Topic: Brain Death
Subject: Medicine
A 35 year old man has been on life support systems for the past 48 hours following blunt head trauma. Which of the following is the most important criterion to declare the patient brain dead and to permit removal of life support systems?

The definition of brain death is constantly being revised. However, if there is no electrical activity on EEG, and if there is total loss of all brain stem reflexes, then it is safe to label an already irreversibly comatose patient as brain dead. The most definitive measure of absent brain activity is an EEG. However, remember that before interpreting a flat-line EEG, one must ascertain that the patient is not hypothermic or suffering from barbiturate overdose, since these can give the appearance of no electrical activity on an EEG.