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.
Recognition of that state required the withdrawal of further artificial support so that death is allowed to occur, thus "sparing relatives from the further emotional trauma of sterile hope".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. In 1995, after a review by a Working Group of the Royal College of Physicians of London, the Conference of Medical Royal Colleges formally adopted the "more correct" term for the syndrome, "brainstem death" – championed by Pallis in a set of 1982 articles in the British Medical Journal – and advanced a new definition of human death as the basis for equating this syndrome with the death of the person. The suggested new definition of death was the "irreversible loss of the capacity for consciousness, combined with irreversible loss of the capacity to breathe". It was stated that the irreversible cessation of brainstem function will produce this state and "therefore brainstem death is equivalent to the death of the individual". Diagnosis
In the UK, the formal rules for the diagnosis of brainstem death have undergone only minor modifications since they were first published in 1976.