Brain death

The notion of brain death generally refers to the permanent, complete, and irreversible loss of brain function. It's defined differently in different countries according to their laws. The concept of brain death is most important in the consideration of organ donations, as the donor being brain dead is a prerequisite for many organ donations.

When a person is brain dead, there is no hope of them returning to life, but their organs may be kept alive by mechanical ventilation and life-support, allowing the best conditions for organ donation.

In Hungary

In Hungary, brain death is defined in the law as “the irreversible cessation of all functions of the entire brain, including the brain stem”. To determine brain death, the following steps must be performed:

There must be no exclusion criteria present, like:

• Poisoning, drug effects
• Coma due to shock, metabolic, endocrine conditions
• Hypothermia or hyperthermia
• CNS infection (meningitis, encephalitis)

If no exclusion criteria are present, we must confirm the total absence of brain function and that this absence is irreversible.

Confirmation of total absence of brain function:

• No motor activity at all, neither spontaneous nor upon stimulation
• Absent brainstem reflexes (pupillary reflexes, corneal reflexes, gag reflex, etc.)
• Apnoea test – measures brainstem activity
  • The patient is ventilated with 100% oxygen
  • Then disconnected from the ventilator
  • The patient is observed for spontaneous breathing
  • After 10 minutes, an ABG is performed and the PaCO2 is measured
  • If PaCO2 > 60 mmHg, there’s no activity of the brainstem respiratory centre
• (Spinal reflexes may still be present)

Confirmation of the irreversibility of absent brain function during the observation period:

• Repeat the above tests
• Imaging tests may be used to shorten the observation time (ultrasound, scintigraphy, angiography)

Brain death must be confirmed by 3 independent specialist doctors who go through all the steps and who agree unanimously.

The duration of the observation period depends on the injury. In case of primary brain injury, it is 12 hours, in case of secondary brain injury, it is 72 hours. For children < 3 years old, the period is longer.

After being confirmed brain dead, the organ coordination office must be called to inquire as to whether the patient is a donor or not. Contact relatives to give information. Their consent is needed in case of child donors.

The patient must be treated in the ICU while waiting for surgery, to maintain optimal perfusion of donor organs. There, the following are necessary:

• Fluid therapy
• Proper ventilation
• Replacement of pituitary hormones
• Temperature maintenance

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