The Royal Colleges in the United Kingdom formulated clinical criteria for the diagnosis of brain death in 1976.


Conditions under which the diagnosis of brain death should be considered:

(1) The patient is deeply comatose:

(a) There should be no suspicion that this state is due to depressant drugs (narcotics, hypnotics, tranquilizers).

(b) Primary hypothermia as a cause of coma should have been excluded.

(c) Metabolic and endocrine disturbances which can be responsible for or can contribute to coma should have been excluded.

(2) The patient is being maintained on a ventilator because spontaneous respiration had previously become inadequate or had ceased altogether.

(a) Relaxants (neuromuscular blocking agents) and other drugs should have been excluded as a cause of respiratory inadequacy or failure. The effect of neuromuscular blocking agents should be excluded by elicitation of spinal reflexes (flexion or stretch) or by demonstration of adequate neuromuscular conduction with a conventional nerve stimulator.

(3) There should be no doubt that the patient's condition is due to irremediable structural brain damage. The diagnosis of a disorder which can lead to brain death should have been fully established.


Diagnostic tests for the confirmation of brain death, showing that all brainstem reflexes are absent, as follows:

(1) The pupils are fixed in diameter and do not respond to sharp changes in the intensity of incident light.

(2) There is no corneal reflex.

(3) The vestibulo-ocular reflexes are absent.

(4) No motor responses within the cranial nerve distribution can be elicited by adequate stimulation of any somatic area.

(5) There is no gag reflex or reflex response to bronchial stimulation by a suction catheter passed down the trachea.

(6) No respiratory movements occur when the patient is disconnected from the mechanical ventilator for long enough to ensure that the arterial carbon dioxide tension rises above the threshold for stimulation of respiration.


The decision to withdraw life support after the above criteria are met should be made by at least two physicians experienced in the care of such cases.



• This is based on clinical evaluation of the patient and does not incorporate newer diagnostic technologies not available when the criteria were formulated.


To read more or access our algorithms and calculators, please log in or register.