SAMW(SAMS) The Swiss Academy of Medical Sciences published guidelines on the Determination of Death, which you can download.
Referred to SAMW, General remarks:
From the medical point of view, the best definition of death is the complete irreversible cessation of all brain function, including brainstem function. The brain is the controlling organ of the entire organism, and the loss of its function inevitably results in the death of all of the body's organs, tissues and cells.
The removel of organs is only permitted if a determination of death has been made on the basis of the clinical examinations and ancillary tests.Physicians and other members of the transplantation team must not be involved in the determination of death, nor may they exert pressure or influence of any kind on their colleagues who are responsible for the care of the dying person.