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

This boy has a catastrophic and irreversible brain injury from the hypoxic ischaemic encephalopathy, and the team is right to consider the determination of brain death. The cause is known and irreversible, the imaging shows the marked cerebral oedema, and the intracranial pressure could not be controlled, so the prerequisite of a devastating structural cause is met. The confounders must now be formally excluded before any neurological testing, the examination and the apnoea test performed by two clinicians, and the determination made across the two evaluations separated by the observation period. [3]

Question 1 (10 marks)

Outline the prerequisite checks and the bedside brainstem reflex examination you would perform in this child before the apnoea test, justifying each step. [1]

A full-mark answer states the prerequisites in turn, then performs the brainstem reflex examination with the findings that confirm the determination. [1]

The prerequisites (5 marks). The cause is known and irreversible, namely the hypoxic ischaemic encephalopathy with the cerebral oedema and the refractory intracranial pressure, confirmed on the imaging and the course. The core temperature is 37.0 degrees Celsius, which is at least 36 degrees Celsius, so the hypothermia confounder is excluded. The systolic blood pressure is 98 mmHg on low-dose noradrenaline, which is normal for a 3-year-old, so the hypotension confounder is excluded. The sedation has been off for over 48 hours, which is well beyond five half-lives for the common agents, and a barbiturate level is checked and confirmed therapeutic-zero. A drug and a toxin screen are sent, the electrolytes, glucose, calcium and the blood gas are checked and corrected, and a train of four confirms the full neuromuscular recovery. [1]

The brainstem reflex examination (5 marks). The boy is in a deep coma with a Glasgow Coma Scale of 3, with no eye opening, no verbal response, and no motor response to any stimulus. The pupils are fixed and dilated at the midposition, often four to nine millimetres, with no reaction to a bright light. The corneal reflex is absent to a touch of the cornea. The oculocephalic reflex, the doll's eye manoeuvre, is absent and is omitted if the cervical spine is not cleared. The oculovestibular reflex is absent to the cold caloric stimulus. The gag and the cough reflexes are absent to the pharyngeal and the tracheal suction. Each finding is recorded with the time and the names of the two independent senior clinicians, neither of whom is part of the transplant team. [4]

Question 2 (10 marks)

Describe the apnoea test, the observation period and the second examination, and then the organ donation pathway you would follow after the declaration of death. [3]

A full-mark answer gives the apnoea test thresholds, the observation period for the age, and the donation pathway with the dead donor rule. [3]

The apnoea test (4 marks). The boy is preoxygenated with pure oxygen for at least ten minutes to denitrogenate the lungs, and the PaCO2 is normalised to the baseline. The ventilator is then disconnected, and the oxygen is delivered to the trachea while the PaCO2 is allowed to rise, and the chest and the abdomen are watched for any respiratory effort. 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 test is negative, and brain death is excluded, the moment any respiratory effort appears, and the ventilator is reconnected at once. The test is aborted and an ancillary test such as the cerebral angiography is used if the boy becomes haemodynamically unstable or the oxygen saturation falls. [1][3]

The observation period and the second examination (3 marks). The determination requires two clinical evaluations, each including the apnoea test, performed by two independent senior clinicians and separated by an observation period. For a 3-year-old, who is an infant or a child older than 30 days, the observation period is 24 hours, as set by the pediatric guideline of Nakagawa and colleagues, and the ANZICS framework retains the two-examination standard for the child. The second examination repeats the full brainstem reflex testing and the apnoea test, and when the two evaluations are concordant the death is declared and recorded with the time, the date, the findings and the names of the two clinicians. [2]

The organ donation pathway (3 marks). 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 donor resuscitation continues to protect the organs, with the vasomotor collapse managed with the fluids and vasopressors, the diabetes insipidus with the vasopressin, and the hypothalamic hypothermia with the rewarming. The treating intensive care team remains separate from the transplant team throughout, to protect the dead donor rule and the trust of the family, and the consent is sought and recorded according to the local registry and the law. When the family declines the donation, the ventilator is withdrawn with dignity and the care shifts to the bereavement support. [9]