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

Nature Reviews Neurology volume 20, pages 151–161 (2024)Cite this article

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Abstract

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.

Key points

  • 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.

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Fig. 1: History of BD/DNC.
Fig. 2: Worldwide prevalence of brain death/death by neurological criteria protocols.
Fig. 3: Neuroimaging in BD/DNC from various aetiologies.
Fig. 4: Ancillary tests for brain death/death by neurological criteria.

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Acknowledgements

The authors are grateful to A. Sarwal and M. Abdalkader for their assistance with the ultrasound and neuroimaging images for the figures.

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Authors and Affiliations

  1. Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA

    David M. Greer

  2. Boston Medical Center, Department of Neurology, Boston, MA, USA

    David M. Greer

  3. NYU Langone Medical Center, Departments of Neurology and Neurosurgery, New York, NY, USA

    Ariane Lewis

  4. The Children’s Hospital of Philadelphia, Department of Anaesthesiology and Critical Care Medicine, Philadelphia, PA, USA

    Matthew P. Kirschen

  5. Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA

    Matthew P. Kirschen

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D.M.G. researched data for the article. All authors contributed substantially to discussion of the content, wrote the article and reviewed and/or edited the manuscript before submission.

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Correspondence to David M. Greer.

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Greer, D.M., Lewis, A. & Kirschen, M.P. New developments in guidelines for brain death/death by neurological criteria. Nat Rev Neurol 20, 151–161 (2024). https://doi.org/10.1038/s41582-024-00929-z

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