New developments in guidelines for brain death/death by neurological criteria

The declaration of brain death (BD), or death by neurological criteria (DNC), is medically and legally accepted throughout much of the world. However, inconsistencies in national and international policies have prompted efforts to harmonize practice and central concepts, both between and within countries. The World Brain Death Project was published in 2020, followed by notable revisions to the Canadian and US guidelines in 2023. The mission of these initiatives was to ensure accurate and conservative determination of BD/DNC, as false-positive determinations could have major negative implications for the medical field and the public's trust in our ability to accurately declare death. In this Review, we review the changes that were introduced in the 2023 US BD/DNC guidelines and consider how these guidelines compare with those formulated in Canada and elsewhere in the world. We address controversies in BD/DNC determination, including neuroendocrine function, consent and accommodation of objections, summarize the legal status of BD/DNC internationally and discuss areas for further BD/DNC research. This Review reviews changes introduced into the US brain death/death by neurological criteria (BD/DNC) guidelines in 2023 and compares these guidelines with those formulated elsewhere in the world. The authors highlight controversies and legal challenges in BD/DNC determination and discuss future research priorities. Brain death (BD), or death by neurological criteria (DNC), has been a medically and legally accepted formulation of death throughout the world for more than half a century.Guideline updates are intended to strengthen the methods and practice of BD/DNC determination; these include the World Brain Death Project (WBDP) in 2020, the Canadian guideline update in 2023, and the US combined paediatric and adult guidelines from multiple societies in 2023.New guidance has emerged for BD/DNC determination in several challenging circumstances, including hypothermia, carbon dioxide retention, primary infratentorial injury, extracorporeal membrane oxygenation and pregnancy.Guidelines continue to emphasize a meticulous and systematic approach, erring on the conservative side, to reduce the possibility of false-positive BD/DNC determination.Acceptable ancillary tests, which are only to be used when a complete clinical evaluation is not possible or safe, comprise tests of cerebral blood flow, such as four-vessel catheter angiography, radionuclide perfusion scintigraphy and transcranial Doppler ultrasonography (in adults only). EEG is no longer accepted as an ancillary test, and the most recent US guidelines and the WBDP do not permit the use of CT angiography.