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==Other Diagnostic Studies== | |||
===Evoked-Response Testing=== | |||
If there is absence of [[bilateral]] [[somatosensory evoked potentials]], then it is unlikely that the patient will survive.<ref>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.</ref><ref>Kaplan PW: Electrophysiological prognostication and brain injury from cardiac arrest. Semin Neurol 2006;26:403-412.</ref><ref>Young GB, Doig G, Ragazzoni A: Anoxic-ischemic encephalopathy: Clinical and electrophysiological associations with outcome. Neurocrit Care 2005;2:159-164.</ref> 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.<ref>Young GB, Doig G, Ragazzoni A: Anoxic-ischemic encephalopathy: Clinical and electrophysiological associations with outcome. Neurocrit Care 2005;2:159-164.</ref> | |||
= | ===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 [[diagnosis|diagnosed]] when all four of the following criteria are met:<ref>Ad Hoc Committee of the Harvard Medical School: A defi nition of irreversible coma. Report of the Ad Hoc Committee of the Harvard Medical | |||
==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:<ref>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.</ref><ref>Walker A: An appraisal of the criteria of cerebral death. JAMA 1977;237:982-986.</ref><ref>Shemie SD, Pollack MM, Morioka M, Bonner S: Diagnosis of brain death in children. Lancet Neurol 2007;6:87-92.</ref> | School to examine the defi nition of brain death. JAMA 1968;205:337-340.</ref><ref>Walker A: An appraisal of the criteria of cerebral death. JAMA 1977;237:982-986.</ref><ref>Shemie SD, Pollack MM, Morioka M, Bonner S: Diagnosis of brain death in children. Lancet Neurol 2007;6:87-92.</ref> | ||
1. There is [[coma]] with a loss of [[cerebral]] reactivity. | |||
1. There is coma with a loss of cerebral reactivity. | 2. There is absence of spontaneous [[respiration]]. | ||
3. There is a loss of [[brainstem]] [[reflex]]es ([[pupillary reflex|pupillary]], [[corneal reflex|corneal]], oculovestibular, and [[oculocephalic reflex|oculocephalic]]). In some definitions this is qualified by a requirement that the loss of [[reflex]]es exceeds 24 hours in duration. | |||
2. There is absence of spontaneous respiration. | 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. | ||
3. There is a loss of [[brainstem | |||
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. | |||
==References== | ==References== | ||
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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] 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.
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.