Brain death has different definitions regarding the significance of whether all functions of the brain have ceased. This has ethical, religious, critical care, and organ donation implications. Anaesthesia journal discusses the concept.
The UK accept brain death as ”the irreversible loss of the capacity for consciousness, combined with irreversible loss of the capacity to breathe… and therefore irreversible cessation of the integrative function of the brainstem” .
Canadian practice uses similar criteria to the UK. The CMAJ Guidelines recommend that: “neurologically determined death be defined as the irreversible loss of the capacity for consciousness combined with the irreversible loss of all brainstem functions, including the capacity to breathe”
Similarly, the World Health Organization defines death as ”the permanent loss of capacity for consciousness and all brainstem functions, as a consequence of permanent cessation of circulation or catastrophic brain injury.”
However, the US uses the Uniform Determination of Death Act , calling for the irreversible cessation of all functions of the entire brain”, and that a determination of death “must be made in accordance with accepted medical standards.” These two requirements may clash!
That some electrical activity or functions of the brain could persist despite brain stem death has been the basis of legal challenges in the US. Adoption of the WHO definition would be optimal but that is unlikely to occur any time soon in the US.
The full text discusses legal cases in the UK, Canada, and the US.