LETTER : Defining life and death

Sir: William Hartston ("Between the living and the dead", 12 March) discusses the concept of brain and brain stem death and states that some of the "recent remarkable cases of recovery [from coma] have followed readings that would have justified turning off all life support systems". This is not the case. Nobody, I emphasise, nobody has ever satisfied the guidelines laid down by the Royal Medical Colleges for the diagnosis of brain stem death and regained consciousness. The cases quoted in the media do not fulfil the criteria.

The guidelines state that to safely diagnose the irreversible loss of brain stem function the patient must satisfy various preconditions as well as have negative brain stem tests. The clinical tests for brain stem function are only valid if considered with various preconditions and exclusions; they are invalid if taken in isolation. The preconditions are as follows and it is their satisfaction which renders the diagnosis of brain stem death safe.

Context: Comatose patient is ventilator-dependent. Known cause for coma. Proof of irremediable structural brain damage.

Exclusions of potential causes of ventilator dependent coma: Hypothermia. Metabolic or endocrine disturbance. Drugs. Recent cardiac arrest.

If just one case arose wherein the guidelines were followed and a patient recovered, I (and assuredly the Royal Colleges) would no longer accept the brain stem formulation of death.

The brain stem death criteria were not introduced for the purposes of human organ donation. Whilst transplantation has benefited from the implementation of these criteria they were developed solely to avoid the extremely distressing scenarios where "corpses" were being ventilated in intensive care units.

Dr M M Jonas FRCA

Clinical Lecturer

Nuffield Department of

Anaesthetics

Oxford University