hope of recovering human thought and personality is then gone given current and foreseeable medical technology. At present, in most places the more conservative definition of death – irreversible cessation of electrical activity in the whole brain, as opposed to just in the neo-cortex – has been adopted (for example the Uniform Determination Of Death Act in the United States). In 2005, the Terri Schiavo case brought the question of brain death and artificial sustenance to the front of American politics.
   Even by whole-brain criteria, the determination of brain death can be complicated. EEGs can detect spurious electrical impulses, while certain drugs, hypoglycemia, hypoxia, or hypothermia can suppress or even stop brain activity on a temporary basis. Because of this, hospitals have protocols for determining brain death involving EEGs at widely separated intervals under defined conditions.
   Published studies of patients meeting the criteria for brainstem death or whole brain death – the American standard which includes brainstem death diagnosed by similar means – record that even if ventilation is continued after diagnosis, the heart stops beating within only a few hours or days. However, there have been some very long-term survivals and it is noteworthy that expert management can maintain the bodily functions of pregnant brain dead women for long enough to bring them to term.
  
  Section::::Criticism.
   When brain death is suspected, reversible differential diagnoses such as, electrolyte, neurological and drug-related cognitive suppression need to be excluded. Testing for reflexes can be of help in the decision, as can the absence of response and breathing. Clinical observations, including a total lack of responsiveness, a known diagnosis, and neural imaging evidence, may all play a role in the decision to pronounce brain death.
  
  Section::::Society and culture.
   Death is the cessation of all biological functions that sustain a living organism. Death was once defined as the cessation of heartbeat (cardiac arrest) and of breathing, but the development of CPR and prompt defibrillation have rendered that definition inadequate because breathing and heartbeat can sometimes be restarted. Events that were causally linked to death in the past no longer kill in all circumstances; without a functioning heart or lungs, life can sometimes be sustained with a combination of life support devices, organ transplants and artificial pacemakers.
   The observed phenomena of lifelike qualities after death is not a new concept. In René Descartes' "Discourse on the Method", he notes that decapitated animals move and display characteristics of a living body a few seconds after decapitation which was published in 1637. This continued into the French Revolution where it was observed that people who had been beheaded showed movements in facial muscles and hearts could continue to beat for almost an hour past the time of beheading. The guillotine in some cases did not completely sever head from body. In 1875 an examiner named Pierre Jean Cabanis was assigned the duty of making sure a body was truly dead. There were also stories involving beheadings where the victims would stand up and walk around before falling dead. The ambiguity around brain death and true death has followed it to present day. In an effort to clarify some of these gray areas, the Harvard Medical Committee developed criteria for identifying a body as dead in 1968. These criteria required patients to be completely unaware and unresponsive to external stimuli, have no spontaneous muscle movements, and exhibit no reflexive response even when manipulated. They also required that an electroencephalography (EEG) show no signs of activity. The purpose of this report was to encourage physicians to distinguish brain death and irreversible coma from a persistent vegetative state where the patient still has some awareness and cycles through sleep and wakefulness.
   In 1979, the Conference of Medical Royal Colleges promulgated its conclusion that identification of the state defined by those same criteria—then thought sufficient for a diagnosis of brain death—"means that the patient is dead". Death certification on those criteria has continued in the United Kingdom (where there is no statutory legal definition of death) since that time, particularly for organ transplantation purposes, although the conceptual basis for that use has changed.
   While "brain death" is viewed as problematic by some scholars, there are certainly proponents of it that believe this definition of death is the most reasonable for distinguishing life from death. The reasoning behind the support for this definition is that brain death has a set of criteria that is reliable and reproducible. Also, the brain is crucial in determining our identity or who we are as human beings. The distinction should be made that "brain death" cannot be equated with one who is in a vegetative state or coma, in that the former situation describes a state that is beyond recovery.
   In the United States, if the patient is at or near death, the hospital must notify a transplant organization of the person's details and maintain the patient while the patient is being evaluated for suitability as a donor. The patient is kept on ventilator support until the organs have been surgically removed. If the patient has indicated in an advance health care directive that they do not wish to receive mechanical ventilation or has specified a do not resuscitate order and the patient has also indicated that they wish to donate their organs, some vital organs such as the heart and lungs may not be able to be recovered.
   BULLET::::- Donation after brain death. A person is declared brain dead if there is complete loss of all brain function
  
  BULLET::::- Donation after cardiac death. A person is declared cardiac dead if there is complete loss of all cardiac function
  
  Both types of deceased donors have complete and irreversible damage and returning to life is impossible. Thorough testing is carried out prior to confirming a person brain dead or cardiac dead.
  
  One deceased donor is able to save up to ten lives by donating the following:
  
  BULLET::::- Organs; Kidneys, pancreas, liver, lungs, heart and intestines
   While the heart is asystolic, there is no blood flow to the brain unless CPR or internal cardiac massage (when the chest is opened and the heart is manually compressed) is performed, and even then it is a small amount. After many emergency treatments have been applied but the heart is still unresponsive, it is time to consider pronouncing the patient dead. Even in the rare case that a rhythm reappears, if asystole has persisted for fifteen minutes or more, the brain will have been deprived of oxygen long enough to cause brain death.
  
  Section::::See also.
  
  BULLET::::- Agonal heart rhythm
   Brain death can sometimes be difficult to differentiate from other medical states such as barbiturate overdose, alcohol intoxication, sedative overdose, hypothermia, hypoglycemia, coma, and chronic vegetative states. Some comatose patients can recover to pre-coma or near pre-coma level of functioning, and some patients with severe irreversible neurological dysfunction will nonetheless retain some lower brain functions, such as spontaneous respiration, despite the losses of both cortex and brain stem functionality. Such is the case with anencephaly.
   Brain death is defined as irreversible cessation of all functions of the entire brain, including the brain stem: coma (with a known cause), absence of brainstem reflexes, and apnea. When doctors take away ventilation systems and patients fail to breathe, move, or show any signs of arousal on their own they are considered brain dead. This test is called an apnea test. The ventilator is taken away and is reconnected only if the person decided to be an organ donor. This definition can create some cognitive dissonance because not responding to stimulation may show a problem with the central nervous system, yet when someone has a beating heart and lungs that will still function with the help of a ventilator it is difficult for some to accept as death. Brain death patients have characteristics of the living and the dead.
  