b r a i n s t e m d e a t h t e s t
DESCRIPTION
lecture by NasifTRANSCRIPT
- 1. BRAIN DEATH
PREPARED BY:NASIF YUSOPH
ICU STAFF NURSE
2. Thursday, July 21, 2011
Definition of Brain Death:
Brain death is the irreversible cessation of all functions of the
entire brain including the brain-stem.
. Permanent brain damage resulting in loss of brain function,
manifested by cessation of breathing and other vital reflexes,
unconsciousness with unresponsiveness to stimuli, absence of muscle
activity, and a flat electroencephalogram for a predetermined
length of time. Patients who are brain-dead may still exhibit
normal function of the heart, lungs, and other vital organs if they
are receiving artificial life support.
3. The diagnosis is made by clinical examination and objective
investigations.The diagnosis of brain death can be made in every
hospital with a well-functioning ICU and must be done as a part of
the general management of any patient fulfilling the criteria of
brain-death, irrespective of the issue of organ donation
4. Who is responsible for thediagnosis of brain death?
It is mandatory that a neurologist, a neuro-surgeon, an internist,
an ICU physician, an anesthesiologist, a pediatrician or a
consultant physician with experience in evaluation of brain-dead
patients performs the examinations.
Neither a nephrologist nor a transplant surgeon should be involved
in the establishment of diagnosis of brain death.
5. CAUSE OF BRAIN DEATH
BRAIN OEDEMA
Swelling can occur in specific locations or throughout the brain.
It depends on the cause. Wherever it occurs, brain swelling
increases the pressure inside your skull. That's known as
intracranial pressure, or ICP. This pressure can prevent blood from
flowing to your brain, which deprives your brain of the oxygen it
needs to function. Swelling can also block other fluids from
leaving your brain, making the swelling even worse. Damage or death
of brain cells may result.
6. Traumatic brain injury (TBI):
deceleration of the head can cause the injury. The most common
causes of TBI include falls, vehicle crashes, being hit with or
crashing into an object, and assaults. The initial injury can cause
brain tissue to swell. In addition, broken pieces of bone can
rupture blood vessels in any part of the head. The body's response
to the injury may also increase swelling. Too much swelling may
prevent fluids from leaving the brain.
7. Ischemic strokes
Ischemic stroke is the most common type of stroke and is caused by
a blood clot or blockage in or near the brain. The brain is unable
to receive the blood and oxygen it needs to function. As a result,
brain cells start to die. As the body responds, swelling
occurs.
8. Brain (intracerebral) haemorrhages
Haemorrhage refers to blood leaking from a blood vessel.
Hemorrhagic strokes are the most common type of brain haemorrhage.
They occur when blood vessels anywhere in the brain rupture. As
blood leaks and the body responds, pressure builds inside the
brain. High blood pressure is thought to be the most frequent cause
of this kind of stroke. Haemorrhages in the brain can also be due
to head injury, certain medications,
9. Brain abscesses
commonly occur when bacteria or fungi infect part of the brain.
Swelling and irritation (inflammation) develop in response to this
infection. Infected brain cells, white blood cells, live and dead
bacteria, and fungi collect in an area of the brain. Tissue forms
around this area and creates a mass.
While this immune response can protect the brain by isolating the
infection, it can also do more harm than good. The brain swells.
Because the skull cannot expand, the mass may put pressure on
delicate brain tissue. Infected material can block the blood
vessels of the brain
10. Thursday, July 21, 2011
Preconditions for the Diagnosis of Brain Death:
Patient is in coma and the cause of coma has been firmly
established.
Patient has no spont. respiration and is supported by a
ventilator.
The event causing brain-death occurred at least six hours
previously and the cause of death has been clearly determined
(i.e., head trauma, brain hemorrhage, etc).
Patient is not in cardiovascular shock.
Obvious metabolic and endocrinal derangements have been
corrected.
No response to any kind of stimuli.
Complete areflexia.However, simple spinal cord reflexes may be
present.
11. Thursday, July 21, 2011
Exclusions:
Patient should not be hypothermic.The core temperature must be
above 35.5 C before testing for brain death.
Patient is not receiving any sedatives, muscle relaxants,
anticonvulsants, hypnotics, narcotics or anti-depressants.Blood
levels of these drugs should be nil or insignificant if the patient
was on any of these drugs previously or an interval of five days
should lapse before testing for brain-death.
Patients with metabolic and endocrine causes of coma should be
excluded.
Patient should not have any signof cerebral activity like
decerebrate or decorticate posture and seizure activities.
12. Decerebrate Posture
13. Decorticate Posture
14. Brain stem reflexes test to be done for potentially brain death
patient
These test have to be done in the following order
If anyone of these reflexes is preserved there is no need to
proceed further.
Re-assessment to be done after 6 hours for adult,12 hours for
children and 24 hours for infant
Because as we grow older our brain tissue tolerance is
decreasing
15. Brainstem - The lower extension of the brain where it connects
to the spinal cord. Neurological functions located in the brainstem
include those necessary for survival (breathing, digestion, heart
rate, blood pressure) and for arousal (being awake and
alert).
Most of the cranial nerves come from the brainstem. The brainstem
is the pathway for all fiber tracts passing up and down from
peripheral nerves and spinal cord to the highest parts of the
brain.
16. Brain stem parts and its functions
Medulla Oblongata - The medulla oblongata functions primarily as a
relay station for the crossing of motor tracts between the spinal
cord and the brain. It also contains the respiratory, vasomotor and
cardiac centers, as well as many
mechanisms for controlling reflex activities such as coughing,
gagging, swallowing and vomiting.
Midbrain - The midbrain serves as the nerve pathway of the cerebral
hemispheres and contains auditory and visual reflex centers.
Pons - The pons is a bridge-like structure which links different
parts of the brain and serves as a relay station from the medulla
to the higher cortical structures of the brain. It contains the
respiratory center.
17. Brain stem
18. Thursday, July 21, 2011
Tests for Brain-stem reflexesa) Pupillary Response to light:Shine a
bright beam of light from a suitable source, e.g., a pen
flashlight, on to the open eyes.In a brain-dead patient, no
response, neither direct nor consensual, is seen to the stimulus in
either eye.Both eyes must be tested.Make sure that mydriatic or
meiotic eye drops or drugs have not been used in the recent past
prior to carrying out the test.
19. Thursday, July 21, 2011
Tests for Brain-stem reflexes
b) Corneal Reflex:Touch the cornea with a wisp of cotton wool.If
the brain stem is dead, no blinking response is noted on either
side.The test should be performed on both sides.
20. Thursday, July 21, 2011
Tests for Brain-stem reflexes
c) Oculo- Cephalic Reflex:
Normally when the head is rotated from side to side, the eyes move
in the opposite direction.
However, in brain death the eyes move with the head in the same
direction.
21. Thursday, July 21, 2011
Tests for Brain-stem reflexes
d) Vestibulo- Ocular Reflex (Caloric Test):
in normal caloric test, injection of 20 ml of iced cold water into
the external auditory meatus leads to nystagmus of the eye into the
other side. The test should be done on both sides.
In brain death, no nystagmus.
22. Thursday, July 21, 2011
Tests for Brain-stem reflexes
e) Upper and Lower Airways Stimulation (Gag and Cough
Reflexes):
Normally, stimulation of the pharynx, larynx and trachea by
catheter leads to gagging or coughing.
In brain death, no response.
23. Thursday, July 21, 2011
APNEA TEST
- The patient is preoxygenated with 100% O2 for 5 min before
disconnecting from ventilator.
- During the period of apnea 4-6 lr /min of O2 is supplied via ETT
suction catheter to avoid hypoxemia.
- The test is considered +ve if no respiratory attempts were found
while reaching a Pco2 of > 60 mmHg.
- The test should be aborted if there was any hypoxemia during the
test.
24. Thursday, July 21, 2011
Confirmatory Tests
ELECTROENCEPHALOGRAPHY (EEG)
- A minimum of eight scalp electrodes and ear lobe references
covering the major brain areas shall be used
- Should be tested for reactivity to loud noise
Recording will be done for at least 30 minutes
- Electromyographic artifacts can be seen sometimes in a patient
with isoelectric EEG, neuromuscular blocking agents like
pancuronium may be used, but during the recording only.
25. Thank
You