Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Review Meta Analysis
Diagnostic accuracy of ancillary tests for death by neurologic criteria: a systematic review and meta-analysis.
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. ⋯ PROSPERO (CRD42013005907); registered 7 October 2013.
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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. ⋯ 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.
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The new 2023 Canadian Brain-Based Definition of Death Clinical Practice Guideline provides a new definition of death as well as clear procedures for the determination of death (i.e., when that definition is met). Since physicians must practice in accordance with existing laws, this legal analysis describes the existing legal definitions of death in Canada and considers whether the new Guideline is consistent with those definitions. It also considers how religious freedom and equality in the Canadian Charter of Rights and Freedoms might apply to the diagnosis of brain death. ⋯ There are some differences between the wording of the new Guideline and existing legal definitions. To reduce confusion, these should be addressed through revising the legal definitions. In addition, future challenges to brain death based on the Charter of Rights and Freedoms can be anticipated. Facilities should consider and adopt policies that identify what types of accommodation of religious objection and what limits to accommodation are reasonable and well-justified.
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To synthesize the available evidence comparing noninvasive methods of measuring the cessation of circulation in patients who are potential organ donors undergoing death determination by circulatory criteria (DCC) with the current accepted standard of invasive arterial blood pressure (IAP) monitoring. ⋯ PROSPERO (CRD42021258936); first submitted 16 June 2021.
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A series of landmark experiments conducted throughout the 20th century progressively localized the regions involved in consciousness to the reticular activating system (RAS) and its ascending projections. The first description of the RAS emerged in 1949 through seminal experiments performed by Moruzzi and Magoun in feline brainstems; additional experiments in the 1950s revealed connections between the RAS and the thalamus and neocortical structures. This knowledge has allowed for the explanation of disorders of consciousness with exquisite anatomic precision. ⋯ Canadian guidelines acknowledge that the distinction between whole brain and brainstem formulations is unclear with respect to clinical implications for patients with isolated infratentorial injuries. This has led to variability in Canadian clinicians' use of ancillary testing when the mechanism of BD/DNC is suspected to be an isolated infratentorial injury. The present narrative review highlights these concepts and explores implications for determination of BD/DNC in Canada, with specific emphasis on the RAS and its relevance to both formulations.