Coma and brain death | Coma

Coma and brain death

Brain death is a fixed definition of death introduced in 1968. It refers to the irreversible loss of all brain functions due to extensive nerve cell death, whereby the cardiovascular function is still maintained by controlled mechanical ventilation. It is regarded as the surest sign of death, so that so-called brain death diagnostics can be used to make an unambiguous assessment of a person’s death.

Even in the context of organ donation and transplantation, the determination of brain death or brain death diagnostics is an essential prerequisite for further procedures and subsequent organ removal. Brain death is diagnosed by two physicians (neurologists) acting independently of each other, who are not themselves involved in any planned transplantation/organ removal. However, brain death can only be diagnosed under intensive care conditions by maintaining the blood circulation and oxygen uptake of the body organs through mechanical ventilation, hormone replacement and circulatory therapy.

Clinical indications of brain death are the absence of spontaneous breathing, the absence of brainstem reflexes (such as the cough reflex, pupil reflex (light-fast), eyelid closure reflex), loss of consciousness (coma) and light-fast pupils. Additional mechanical indications may be a zero line in the brain waveform (EEG) as well as no signs of blood flow in the brain ultrasound or brain vessel imaging (angiography). Coma is the most severe form of a disturbance of consciousness, in which the patient is no longer able to be awakened even by repeated onset of pain stimuli.

It is caused by a pronounced disturbance of the cerebrum, which can result from a variety of underlying diseases. A coma is often caused, for example, by a stroke, a disorder of sugar metabolism, oxygen deficiency, liver or kidney failure or poisoning.