Overview
A person who is declared brain dead is legally and physiologically dead. The State of California
Health and Safety Code, Section 7184, reads:
An individual who has sustained either (1) irreversible cessation
of circulatory
and respiratory functions, or (2) irreversible
cessation
of all functions of the entire brain, including the brainstem, is dead.
A determination of brain death must be made in accordance with
accepted medical standards.
Determination & Documentation
The patient must undergo two brain death determinations, at least three hours
apart, and meet
all
criteria listed below. The two examinations must be performed by
different
licensed physicians; the first exam by any (including house staff), the second
exam only by an attending physician not part of the primary team (i.e. a
neurosurgeon, neurologist or internist if the patient is admitted to the
Trauma Surgery service).
If
the patient meets all criteria for brain death on both examinations,
this should be noted in the medical record at the time of the second
exam.
This time becomes the time of legal death declaration. Don't forget
to
call the
coroner's office
as soon as death is declared.
ACMC Brain Death Criteria
1. No spontaneous movements and no response to deep painful bilateral stimuli
2. Core temperature > 35 °C
3. Sedatives, paralytic agents, exogenously ingested substances (ETOH,
cocaine, heroin) withheld for a period
sufficient to exclude them as a cause coma.
4. A phenobarbital level < 15 documented by laboratory assay.
5. Apnea as determined by the apnea test (see below).
7. Absence of all brain stem reflexes.
Apnea Test
1. Ventilate the patient with FiO2 of 1.0 at a rate and tidal volume to
achieve eucapnea on arterial blood gas
determination (pCO2 = 35 - 45 torr).
2. Keeping the patient on FiO2 of 1.0, set the ventilator rate to zero. CPAP
may be used for this. Inactivate
back-up apnea rate (i.e. do not allow the ventilator to override apnea).
3. Observe patient's chest closely for 10 minutes for signs of spontaneous
breathing.
4. Obtain ABG at the end of the 10 minute period if no spontaneous breaths are
observed. If patient breathes
he/she has "passed" the apnea test and
cannot
be considered brain dead.
5. If the patient does
not
breathe,
and
the 10 minute ABG pCO2 exceed
55 torr,
the patient has "failed" the
apnea test. If the 10 minute ABG pCO2 does not reach 55 torr, repeat the
test but wait longer than ten
minutes (try 15 minutes) before obtaining the ABG.
6. In patients with underlying COPD and baseline CO2 retention, adjust the
baseline FiO2 so as to bring initial
PaO2 into the 60-80 torr range.
Terminate
the apnea test prior to 10 minutes if (a) the patient has
spontaneous
respiratory efforts or (b) the patient becomes profoundly
hypoxic (O2
saturation < 80% by pulse-oximetry) or (c) the patient becomes
hemodynamically unstable.
Brain Stem Reflexes
1.
Pupils
fixed, dilated and unresponsive to direct light in the absence of drug effects
or ocular trauma.
2.
Corneal
reflexes absent bilaterally. The patient should not blink when the corneas
are lightly brushed.
3.
Cough
and
gag
reflexes absent bilaterally. The patient should not react when the pharynx is
stimulated or
when the endotracheal tube is suctioned.
4.
Doll's eye
response absent. When the head is turned from side to side, the eyes remain
fixed in the orbits.
5. Cold water
caloric
response absent bilaterally. Ice water is gently instilled into each external
ear canal using
a 30 ml syringe. No nystagmus (fast component towards irrigated ear) is
noted. Observe each side for one
minute and allow five minutes between sides.
References
1. Wijdicks EF. The diagnosis of brain
death. NEJM 2001;344:1215-1221
2. Curry PD, Bion JF. The diagnosis and management
of brain death. Curr Anesth Crit Care
1994;5:36-40
3. Benzel EC, Gross CD, Hadden TA, et al. The apnea
test for the determination of brain death. J Neuro-
surgery 1989;71:191-194
4. Belsh JM, Blatt R, Schiffman PL: Apnea testing in
Brain Death. Arch Intern Med 1986;146:2385-2388
