The Diagnosis of Brain Death

In this hot case, the examiners invite the candidate to confirm or dispute the diagnosis of brain death.

To remind you, brain death is...

  • Unresponsive coma
  • Absence of brain stem reflexes
  • Absence of respiratory centre functions
  • Clinical setting which suggests that these findings are IRREVERSIBLE.

The patient must also satisfy the pre-conditions for testing:

  • Normothermia (over 35 degrees)
  • Normotension ( MAP >60)
  • Not sedated
  • Not paralyzed
  • Not in a state of electrolyte derangement (eg. hypoglycaemia)
  • Possessing at least one intact eye and one ear (to examine brainstem reflexes)
  • Able to breathe (to test for apnoea; i.e. high C-spine injury may disqualify you)

The candidate must assure themselves of the above features, and then go on to examine the brain stem reflexes.

Previous hot cases with this sort of theme to them can be found below.

Examination of the Patient to Determine Brain Death

The standard introduction

  • The examiner will give you a history.

The prelude to the dance

  • Wash hands.
  • Gown and glove.
  • Ask, if relevant:
    • "Can I turn on all the lights?"
    • "Are there any movement restrictions? Can I sit them up, or roll them on their side?"
    • "Is there a language barrier?"
  • Introduce yourself: “Hi Mr or Mrs Bloggs, I’m Dr So-and-so. I’m going to examine you.” One may feel silly doing so, but it demonstrates to the examiners that you still have some sort of respect for the (possibly dead) patient.

The Monitors

  • Rhythm
  • Rate
  • Morphology: QRS width,
  • MAP and abnormal morphology of the arterial waveform
    • Remember, the patient must be normotensive.
  • CVP and abnormal morphology of the CVP waveform
  • Ancillary waveforms eg. the PA catheter waveform
  • Oxygen saturation measurement, and the quality of the waveform
  • End-tidal CO2 waveform and level
  • Temperature: one must be normothermic to qualify for brain death testing.

A pacing box?

  • Pacing mode
  • Set rate

Sensitivity and pacing threshold may not be relevant.

The Ventilator

One can ask the examiners the following questions:

  • How are we oxygenating this patient?
  • How are we ventilating this patient?

One should ask about the following parameters:

  • FIO2
  • PEEP
  • Peak pressure
  • Plateau pressure
  • Tidal volume and minute volume

One should ask to look at the pressure-volume loops.

The key feature here is triggering. One must ask the examiners whether the patient has been observed to trigger the ventilator, and what the trigger settings are.

Urine catheter

  • Unusual colour
  • Anuria
  • Polyuria (DI or cold diuresis)

Drains (surgical, intercostal, etc)

There may be surgical drains (what is in them? How much of it?). Asking how much has been coming out may not be relevant in a hot case which focuses on the diagnosis of brain death.

The pleural catheters are also interesting. One should make a mental note of whether the ICCs are on free drainage or on suction. The content of these drains could be informative, especially if one notices blood or chyle. A bronchopleural fistula attached to a wall suction drain may produce enough flow to trigger the ventilator, and produce the false impression of respiratory effort.


A CVVHDF or SLEDD process may be in progress. The savvy candidate may wish to ask the following questions:

  • Which modality is being used?
  • What is the dose of dialysis?
  • What is the rate of fluid removal?
  • How is the circuit anticoagulated?
  • How long has this filter lasted?

Active cooling

The patient you are examining may be actively cooled. Ask about the target temperature; again, normothermia is required to determine brain death.


This stage is critically important. The drug and fluid infusions which are currently in progress give a clue as to what problem is currently being addressed. One should not neglect the labelled bags; the choice of antibiotics gives one some idea of where the source of sepsis is thought to be.

Any sedation or neuromuscular blockade should be mentioned to the examiners as a disqualifying feature. Additionally, one may wish to ask them about the most recent doses of paralysing or sedating agents, keeping in mind the possibility that clearance mechanisms are not working at 100%.


One should observe the following features of an EVD:

  • Set height
  • Whether it is open or closed
  • The CSF colour - eg. is it full of blood?

Intracranial pressure should be asked about, if it is not immediately obvious.

The physical examination

Expose and observe

Ideally, one should get the patient sitting up to 30-45°. This may not be possible. However, one should still ask for it.

Ideally, the patient should be exposed from the waist up. The candidate can then stand back and look for anything externally obvious:

  • Skin colour, eg. jaundice or the discolouration of chronic renal failure - hepatic encephalopathy and uraemia are the sort of metabolic disturbances that may invalidate brain death testing.
  • The evidence of trauma, eg. a C-spine collar - a high spinal injury is a contraindication to apnea testing.
  • Evidence of any spontaneous movements, eg. myoclonus - any seizure activity invalidates brain death testing
  • The presence of one intact eye and one intact ear.


Performing the GCS: you must ascertain that there is "unresponsive coma".

  • "Mr Bloggs!" One pauses to observe for eye opening.
  • Grab hold of both of the patient's hands.
  • "Can you squeeze my hands?"
  • If hand squeezing and eye opening is not observed, one administers a painful nail bed stimulus to both hands, to observe the response to pain.
  • If there is no response to pain in the hands, one may apply a similar response to the feet.

Hands, nail signs, pulse and the arterial line.

One should spent a second assessing whether the hands are warm or cold.

One can over-focus on the nails, but this focused examination is aimed to confirm or dispute the diagnosis of brain death, and the nails play a rather peripheral role in that.

Still, one ought to try to compare the radial pulses.


Tone of the upper limbs

Move up from the hands. While you are still holding the hands, you can perform a sort of gross examination of tone by pronating and supinating the wrists, and by flexing and extending the elbows.

The brain-dead patient may have increased tone.

Cubital fossa

Examine the cubital fossa for

  • Peripheral lines
  • Evidence of multiple venepunctures
  • Lymph nodes
  • Brachial pulse
  • The presence of an obvious AV fistula

The Neck

  • Inspect any central lines
  • Look again at the CVP

The brainstem reflexes

This part of the examination focuses on clinical brain death testing.

It occurs in a sequence:

Light reflex

Ask the examiners to dim the room lights.

Open both eyes. Each eye is exposed to light. The opposite pupil should constrict consensually.

This tests CN II (afferent) and CN III (efferent).

Corneal reflex

The cornea (not the sclera) is touched lightly with a moistened corner of a piece of gauze.

A normal reflex is to blink.

This tests CN V (afferent) and CN VII (efferent)

Facial pain sensation

Typically, this is performed by putting some pressure on the superior orbital notch.The patient should either open their eyes or localise. This tests CN V.

This test is an extension of the testing for unresponsive coma; with painful stimulus in the cranial nerve distribution, confusing spinal reflexes will not occur.

Oculocephalic reflex

In the comatose patient, as the head is moved from left to right, the eyes should move in the opposite direction. A fixed unchanging gaze is a negative test; the reflex is not working.

This tests CNs III, IV, VI, and most importantly VIII.

Cold caloric reflex

Cold water is funneled into the patient's ear. A positive reflex consists of the eyes turning towards the chilled ear. This is a more potent stimulus for CN VIII than the oculocephalic reflex.

Gag reflex

The Yankeur sucker is used to probe the posterior pharynx, on both sides. A gag reaction should result from this.

This collectively tests CN X and IX.

Cough reflex

While on the subject of CN X, one may test the cough reflex by suctioning the trachea.

This tests CN X.

This is also a convenient time to ask about the volume and character of the secretions.

With the cranial nerve reflexes negative, one may move on to apnoea testing.

One should ask the examiners whether this is permitted.

More than likely, one will instead be asked to describe how one would go about it.


  • Preoxygenate with 100% FiO2 for 5 minutes, and then turn off the ventilator.
  • Continue supplying oxygen via T-piece or something similar. Watch for absent breaths.
  • After 10 minutes, take an ABG to demonstrate that the CO2 is rising.
  • If there is still no respiratory activity at a PaCO2 of about 60mmHg, the apnoea test is positive; i.e. the patient is braindead.

With this established, one may go on to perform a brief examination of the remaining organ systems, to satisfy one's curiosity regarding the viability of the rest of the organ systems.

Chest palpation, percussion and auscultation


One puts both their hands on the chest to assess the symmetry of chest expansion.


One might wish to percuss the chest. If this is done in a slick fashion, it can be forgiven.

Changes in percussion resonance may be worth commenting on.


One may begin by auscultating the apices anteriorly. Then, one should auscultate as posteriorly as possible. The money is in the bases.

Palpation and auscultation of the praecordium


The clever candidate will make a big show of palpating both the apex and the right sternal edge.


One should auscultate in the following sequence:

  • Apex
  • Left sternal edge, lower
  • Left sternal edge, upper
  • Right sternal edge, lower
  • Left sternal edge, upper
  • Both carotids

The various clicks and murmurs one encounters are discussed elsewhere.

Abdominal palpation, percussion and auscultation

For this, one should ask to lay the patient flat.

Abdominal observation

  • Take a moment to behold the abdomen. One may ask the examiners to look under any surgical dressings; one is likely to be denied this part of the examination (they will tell you the wound looks clean and dry).

Abdominal palpation

  • All quadrants should be palpated.
  • Then, feel for the liver edge; observe respiratory excursion
  • Then, feel for the spleen.
  • Then, try to ballot the kidneys.

Abdominal percussion

  • This can be used to trace the outlines of the liver and spleen.
  • If there is some suspicion of ascites, one may ask to roll the patient, so shifting dullness can be better appreciated. The examiners may not permit this test.

Abdominal auscultation

  • One should spend a good length of time on this, if one suspects bowel obstruction or ileus.

Examination of the pelvis and groins

The pelvic content would have been palpated during the abdominal examination.

The more important part of this examination is the groin.

At this stage, the patient should be re-draped - cover them from the waist up, and uncover their legs.

Observation and palpation of the pelvis:

  • There may be a rash of thrush, or a groin haematoma, or an external fixation device.
  • The posterior pelvis and sacrum should ideally be palpated for pitting oedema.

Examination of the lines

  • One should take notice of anything going into or coming out of the femoral vessels.
  • There may be a vascath, a PiCCO catheter or some sort of angiography sheath. These are important clues. Why did this patient get an angiogram? What is the PiCCO for?

Examination of the genitals and rectum

  • A complete examination would call for the palpation of the testes, and a comment on their size. However, this may not be practical.
  • One should take note of any sort of waste management devices, eg. rectal tube, SPC or IDC.
  • One should definitely ask about performing a PR.

Once one is finished with the pelvis, one should cover it again, so that only the legs are sticking out.

Examination of the lower limbs

One should ask to remove TEDs and compression stockings.

  • One should observe whether the lower limbs are mottled, and whether they are of the same size (assymetrical swelling leads one to suspect lymphoedema or DVT)
  • One should palpate the larger muscles.
  • Pitting oedema should be palpated.
  • One should look at the feet, specifically for changes suggestive of chronic diabetic foot disease, or chronically poor vascular supply
  • Assess the dorsalis pedis and posterior tibial pulse.

The measured observations

Ask to see the obs chart. If it is not allowed, ask for the following:

  • Trends of blood pressure and heart rate
  • Temperature
  • Drain output
  • Urine output

One may also wish do demonstrate an interest in the trends of any sort of advanced haemodynamic monitoring, eg. cardiac index as measured by PAC or PiCCO

The laboratory investigations

One needs to show an interest in the following labs:

  • ABG
  • Routine bloods
  • Urinalysis
  • Culture results
  • CK, troponin, LFTs, pancreatic enzymes, inflammatory markers.

Imaging and other investigations

One should always ask for the following:

  • ECG
  • CXR

You sometimes want to see the following:

  • CSF analysis
  • CT or MRI results

One is looking for confirmation of some sort of "irreversible" brain-injuring pathology.


Case presentation and discussion: the patient is braindead.

"Mr Bloggs is braindead."

"I have come to this conclusion on the basis of the following findings: [regurgitate the conditions here]"

"I would like to convey my diagnosis to the family and the primary team."

"I would also like to explore the wishes of the deceased and their family regarding organ donation"

Case presentation and discussion: the patient cannot be braindead

"Mr Bloggs is not braindead."

"I have come to this conclusion on the basis of the following findings: [list the unmet preconditions or failed tests]"

"I would like to perform the following investigations in order to explore the possility of locked-in syndrome: [list of investigations - typically MRI, EEG]"

"Furthermore, I would like to enlist the help of the neurology service in order to explore the possible diagnosis of akinetic mutism or persisting vegetative state."

Case presentation and discussion: the patient cannot be evaluated for brain death

"I am unable to determine whether Mr Bloggs is braindead."

"The following features render the conventional brain death testing invalid [list the unmet preconditions]"

"I would like to perform the following investigations in order to confirm the absence of intracranial blood flow: [list of investigations - typically Tc99-HMPAO scan, 4-vessel angio, transcranial doppler, EEG and so forth]"

Number of previous hot cases in this topic: 2

2014, Paper 1

Royal Brisbane and Women’s Hospital

  • 41-year-old male, day 3 ICU, attempted self-hanging, asystolic at the scene and resuscitated with return of spontaneous circulation after 3 doses of adrenaline. Clinical findings were GCS 3 with absent brain stem reflex responses. Candidates were directed to assess him for brain death.
2012, Paper 1

Royal Brisbane Hospital

  • 63-year-old man collapse at home with VF arrest. Candidates were asked to assess his neurological status and discuss his prognosis, determination of brain death and what to say to his family.