brain death diagnosis_group 3

Determination of

Brain Death

Cleopatra Motsoari

Jenny Koo

ConceptsConcepts of Brain deathof Brain death

• Whole brain Irreversible cessation of all functions of the brain, including the brainstem.

• Neocortical Permanent cessation of the neocortex function. Clinical examination is used & the presence of brain stem activity is considered irrelevant.

• Brainstem Irreversible loss of the capacity of consciousness combined with the irreversible loss of breathing. No instrumental tests are required.

Elements necessary for BDDElements necessary for BDD

• It is important to know the Pathophysiology

• Clinical exam must be done by a well trained doctor– Pupil reflex– Corneal reflex – Painful stimulus over trigeminal – Oculo-vestibular reflex– Gag reflex– Cough reflex– Apneic test

• Complementary tests

Pre-requirementsPre-requirements

• Comatose Patient

• A Diagnosis of Neurological Injury

• Exclude Reversible Conditions– Drug,--Sedation or muscle relaxant– Hypothermia ( temp < 35oc), – Metabolic and electrolyte

disturbance – Arterial hypotension

• Exclude cervical spinal injury or other facial trauma that may invalidate the test result

• Ability to perform apnea testing

Pupil Reflex Corneal ReflexCorneal ReflexPupils show no response to bright light No response to a firm touch of the

cornea

Pain StimuliPain Stimuli

Look for Response in Cranial Nerve Distribution

Oculo-vestibular Oculo-vestibular

Not at Angle of Jaw

Slow injection of 20 ml ice-cold water into both external auditory meatus

Gag Reflex

• Stimulate the posterior pharyngeal wall with a tongue depressor bilaterally

• No gag response

• If patient is orally intubated, the gag reflex may be difficult to discern

Cough or tracheal Reflex

• Stimulate the tracheo-bronchial wall with a soft suction catheter

• No cough response

• Moving the endotracheal tube back and forth is NOT adequate

• The efferent for this reflex is via the phrenic nerve and can’t be assessed in patients with high cervical spinal cord injury

Apnea Test• ONLY proceed if all the above

reflexes are absent

• Pre-oxygenation– Oxygen cannula at 6L/min at

level of carina– T-Piece or CAPA circuit

connected to ET tube

• PaCO2: raised by 3-4 mmHg per minutes

• Watch out for cardiac dysrhythmias and systemic hypotension

Compatible with BDCompatible with BD

• Spinal reflex

• Sweating, blushing, tachycardia

• Normal Blood pressure without need for inotropic support

• Absence of diabetes insipidus (DI)

Incompatible with BDIncompatible with BD

• Decerebrate or decorticate posturing

• True extensor or flexor motor responses to painful stimuli

• Seizures

Spinal reflexSpinal reflex

Can be spontaneous or elicited by stimulation, including painful stimulus applied to limbs or sternum

• Extension-pronation of upper limbs or non-specific flexion of lower limbs’

• Undulating toe reflex• Lazarus sign• Deep tendon reflexes• Plantar responses, either flexor or extensor• Respiratory –like movement without significant tidal volume• Head turning

Discussion

Is my patient really dead?

What should I do if the clinical test can’t What should I do if the clinical test can’t complete?complete?

No brainstem reflexes no body movement

• Body movements generated by the spine can occur i.e. spinal reflexes

• Slow body movement, facial twitching, Babinski reflex, deep tendon, abdominal and cremasteric reflexes

• Sweating & blushing are not exclude BD

If patient is unstable during Apnea test?

• Systolic blood pressure < 90 mmHg

• Arterial oxygen desaturation

• Cardiac dysrhythmia

• STOP the test and reconnect the patient back to ventilator

• Confirmatory test may be required at discretion of physician

When to use confirmatory tests?• Cause of injury/death is unknown

• Presence of confounding factors e.g. drugs, hypothermia

• Complete clinical exam cannot be performed

• Conditions precluding apnea test e.g. cardiovascular instability, severe hypoxemic respiratory failure

• Serve to replace or expedite performance of a required repeat second clinical exam

• Transplant opportunities

Common Confirmatory Tests• Electrophysiological tests:

– EEG– Evoked potentials

• Cerebral blood flow evaluation tests:

– Conventional contrast angiography

– Transcranial Doppler ultrasonography

– Radionuclide brain scintigraphy Radionuclide angiography Brain SPECT scintigraphy

Who should perform the test?

• A skilled & knowledgeable doctor

• There must be no conflict of interest • The person authorizing removal of tissues and the person

removing tissues MUST NOT be responsible for determining brain death

Summary

• Six clinical test for brain-stem reflexes

• Confirmatory Tests

• It is the principle requisite for organ donation and

transplant

8-minutes video on Brain Death Diagnosis8-minutes video on Brain Death Diagnosis

“Establishing the diagnosis of brain death has never been easy for most physicians”

Dr. Mark S. George

Thank you