{"id":5132,"date":"2011-07-14T20:23:45","date_gmt":"2011-07-14T20:23:45","guid":{"rendered":"http:\/\/crashtext.org\/misc\/neurologic-criteria-for-death.htm\/"},"modified":"2016-01-15T15:01:29","modified_gmt":"2016-01-15T20:01:29","slug":"neurologic-criteria-for-death","status":"publish","type":"post","link":"https:\/\/crashingpatient.com\/intensive-care\/neurologic-criteria-for-death.htm\/","title":{"rendered":"Neurological Criteria for Death (Brain Death Protocols)"},"content":{"rendered":"

<\/span>Neurologic Criteria for Death (Brain Death Testing)<\/span><\/h2>\n

New guidelines form AAN (Neurology 2010;74:1911<\/a>)<\/p>\n

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<\/span>PRACTICAL (NON-EVIDENCE-BASED) GUIDANCE FOR DETERMINATION OF BRAIN DEATH<\/span><\/h2>\n

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Many of the details of the clinical neurologic examination to determine brain death cannot be established by evidence-based methods. The detailed brain death evaluation protocol that follows is intended as a useful tool for clinicians. It must be emphasized that this guidance is opinion-based. Alternative protocols may be equally informative.<\/p>\n

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The determination of brain death can be considered to consist of 4 steps.<\/p>\n

I. The clinical evaluation (prerequisites).<\/p>\n

A. Establish irreversible and proximate cause of coma.The cause of coma can usually be established by history, examination, neuroimaging, and laboratory tests.Exclude the presence of a CNS-depressant drug effect by history, drug screen, calculation of clearance using 5 times the drug’s half-life (assuming normal hepatic and renal function), or, if available, drug plasma levels below the therapeutic range. Prior use of hypothermia (e.g., after cardiopulmonary resuscitation for cardiac arrest) may delay drug metabolism. The legal alcohol limit for driving (blood alcohol content 0.08%) is a practical threshold below which an examination to determine brain death could reasonably proceed.There should be no recent administration or continued presence of neuromuscular blocking agents (this can be defined by the presence of a train of 4 twitches with maximal ulnar nerve stimulation).There should be no severe electrolyte, acid-base, or endocrine disturbance (defined by severe acidosis or laboratory values markedly deviated from the norm).<\/p>\n

B. Achieve normal core temperature.In most patients, a warming blanket is needed to raise the body temperature and maintain a normal or near-normal temperature (>36\u00b0C). After the initial equilibration of arterial CO2 with mixed central venous CO2, the Paco2 rises steeply, but then more slowly when the body metabolism raises Paco2.To avoid delaying an increase in Paco2, normal or near-normal core temperature is preferred during the apnea test.<\/p>\n

C. Achieve normal systolic blood pressure.Hypotension from loss of peripheral vascular tone or hypovolemia (diabetes insipidus) is common; vasopressors or vasopressin are often required. Neurologic examination is usually reliable with a systolic blood pressure >=100 mm Hg.<\/p>\n

D. Perform 1 neurologic examination (sufficient to pronounce brain death in most US states).If a certain period of time has passed since the onset of the brain insult to exclude the possibility of recovery (in practice, usually several hours), 1 neurologic examination should be sufficient to pronounce brain death. However, some US state statutes require 2 examinations.Legally, all physicians are allowed to determine brain death in most US states. Neurologists, neurosurgeons, and intensive care specialists may have specialized expertise. It seems reasonable to require that all physicians making a determination of brain death be intimately familiar with brain death criteria and have demonstrated competence in this complex examination. Brain death statutes in the United States differ by state and institution. Some US state or hospital guidelines require the examiner to have certain expertise.<\/p>\n

II. The clinical evaluation (neurologic assessment).<\/p>\n

A. Coma.<\/p>\n

* Patients must lack all evidence of responsiveness.Eye opening or eye movement to noxious stimuli is absent. Noxious stimuli should not produce a motor response other than spinally mediated reflexes. The clinical differentiation of spinal responses from retained motor responses associated with brain activity requires expertise.<\/p>\n

B. Absence of brainstem reflexes.<\/p>\n