Coma and Brain
Death
Objectives
O Define Coma and altered consciousness
O Understand the brain death exam
Altered Level of
Consciousness
O Coma: unconscious state
O Does not respond to stimuli appropriately
O Eyes closed, no purposeful motor response, no language
comprehension or expression
O Vegetative State: Must meet all 3 criteria
O No purposeful voluntary responses
O No evidence of language comprehension
O Sleep/wake cycles are apparent – eyes open, unable to interact
with environment
O Minimally conscious state: 1 or more
O Can follow simple commands
O Yes/no gestures even if not accurate
O Verbalizes
O Appropriate response to external stimuli: tracking, smiling,
reaching for things
When can you determine brain
death?
O Irreversible cause of coma
O Rule out other reasons for
unresponsiveness
O Ensure patient is:
O Normothermic
O Normotensive (even if on pressors)
O Has normal electrolytes
O Not on any drugs that could cause coma
Who can perform a brain
death exam?
O Any 2 physicians, not from the same team
O Different laws for different states
O Texas requires 2 exams 6 hours apart
Texas Law: Definition of
Death
O “(a) A person is dead when, according to ordinary
standards of medical practice, there is irreversible
cessation of the person's spontaneous respiratory
and circulatory functions. (b) If artificial means of
support preclude a determination that a person's
spontaneous respiratory and circulatory functions
have ceased, the person is dead when, in the
announced opinion of a physician, according to
ordinary standards of medical practice, there is
irreversible cessation of all spontaneous brain
function. Death occurs when the relevant functions
cease. (c) Death must be pronounced before artificial
means of supporting a person's respiratory and
circulatory functions are terminated.”
Components of Brain Death
Exam
O Assessment of cranial nerve  brain stem
function
O Assessment of any level of responsiveness
O Response to noxious stimulation
O Apnea OR (if patient too unstable for apnea test)
confirmatory test
O Nuclear flow study
O TCD’s
O EEG
O Cerebral angiography
Steps of the brain death exam
O Pupils not reactive to light (CNII and III)
O Pupils usually between 4-9mm; pinpoint pupils
not associated with brain death
O No corneal reflex (CNV and VII)
O Oculocephalic and oculovestibular reflex absent
(CN III, VI, VIII)
O Oculocephalic = doll’s eyes. Cannot do if c-spine
not cleared
O Oculovestibular = no eye deviation. Use 50 ml
cold water/saline and watch on each side for 1
minute
Steps of brain death exam
O No facial movement to noxious stim (CN V,
VII)
O Noxious stim should be central pain (stim
above nipples, TMJ, supraorbital)
O No cough or gag (CN IX and X)
What can confound your
exam?
O Pupillary response can be altered by: eye
trauma, scopolamine, atropine
O Oculovestibular response can altered by:
TM disruption, disease of inner ear,
anticholinergic drugs
O Cases of viper envenomations causing brain
dead like state d/t coma and
ophthalmoplegia
Apnea Test
O Pre-oxygenate patient
O Get baseline ABG – try to normalize PCO2 as
O
O
O
O
O
much as possible prior to apnea test
Place cut nasal cannula down ETT during test
One person needs to time the test – not the
physicians performing test
Pressors can be titrated during test
Stop test if: SBP cannot be maintained >90 or
sats <90%
Goal: PCO2 >60mmHg or 20mmHg rise over
pretest PCO2
Neurologic Exam
O Apnea test:
O Prerequisites: normotensive, normothermia,
O
O
O
O
O
O
O
eucapnia, normoxia
Patient should be preoxygenated for at least 10
minutes
Check PCO2 prior to test
Remove patient from ventilator, supply O2 and watch
for breathing for 8-10 minutes
Stop test if sats <85% or SBP <90
Can use a t-piece with CPAP
PCO2 >60 or 20mmHg above starting point
Inconclusive tests can be repeated
Brain Death
O Ancillary Tests: EEG, angio, nuclear scan, TCD,
CTA, MRA
O Not necessary
O Used if apnea test unable to be done
O In lieu of repeat exam
O Documentation: time of death
O Time when POC2 reached target level
O Time when ancillary test results reported
O TOSA required to be contacted once brain death
confirmed
Can patients move when thy
are brain dead?
O One study showed up to 55% of patients
have movements when brain dead
O Movements such as:
O Spinal reflexes causing movement of limbs
other then posturing
O Sweating, flushing
O DTR’s
O Breathing-like movements