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無回答 2022/01/28 10:27:47
What conditions may lead to neurological death?
Acute brain injury: Head trauma from motor vehicle collisions, intracranial hemorrhage from any
cause including stroke, intracranial tumor or acute hydrocephalus.
Hypoxic-ischemic encephalopathy: Post-cardiac or respiratory arrest, near drowning, asphyxia,
hypovolemic shock.
Central nervous system (CNS) infection: Meningitis, encephalitis, generalized sepsis.
Miscellaneous: Metabolic encephalopathy from liver disease; diabetic ketoacidosis, metabolic disorders, acute hyponatremia or vasculitis.
What qualifications are needed to determine neurological death?
Physicians declaring neurological death should have full and current licensure for independent medical practice in Ontario (or relevant Canadian jurisdiction) and have skill and knowledge in the management of patients with severe brain injury and in the diagnosis of NDD. For donations to be eligible
for transplantation, two physicians must declare the patient’s death. The Trillium Gift of Life Network
Act states a physician whose judgment might be influenced owing to an association with a transplant
program or a proposed recipient cannot take any part in the declaration of death.
Whatis the legaltime of death?
The time of the first completed determination of neurological death is the legal time of death –
this is the time that is written on the death certificate.
What are the minimum clinical criteria needed for NDD?
The following minimum clinical criteria are required for NDD:
1. Proof of etiology that is capable of causing neurological death (in the absence of reversible conditions capable of imitating neu
2. Absence of reversible causes of coma, or confounding factors including:
a. Unresuscitated shock.
b. Low core body temperature < 34 degrees Celsius (or < 36 degrees Celcius for term newborns).
c. Treatable metabolic/endocrine/electrolyte disturbances (including hypernatremia,
hypoglycemia, severe hypophosphatemia, liver and/or renal dysfunction).
d. Peripheral nerve or muscle dysfunction due to disease or neuromuscular blocking agents
(pancuronium, succinylcholine, etc.).
e. CNS depressants/significant drug intoxications (e.g. alcohol, barbiturates, sedatives) – note that
therapeutic levels of anticonvulsants, sedatives and analgesics do not preclude the diagnosis.
3. Absence of brain stem reflexes/absence of bilateral movement, both spontaneous and in response
to stimulation (including seizures). Spinal cord reflexes are exempt. Deep pain testing must
include all extremities and above the clavicles.
4. Absence of respiratory effort, as established by apnea testing.
Assistance for the determination of neurological death is available by contacting the Trillium Gift of
Life Network’s Provincial Resource Centre at 1-877-363-8456 or 416-363-4438 (in the Toronto area).
What are the testing criteria to determine neurological death?
The following tests are done to determine neurological death:
1. CNS-mediated motor response to pain: Testing must include all extremities and above the
clavicles. Spinal cord reflexes are exempt.
2. Brain stem reflexes: All reflexes must be tested bilaterally (except cough and gag).
a.Pupillary response: In a darkened room, shine light into each eye and observe change in
pupil size. Absent reflex involves fixed dilated pupils that are unreactive to light. Intravenous
drugs, including conventional doses of atropine may influence pupil size, but the light response
remains the same. Topical ocular instillation of drugs, however, may produce non-reactive pupils.
b. Corneal reflex: Stimulate the cornea with a tissue and observe both eyelids for any response.
If no response such as blinking is observed, the reflex is absent.
c. Gag reflex: Stimulate the pharynx with a tongue blade /Yankauer. If it elicits no response, the
reflex is absent.
d. Cough reflex: If bronchial suctioning fails to initiate a cough, the reflex is absent.
e. Oculovestibular reflex (cold calorics): With head of bed elevated 30 degrees, syringe about
50 cc of ice-cold water into each ear canal ensuring patient’s eyes are open. Any movement
of one or both eyes excludes the diagnosis of neurological death. Prior to testing, a tympanic
membrane assessment is required as testing of this reflex is contraindicated if there is impaired
integrity of the tympanic membrane. Initial flushing of the ear canal may be needed if wax is
obstructing the membrane.
3. Apnea testing: Apnea testing involves driving up PaCO2 levels to a maximum point to elicit
the respiratory response (while supporting oxygenation). Cooler body temperature may impact
clinical testing for neurological death and can prolong the time required for apnea tests, due to
the decreased amount of CO2 produced by the body
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