Brain death criteria





With the advancement of positive-pressure ventilation in the 1950s, patients who sustained a catastrophic brain injury could be supported in hospitals after cessation of brain function. In 1968, an ad hoc committee at Harvard Medical School defined a new criterion for death, wherein the brainstem and higher cortical functions are absent despite preserved cardiac function.


Criteria for determining brain death


Since the release of the Harvard report, criteria for brain death continue to be refined. The American Academy of Neurology (AAN) released a clinician guideline for determining brain death in 2010 ( Table 5.1 ). However, each hospital has its own specific criteria. The information provided here is based on the AAN guideline.



TABLE 5.1

Checklist for Determination of Brain Death

From Wijdicks EFM, Valelas PN, Gronseth GS, Greer DM. Evidence-based guideline update: determining brain death in adults-report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2010;74:1911.








Prerequisites (all must be checked)

  • 1.

    Coma, irreversible and cause known


  • 2.

    Neuroimaging explains coma


  • 3.

    CNS depressant drug effect absent (if indicated toxicology screen; if barbiturates given, serum level <10 μg/mL)


  • 4.

    No evidence of residual paralytics (electrical stimulation if paralytics used)


  • 5.

    Absence of severe acid-base, electrolyte, or endocrine abnormality


  • 6.

    Normothermia or mild hypothermia (core temperature >36°C)


  • 7.

    Systolic blood pressure ≥100 mm Hg


  • 8.

    No spontaneous respiration


Examination (all must be checked)

  • 1.

    Pupils nonreactive to bright light


  • 2.

    Corneal reflex absent


  • 3.

    Oculocephalic reflex absent (tested only if C-spine integrity ensured)


  • 4.

    Oculovestibular reflex absent


  • 5.

    No facial movement to noxious stimuli at supraorbital nerve, temporomandibular joint


  • 6.

    Gag reflex absent


  • 7.

    Cough reflex absent to tracheal suctioning


  • 8.

    Absence of motor response to noxious stimuli in all four limbs (spinally mediated reflexes are permissible)

Apnea testing (all must be checked)

  • 1.

    Patient is hemodynamically stable


  • 2.

    Ventilator adjusted to provide normocarbia (partial pressure of carbon dioxide [Pa co 2 ] 35–45 mm Hg)


  • 3.

    Patient preoxygenated with 100% Fio 2 for >10 min to partial pressure of oxygen (Pao 2 ) >200 mm Hg


  • 4.

    Patient well oxygenated with a positive end-expiratory pressure (PEEP) of 5 cm of water


  • 5.

    Provide oxygen via a suction catheter to the level of the carina at 6 L/min or attach T-piece with continuous positive airway pressure (CPAP) at 10 cm H 2 O


  • 6.

    Disconnect ventilator


  • 7.

    Spontaneous respirations absent


  • 8.

    Arterial blood gas drawn at 8–10 min patient reconnected to ventilator


  • 9.

    Pa co 2 ≥60 mm Hg or 20 mm Hg rise from normal baseline value


OR:
Apnea test aborted
Ancillary testing (only one needs to be performed; to be ordered only if clinical examination cannot be fully performed because of patient factors, or if apnea testing inconclusive or aborted)

  • 1.

    Cerebral angiogram


  • 2.

    HMPAO SPECT


  • 3.

    EEG


  • 4.

    TCD

Time of death (date/month/year): _____________________________________________
Name of physician and signature: _________________________________________

CNS , Central nervous system; EEG , electroencephalogram; HMPAO , hexamethylpropyleneamine-oxime; SPECT , single photon emission computed tomography; TCD , transcranial Doppler ultrasonography.


Prerequisites


Two prerequisites must always be met before proceeding with clinical examination:



  • 1.

    An irreversible coma from a known cause—an untreatable catastrophic neurologic structural injury without known effective intervention


  • 2.

    Exclusion and treatment of all possible confounding factors, such as hypothermia; hypotension; drug intoxication; poisoning; effects of paralytic, sedative, analgesic, and/or neuromuscular blockers; major metabolic abnormalities (electrolytes, acid base, or endocrine) ; and other mimicking condition such as severe Guillain-Barré syndrome



Clinical examination


Once the prerequisites are met, complete a clinical examination in a stepwise fashion.



  • 1.

    Absent motor response to noxious stimuli in all limbs ( Fig. 5.1 A)



    • A.

      Spinal responses such as a brief, slow movement or flexion in upper limbs or flexion in the fingers that extinguish with repeated stimulation are consistent with brain death.



  • 2.

    Absent brainstem reflexes ( Fig. 5.1 B)



    • A.

      No corneal reflex: No blinking after water or swab touches cornea. Similar to spinal responses, facial myokymia from possible denervation of the facial nucleus is compatible.


    • B.

      Immobile eyes and no reaction to light: eyes can be skewed in position but should not deviate. Nystagmus or other spontaneous movement is not compatible with brain death.


    • C.

      Absent oculocephalic reflex: When the head is turned quickly, the eyes should remain fixed without any movement.


    • D.

      Absent oculovestibular reflex: No eye movement with ice water caloric testing. If the brainstem is intact, then the eyes slowly deviate toward the cold caloric stimulus.


    • E.

      Absent facial movement to noxious stimuli to supraorbital nerve or bilateral condyles of the temporomandibular joint. Jaw reflex is also absent.


    • F.

      Absent cough and gag reflexes



Tags:
Jan 1, 2021 | Posted by in NEUROLOGY | Comments Off on Brain death criteria

Full access? Get Clinical Tree
Get Clinical Tree app for offline access