ABSTRACT
Death is defined as the irreversible loss of consciousness with the simultaneous loss of the ability to breathe. Tests to determine death vary between jurisdictions around the world. It can be determined either by neurological criteria or by circulatory criteria. The mode of determination also ultimately defines the organ donation process. Brain stem death occurs through the disruption of blood supply either due to 'coning' or a direct cerebrovascular accident. It can also be caused by global hypoxia, such as occurs in a cardiac arrest. 'Coning' is the process where the brain stem gets forced through the foramen magnum at the base of the skull due to increased intracranial pressure. This results in disruption of the blood supply to the brain stem and results in brain stem death. This disruption often manifests physiologically as marked hypertension and tachycardia followed by bradycardia and hypotension/cardiovascular collapse. Pupils will be fixed and dilated. There will be no spontaneous breaths or cough reflex.
