Infratentorial Brain Injury Among Patients Suspected of Death by Neurologic Criteria: A Systematic Review and Meta-analysis

An Update on Brain Death/Death by Neurologic Criteria since the World Brain Death Project

The World Brain Death Project (WBDP) is a 2020 international consensus statement that provides historical background and recommendations on brain death/death by neurologic criteria (BD/DNC) determination. It addresses 13 topics including: (1) worldwide variance in BD/DNC, (2) the science of BD/DNC, (3) the concept of BD/DNC, (4) minimum clinical criteria for BD/DNC determination, (5) beyond minimum clinical BD/DNC determination, (6) pediatric and neonatal BD/DNC determination, (7) BD/DNC determination in patients on ECMO, (8) BD/DNC determination after treatment with targeted temperature management, (9) BD/DNC documentation, (10) qualification for and education on BD/DNC determination, (11) somatic support after BD/DNC for organ donation and other special circumstances, (12) religion and BD/DNC: managing requests to forego a BD/DNC evaluation or continue somatic support after BD/DNC, and (13) BD/DNC and the law. This review summarizes the WBDP content on each of these topics and highlights relevant work published from 2020 to 2023, including both the 192 citing publications and other publications on BD/DNC. Finally, it reviews questions for future research related to BD/DNC and emphasizes the need for national efforts to ensure the minimum standards for BD/DNC determination described in the WBDP are included in national BD/DNC guidelines and due consideration is given to the recommendations about social and legal aspects of BD/DNC determination.

The 2023 AAN/AAP/CNS/SCCM Pediatric and Adult Brain Death/Death by Neurologic Criteria Consensus Practice Guideline: A Comparison With the 2010 and 2011 Guidelines

In collaboration with the American Academy of Pediatrics, Child Neurology Society, and Society for Critical Care Medicine, the American Academy of Neurology formulated an updated, evidence-informed consensus-based guideline for pediatric and adult brain death/death by neurologic criteria (BD/DNC) determination. In comparison with the prior guidelines, the revisions and additions in this guideline, which are summarized in this review, are intended to (1) ensure recommendations are conservative, yet practical, and emphasize circumstances in which BD/DNC determination should be delayed or deferred, so as to minimize the risk of a false-positive BD/DNC determination; and (2) provide guidance about aspects of BD/DNC determination that clinicians find challenging and/or controversial. We hope that clinicians throughout the United States will use this information to revise their hospital BD/DNC determination policies to conform to the standardized process for BD/DNC determination described in the new guideline, to ensure that every BD/DNC evaluation is consistent and accurate.

Diagnostic accuracy of ancillary tests for death by neurologic criteria: a systematic review and meta-analysis

PURPOSE

Ancillary tests are frequently used in death determination by neurologic criteria (DNC), particularly when the clinical neurologic examination is unreliable. Nevertheless, their diagnostic accuracy has not been extensively studied. Our objective was to synthesize the sensitivity and specificity of commonly used ancillary tests for DNC.

SOURCE

We performed a systematic review and meta-analysis by searching MEDLINE, EMBASE, Cochrane databases, and CINAHL Ebsco from their inception to 4 February 2022. We selected cohort and case-control studies including patients with 1) clinically diagnosed death by neurologic criteria or 2) clinically suspected death by neurologic criteria who underwent ancillary testing for DNC. We excluded studies without a priori diagnostic criteria and studies conducted solely on pediatric patients. Accepted reference standards were clinical examination, four-vessel conventional angiography, and radionuclide imaging. Data were directly extracted from published reports. We assessed the methodological quality of studies with the QUADAS-2 tool and estimated ancillary test sensitivities and specificities using hierarchical Bayesian models with diffuse priors.

PRINCIPAL FINDINGS

Overall, 137 records met the selection criteria. One study (0.7%) had a low risk of bias in all QUADAS-2 domains. Among clinically diagnosed death by neurologic criteria patients (n = 8,891), ancillary tests had similar pooled sensitivities (range, 0.82-0.93). Sensitivity heterogeneity was greater within (σ = 0.10-0.15) than between (σ = 0.04) ancillary test types. Among clinically suspected death by neurologic criteria patients (n = 2,732), pooled ancillary test sensitivities ranged between 0.81 and 1.00 and specificities between 0.87 and 1.00. Most estimates had high statistical uncertainty.

CONCLUSION

Studies assessing ancillary test diagnostic accuracy have an unclear or high risk of bias. High-quality studies are required to thoroughly validate ancillary tests for DNC.

STUDY REGISTRATION

PROSPERO (CRD42013005907); registered 7 October 2013.

A brain-based definition of death and criteria for its determination after arrest of circulation or neurologic function in Canada: a 2023 clinical practice guideline

This 2023 Clinical Practice Guideline provides the biomedical definition of death based on permanent cessation of brain function that applies to all persons, as well as recommendations for death determination by circulatory criteria for potential organ donors and death determination by neurologic criteria for all mechanically ventilated patients regardless of organ donation potential. This Guideline is endorsed by the Canadian Critical Care Society, the Canadian Medical Association, the Canadian Association of Critical Care Nurses, Canadian Anesthesiologists' Society, the Canadian Neurological Sciences Federation (representing the Canadian Neurological Society, Canadian Neurosurgical Society, Canadian Society of Clinical Neurophysiologists, Canadian Association of Child Neurology, Canadian Society of Neuroradiology, and Canadian Stroke Consortium), Canadian Blood Services, the Canadian Donation and Transplantation Research Program, the Canadian Association of Emergency Physicians, the Nurse Practitioners Association of Canada, and the Canadian Cardiovascular Critical Care Society.

Infratentorial brain injury and death by neurologic criteria in Canada: a narrative review

There are two anatomic formulations of death by neurologic criteria accepted worldwide: whole-brain death and brainstem death. As part of the Canadian Death Definition and Determination Project, we convened an expert working group and performed a narrative review of the literature. Infratentorial brain injury (IBI) with an unconfounded clinical assessment consistent with death by neurologic criteria represents a nonrecoverable injury. The clinical determination of death cannot distinguish between IBI and whole-brain cessation of function. Current clinical, functional, and neuroimaging assessments cannot reliably confirm the complete and permanent destruction of the brainstem. No patient with isolated brainstem death has been reported to recover consciousness and all patients have died. Studies suggest a significant majority of isolated brainstem death will evolve into whole-brain death, influenced by time/duration of somatic support and impacted by ventricular drainage and/or posterior fossa decompressive craniectomy. Acknowledging variability in intensive care unit (ICU) physician opinion on this matter, a majority of Canadian ICU physicians would perform ancillary testing for death determination by neurologic criteria in the context of IBI. There is currently no reliable ancillary test to confirm complete destruction of the brainstem; ancillary testing currently includes evaluation of both infratentorial and supratentorial flow. Acknowledging international variability in this regard, the existing evidence reviewed does not provide sufficient confidence that the clinical exam in IBI represents a complete and permanent destruction of the reticular activating system and thus the capacity for consciousness. On this basis, IBI consistent with clinical signs of death by neurologic criteria without significant supratentorial involvement does not fulfill criteria for death in Canada and ancillary testing is required.