What is the basis for brain death diagnostics in Switzerland?

According to Article 9 of the Transplantation Law, a person is dead when the function of the brain, including the brain stem, has irreversibly failed. In principle, brain death can only be diagnosed if there is acute brain damage. Other disorders must be excluded with certainty as the cause or significant partial cause of the clinical findings. Brain death diagnosis is usually made purely clinically by examination by two physicians using the four-eyes principle, whereby one of the physicians must not be directly involved in the care of the patient and both must have qualifications and experience in brain death diagnosis. For the brain death diagnostic procedure, it is important whether there is primary or secondary brain damage due to a sustained circulatory arrest.

On July 1, 2007, the Transplantation Act came into force, giving Switzerland its first comprehensive federal regulation in the field of transplantation medicine. This law specifies the conditions under which organs, tissues or cells may be used for transplantation purposes. A prerequisite for the removal of organs, tissues or cells from a deceased person is the determination of death, for which medical ethical guidelines were formulated by the Swiss Academy of Medical Sciences (SAMS) and approved by the SAMS Senate in 2011. These guidelines can be found at www.samw.ch/de/Ethik/Richtlinien. According to the so-called extended consent regulation, organs may be removed after the determination of death if the consent of the donor or a third party authorized to represent the donor has been obtained.

The aim of this overview is to present the principles applicable in Switzerland for the diagnosis of brain death.

General principles of brain death diagnostics

According to Article 9 of the Transplantation Law, a human being is dead when the function of the brain including the brain stem has irreversibly failed, even if at that time the other organs and tissues still show the signs of being alive and are accordingly eligible for transplantation. This death criterion applies only when the question of transplantation or prognosis assessment arises. The definition of brain death is connected with the assumption that after the failure of the brain as a central control organ, the death of organs, tissues and cells is initiated.

Brain death as irreversible failure of all brain functions (there is no “brain stem death” as in Great Britain) is the result of modern intensive care medicine, because in case of complete failure of all brain functions also spontaneous respiration fails and under these conditions the cardiovascular function can only be maintained by controlled ventilation. In principle, brain death can only be diagnosed if there is acute brain damage. Other disorders (intoxications, hypothermia, circulatory shock, severe metabolic disorders, influence of sedating drugs, etc.) must be excluded with certainty as the cause or major partial cause of the clinical findings.

Primarily, brain death diagnosis is performed clinically

It must be emphasized that the diagnosis of brain death is usually made purely clinically by examination of two physicians according to the four-eyes principle, whereby one of the physicians must not be directly involved in the care of the patient and both must have qualifications and experience in brain death diagnosis such as a residency in neurology or intensive care medicine (for the determination of death in children: Specialist in neuropediatrics or pediatric intensive care). According to the present criteria, a repetition of the clinical examination after a certain time interval is only required for brain death diagnosis of infants beyond the neonatal period.

Only if neuroradiological imaging cannot explain the functional loss of the brain or examination of the cranial nerves is clinically impossible, proof of the irreversibility of the brain damage must be provided by an additional technical examination approved for this purpose, which in Switzerland must demonstrate the absence of cerebral perfusion. This can be done using transcranial Doppler or color duplex sonography, computed tomographic angiography (CTA), intra-arterial digital subtraction angiography, or magnetic resonance imaging with angiography (MRA). The additional examination must be performed by specialists who are in turn appropriately qualified for these examinations. In Switzerland, documentation of loss of brain electrical activity by EEG as evidence of irreversibility of brain injury is not used according to current guidelines.

Primary or secondary brain injury?

For the course of brain death diagnosis, it is important whether there is primary brain damage (e.g. intracranial hemorrhage, space-occupying medial infarction, space-occupying tumors, severe craniocerebral trauma, meningoencephalitides, etc.) or secondary brain damage due to a prolonged circulatory arrest, as a result of which there is an irreversible loss of brain function due to a lack of cerebral blood flow. In both situations, the cumulative determination of the clinical signs mentioned is required according to the dual control principle. In the case of brain death with sustained circulatory arrest documented by transthoracic echocardiography for more than 10 minutes, no further additional technical examination is required, since this excludes sufficient cerebral perfusion.

The distinction between supratentorial brain damage (cerebral damage) and infratentorial brain damage (cerebellar and/or brainstem damage) is not required in Switzerland. However, this is required in Germany, for example; an infratentorial brain injury necessarily entails an additional technical examination.

Concluding remarks

In principle, brain death is determined clinically on the basis of a comprehensive examination with evidence of the loss of brainstem reflexes and spontaneous breathing in comatose patients with acute brain damage according to the four-eyes principle. The diagnosis can be made unequivocally in the majority of patients in any intensive care unit without the need for further instrumental investigations.

The Swiss guidelines allow, on the basis of purely clinical parameters, to determine with certainty the complete and irreversible functional loss of the brain and the consequent infamous prognosis for the patient. The extent to which proof of brain death is a sure sign of death like cardiac and respiratory arrest, indicating the death of the entire human being, is ultimately a philosophical and spiritual question about the nature of death, which is also very much shaped by cultural traditions and cannot be answered in medical terms alone.

It is important to keep in mind that the moment of the determination of brain death is biographically of the greatest importance and significance, since through the connection to transplantation medicine the end of the life of one person can at the same time be the beginning of a new life of another person. Accordingly, dealing with brain-dead people poses a special challenge and responsibility for all involved (physicians, caregivers, relatives) in a variety of ways.