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.In the United Kingdom, death can be certified on the basis of a formal diagnosis of brainstem death, so long as this is done in accordance with a procedure established in "A Code of Practice for the Diagnosis and Confirmation of Death", published in 2008 by the Academy of Medical Royal Colleges. The premise of this is 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.This concept of brainstem death is also accepted as grounds for pronouncing death for legal purposes in India and Trinidad & Tobago. Elsewhere in the world, the concept upon which the certification of death on neurological grounds is based is that of permanent cessation of all function in all parts of the brain – whole brain death – with which the British concept should not be confused.
This test – the apnoea test – is dangerous, and may prove lethal.Two doctors, of specified status and experience, are required to act together to diagnose death on these criteria and the tests must be repeated after "a short period of time ... to allow return of the patients arterial blood gases and baseline parameters to the pre-test state". These criteria for the diagnosis of death are not applicable to infants below the age of two months. Prognosis and management
With due regard for the cause of the coma, and the rapidity of its onset, testing for the purpose of diagnosing death on brainstem death grounds may be delayed beyond the stage where brainstem reflexes may be absent only temporarily – because the cerebral blood flow is inadequate to support synaptic function, although there is still sufficient blood flow to keep brain cells alive and capable of recovery. There has recently been renewed interest in the possibility of neuronal protection during this phase by use of moderate hypothermia and by correction of the neuroendocrine abnormalities commonly seen in this early stage.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.