Brain death, death by neurological criteria and organ donation: Viva

Branch 1: The definition and the prerequisites

The candidate should define brain death as the irreversible cessation of all function of the entire brain including the brainstem, and state that it is one of two legal definitions of human death alongside circulatory death, so a declaration of brain death is a declaration of death in full. A strong candidate distinguishes the whole-brain formulation used in the United States from the brainstem formulation used in the United Kingdom, and notes that the bedside determination is identical across the two. [4]

If the examiner presses on the prerequisites, the candidate should state that no testing begins until a known and irreversible catastrophic cause is established and every reversible confounder is corrected. The candidate should list the confounders in turn: the hypothermia, excluded by a core temperature of at least 36 degrees Celsius, the hypotension, excluded by a blood pressure normal for the age, the central nervous system depressant drugs and the barbiturates, cleared for at least five half-lives and confirmed at a therapeutic-zero level, the metabolic and endocrine and acid-base derangements, corrected to the normal range, and the neuromuscular blockade, excluded with a train of four. A single uncorrected confounder invalidates the examination. [1][3]

Branch 2: The bedside examination and the apnoea test

If asked to run the examination, the candidate should describe the deep coma with a Glasgow Coma Scale of 3, the pupils fixed and dilated at the midposition of four to nine millimetres, and the absent corneal, oculocephalic, oculovestibular, gag and cough reflexes. The candidate should note that the oculocephalic manoeuvre is omitted if the cervical spine is not cleared, and that the examination is performed and documented by two independent senior clinicians. [1][4]

For the apnoea test, the candidate should give the sequence and the thresholds. The child is preoxygenated with pure oxygen for at least ten minutes, the PaCO2 is normalised to the baseline, the ventilator is disconnected, and the oxygen is delivered to the trachea while the PaCO2 is allowed to rise. An arterial blood gas is taken at the end, and the test is positive when there is no respiratory effort and the PaCO2 reaches at least 60 mmHg or rises by at least 20 mmHg from the baseline. The candidate should add that any respiratory effort makes the test negative and excludes brain death, that the ventilator is reconnected at once, and that an ancillary test such as the cerebral angiography is used when the apnoea test cannot be completed safely. [1][3]

Branch 3: The observation period and the organ donation conversation

If the examiner moves to the observation period, the candidate should state that the determination requires two clinical evaluations, each including the apnoea test, performed by two independent senior clinicians and separated by an observation period. The candidate should give the observation period of 48 hours for the term neonate up to 30 days and 24 hours for the infant and child older than 30 days, from the pediatric guideline of Nakagawa and colleagues, and note that the ANZICS framework retains the two-examination standard for the child. The 2023 consensus allows a single evaluation in the adult in some jurisdictions, but the pediatric standard retains the two examinations. [2]

For the organ donation, the candidate should state that after the death is declared the donation after brain death pathway is offered to the family in partnership with the donation specialist, because the brain-dead ventilated child is the ideal donor for the heart, lungs, liver, kidneys and pancreas. The candidate should explain that the treating intensive care team remains separate from the transplant team to protect the dead donor rule, that the donor resuscitation continues to protect the organs, and that the consent is sought according to the local registry and the law. [9]

A strong candidate closes by addressing the family who is unsure, stating that the determination of brain death is the declaration of a death that has already occurred and not the withdrawal of treatment, that the family is given the time and the information to understand the finding, and that the donation is offered without pressure and the family is supported whatever they decide. The candidate should reaffirm that the determination and the donation are separable, and that the bereavement support continues throughout. [3][9]