Anoxic brain injury other diagnostic studies
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Other pertinent diagnostic studies in anoxic brain injury, include evoked-response testing, and the steps in diagnosing brain death.
Other Diagnostic Studies
Evoked-Response Testing
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]
Diagnosis of Brain Death
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]:
- There is coma with a loss of cerebral reactivity.
- There is absence of spontaneous respiration.
- 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.
- 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.
References
- ↑ Chen R, Bolton CF, Young B: Prediction of outcome in patients with anoxic coma: A clinical and electrophysiological study. Crit Care Med 1996;24:672-678.
- ↑ Kaplan PW: Electrophysiological prognostication and brain injury from cardiac arrest. Semin Neurol 2006;26:403-412.
- ↑ Young GB, Doig G, Ragazzoni A: Anoxic-ischemic encephalopathy: Clinical and electrophysiological associations with outcome. Neurocrit Care 2005;2:159-164.
- ↑ Young GB, Doig G, Ragazzoni A: Anoxic-ischemic encephalopathy: Clinical and electrophysiological associations with outcome. Neurocrit Care 2005;2:159-164.
- ↑ Ad Hoc Committee of the Harvard Medical School: A defi nition of irreversible coma. Report of the Ad Hoc Committee of the Harvard Medical School to examine the defi nition of brain death. JAMA 1968;205:337-340.
- ↑ Walker A: An appraisal of the criteria of cerebral death. JAMA 1977;237:982-986.
- ↑ Shemie SD, Pollack MM, Morioka M, Bonner S: Diagnosis of brain death in children. Lancet Neurol 2007;6:87-92.