Brain deathR99

Aristotle's concept of death relates solely to the heart. Plato was the first to suggest that the brain was the seat of the immortal soul (Schäfer 2015).

The first descriptions of brain death were written by Mollaret and Goulon, who published extensive and detailed research on brain death in 1959. In Germany, the Scientific Advisory Board first described criteria for brain death in November 1979. The last revision dates from 2022 (Wolff 1982).

Brain death is defined as the irreversible cessation of all brain functions while cardiac activity and physical and respiratory functions are maintained, possibly by artificial means. At the same time, brain death is the only type of brain damage that is recognized as synonymous with death (Kasper 2015).

Since the Transplantation Act was passed in 1997, brain death has been of particular importance, as it is considered a necessary condition for organ removal (Stoecker 2020).

The guidelines for the "determination of brain death" were first documented in 1982 and last revised in 2022 (Richter-Kuhlmann 2017). They precisely define the procedures for determining brain death or irreversible loss of brain function (IHA) (Herold 2018).

In Germany, irreversible brain death (ICBF) is determined according to the guidelines of the German Medical Association, which are currently available in their fifth update from 2022 (Reinhardt 2022).

The diagnosis of brain death comprises 3 essential elements:

- 1. extensive cortical destruction, which manifests itself in a deep coma and lack of response to all forms of stimulation

- 2. global damage to the brain stem, manifested by the loss of oculo-vestibular and corneal reflexes

- 3. destruction of the medulla, which manifests itself in complete and irreversible apnea (Kasper 2015)

Irreversible brain death is only diagnosed by specialists with several years of experience in intensive care medicine. For each examination, two qualified physicians who are not part of the potential organ or tissue donation team must independently and unanimously determine brain death (Reinhardt 2022).

Evidence must be provided (with the exception of children < 2 years of age, for whom special criteria apply):

• A. Acute severe primary or secondary brain damageThe cause and severity of the brain damage leading to death must be proven beyond doubt:
  • In the case of primary brain damage, a distinction must be made between supratentorial and infratentorial damage
  • Combined primary supratentorial and infratentorial as well as primary and additional secondary brain damage must be accurately recorded
  • Reversible causes of brain dysfunction such as attenuating drugs, intoxication, reversible brain stem disorders, neuromuscular blockade, circulatory shock, coma in metabolic, inflammatory or endocrine disease and primary or secondary hypothermia must be excluded (Reinhardt 2022)

• B. Clinical symptoms of brain failure must be checked:
• Light rigidity of both pupils, which are moderately to maximally dilated
  • Unconsciousness
  • Absence of the corneal reflex on both sides
  • Absence of the oculocephalic or vestibulo-ocular reflex on both sides
  • Absence of pharyngeal and tracheal reflexes
  • Lack of reaction to pain stimuli in the area of the trigeminal nerve on both sides or of cerebral reactions to pain stimuli outside the trigeminal nerve on both sides
  • Failure of spontaneous breathing (Reinhardt 2022)

• C. Proof of irreversibility of the findings in the case of primary or secondary brain damage by:
  • Repeated examinations at fixed intervals
    • In the case of primary supratentorial brain damage after 12 h at the earliest
    • In the case of secondary brain damage after 72 h at the earliest
  • Alternatively by supplementary examinations such as:
    • EEG
    • Evoked potentials
    • Visualization of cerebral blood flow
    • In the case of primary infratentorial brain damage - in contrast to primary supratentorial brain damage and secondary brain damage, both of which can be confirmed by repeated examinations - brain death can only be confirmed by an EEG or cerebral circulatory arrest (Reinhardt 2022)

All examination results and evidence must be recorded by two doctors. The time of death is the time at which all examinations and diagnostics have been completed (Reinhardt 2022).

- EEG

A zero line is detectable in the EEG (Unterhofer 2024).

- Transcranial Doppler sonography

This is used to detect cerebral circulatory arrest (Unterhofer 2024).

- Computed tomography

CT shows diffuse cerebral edema, sulci and basal cisterns are no longer visible. The gray matter appears iso- to hypodense compared to the white matter (Unterhofer 2024).

- Angiography

This can be used to demonstrate the lack of brain perfusion (Unterhofer 2024).

- Nuclear medicine examinations

Technetium-99 m scintigraphy only shows an uptake of technetium-99 m in the scalp, but not in the brain (Unterhofer 2024).

Brain death can be simulated in certain diseases or conditions, such as:

- Intoxication (especially with barbiturates)

- hypothermia

- Status epilepticus

- Metabolic coma

- Muscle relaxation (Unterhofer 2024)

1. Herold G et al. (2022) Internal Medicine. Herold publishing house
2. Herold G et al. (2018) Internal medicine. Herold publishing house 649 - 650
3. Kasper D L, Fauci A S, Hauser S L, Longo D L, Jameson J L, Loscalzo J et al. (2015) Harrison's Principles of Internal Medicine. Mc Graw Hill Education 1776
4. Reinhardt K, Scriba P C, Brandt S A, Clusmann H (2022) Guideline according to § 16 para. 1 sentence 1 no. 1 TPG for the rules for the determination of death according to § 3 para. 1 sentence 1 no. 2 TPG and the procedural rules for the determination of definitive, irreversible loss of total function of the cerebrum, cerebellum and brainstem according to § 3 para. 2 no. 2 TPG, Fifth update. Deutsches Ärzteblatt 1 - 31, DOI: 10.3238/arztebl.2022.rl_hirnfunktionsausfall_02
5. Schäfer D (2015) Death and medicine: A brief history of an approach. Springer Spektrum Verlag Berlin / Heidelberg 11
6. Stoecker, R. (2020). Brain death - philosophically. In: Wittwer, H., Schäfer, D., Frewer, A. (eds) Handbuch Sterben und Tod. J.B. Metzler, Stuttgart 124 - 129 https://doi.org/10.1007/978-3-476-05762-4_13
7. Unterhofer M, Antwerpes F et al. (2024) Brain death DocCheck Flexikon. DOI: https://flexikon.doccheck.com/en/brain-death
8. Wolff (1982) Statement of the Scientific Advisory Board of the German Medical Association on the question of the criteria for brain death: Decisions on the determination of brain death. German Medical Journal Issue 14, Edition A / B, 45 - 55