Other pertinent diagnostic studies in anoxic brain injury, include evoked-response testing, and the steps in diagnosing brain death.

If there is absence of bilateral somatosensory evoked potentials, then it is unlikely that the patient will survive.^[1][2][3] In particular, if there is no N20 response, there is a very highly likelihood of a vegetative state or death, with only 1 patient of 21 surviving in one study compared with survival in 11 of 26 patients surviving if the N20 response was positive.^[4]

If there is no longer brain activity, and there is 0% chance of the recovery of the patient, a patient is declared “Brain Dead”. Brain death is diagnosed when all four of the following criteria are met^[5][6][7]:

1. There is coma with a loss of cerebral reactivity.
2. There is absence of spontaneous respiration.
3. There is a loss of brainstem reflexes (pupillary, corneal, oculovestibular, and oculocephalic). In some definitions this is qualified by a requirement that the loss of reflexes exceeds 24 hours in duration.
4. There is no activity on the electroencephalogram (“electrocerebral silence”, a “flat electroencephalogram“) for > than 12 hours. This last criteria requires that the patient is not hypothermic or on sedative drugs. In some definitions > 24 hours is required.

Cardiology