Chapter 60 Brain Death
3 What are the current guidelines for determination of brain death?
5 What prerequisites must be met before performing a brain death examination?
These are defined in Box 60-1.
Box 60-1 Prerequisites to be Met Before Performing a Brain Death Examination
Coma, irreversible and cause known. (Glasgow Coma Scale score must be 3)
CNS depressant drug effect absent (if indicated, perform toxicology screen; if barbiturates given, serum level should be <10 mcg/mL)
No evidence of residual paralytics (verify by electrical nerve stimulation if paralytics used)
Absence of severe acid–base, electrolyte, endocrine abnormality
Normothermia or mild hypothermia (core temperature >36° C)
Systolic blood pressure ≥100 mm Hg (pressor agents are okay to use)
6 What findings should be present on brain death examination?
These are defined in Box 60-2.
Box 60-2 Findings that Should be Present on Brain Death Examination
Pupils nonreactive to bright light, corneal reflex absent bilaterally
Oculocephalic reflex absent (test only if C-spine cleared)
Oculovestibular reflex absent (cold-water caloric testing)
No facial movement to noxious stimuli at supraorbital ridge or temporomandibular joints
Cough reflex absent to deep tracheal suctioning
Absence of motor response to noxious stimuli in all four limbs (spinally mediated reflexes are permissible; see question 6)
8 What are the common spinally generated movements?
Deep-tendon reflexes: For example, Achilles, patellar, and biceps are by definition monosynaptic spinally mediated reflexes and hence often preserved despite brain death.
Abdominal reflexes: Deviation of the umbilicus toward a light stroking of the skin. Often preserved in brain-dead patients, it may be absent in normal or obese patients.
Triple flexion response or limb posturing: Stereotyped, nonpurposeful flexion or extension and internal rotation in response to noxious stimulus. (A movement may be purposeful if the limb reliably moves away from, rather than toward, an applied noxious stimulus.)
Lazarus sign: Considered a variant of opisthotonus. It consists of extensor posturing of the trunk, which may look like chest expansion, simulating a breath. It may be accompanied by raising and crossing of the arms in front of the chest or neck. This sign most often occurs in the setting of apnea testing or disconnection from the ventilator. Hence it may be upsetting for family members or health care providers to witness this reflex.
10 How do you perform apnea testing?
Normal blood pressure (systolic blood pressure >100 mm Hg)
No prior evidence of CO2 retention (i.e., chronic obstructive pulmonary disease, severe obesity)
Box 60-3 Procedures for Apnea Testing
Preoxygenate for at least 10 minutes with 100% oxygen to a PaO2 >200 mm Hg.
Reduce ventilation frequency to 10 breaths per minute to eucapnia.
Reduce positive end-expiratory pressure (PEEP) to 5 cm H2O (oxygen desaturation with decreasing PEEP may suggest difficulty with apnea testing).
If pulse oximetry oxygen saturation remains >95%, obtain a baseline blood gas level (PaO2, PaCO2, pH, bicarbonate, base excess).
Disconnect the patient from the ventilator.
Preserve oxygenation (e.g., place an insufflation catheter through the endotracheal tube and close to the level of the carina and deliver 100% O2 at 6 L/min).
Look closely for respiratory movements for 8 to 10 minutes. Respiration is defined as abdominal or chest excursions and may include a brief gasp.
Abort if systolic blood pressure decreases to <90 mm Hg.
Abort if oxygen saturation measured by pulse oximetry is <85% for >30 seconds.
Retry procedure with T-piece, continuous positive airway pressure 10 cm H2O, and 100% O2 12 L/min.
If no respiratory drive is observed, repeat blood gas analysis (PaO2, PaCO2, pH, bicarbonate, base excess) after approximately 8 minutes. If there is any reason to abort the test because of instability of the patient’s condition, draw an arterial blood gas sample immediately before reconnecting the ventilator.
If respiratory movements are absent and arterial PaCO2 is ≥60 mm Hg (or 20 mm Hg increase in arterial PCO2 over a baseline normal arterial PCO2), the apnea test result is positive (i.e., supports the clinical diagnosis of brain death).
If the test is inconclusive but the patient is hemodynamically stable during the procedure, it may be repeated for a longer period of time (10-15 minutes) after the patient is again adequately preoxygenated.
13 What ancillary tests can help with diagnosing brain death?



Measures of brain electrical activity

16 How many examinations are required to pronounce a patient brain dead?
Key Points Brain Death
1. Brain death is the irreversible loss of both brain and brainstem function from a known cause.
2. Brain death is rarely determined before 6 to 24 hours from neurologic injury.
3. The brain death examination should be performed by an experienced and knowledgeable physician.
4. It is not uncommon for brain-dead patients to make spinally mediated reflexive movements that are not indicative of preserved brain function. Families should be educated about this.
5. Brain death is a clinical diagnosis.
6. Ancillary tests may be helpful in confirming brain death but are not necessary or sufficient to make the diagnosis.
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2 Greer D.M., Varelas P.N., Haque S., et al. Variability of brain death determination guidelines in leading US neurologic institutions. Neurology. 2008;70:284–289.
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7 Wijdicks E.F.M., Varelas P., Gronseth G., et al. Evidence based guideline update: determining brain death in adults. Neurology. 2010;74:1911–1918.