A Brain-Based Definition of Death and Criteria for its Determination After Arrest of Circulation or Neurologic Function in Canada: Frequently Asked Questions
History and Context
In Canada, definitions of death may be found in provincial/territorial statutes and vary from province to province. Where a definition is included within this legislation, death is either defined as cessation of brain function, or includes brain death. Otherwise, it is left to the common law definition adopted by judges, who have accepted cessation of brain or cardiorespiratory function. In the majority of provinces, criteria for death determination in the context of organ donation are delegated by statutes to accepted medical practice.
Previous Canadian death determination guidelines that form the basis of accepted medical practice describe death as arising after cessation of brain function, circulatory function, and both circulatory and brain function.
Medical, legal, and ethical issues have emerged, all of which collectively provided strong impetus for review and update of the guidelines, including:
- Development of international standards to harmonize international practices for death determination by neurologic criteria (DNC)
- Advances in knowledge and emerging evidence related to physiology of the dying process after withdrawal of life-sustaining measures (WLSM) for death determination by circulatory criteria (DCC), and the use of ancillary investigation for DNC
- Recent legal cases in Ontario where families challenged DNC and the accepted medical guidelines
- Advances in technological support of organ function to support life prior to death, or preserve organs after death.
Furthermore, there has been a 16-year gap for the adult/pediatric DNC and organ donation after DCC recommendations, and five-year gap in pediatric organ donation after DCC recommendations. In the interim, not only has the volume of evidence available to inform recommendations increased, but, since 2006, so has the required rigour for the process of guideline development.
In response, Health Canada’s Organ Donation and Transplantation Collaborative funded a project entitled, “A Brain-Based Definition of Death and Criteria for its Determination After Arrest of Circulation or Neurologic Function in Canada,” a partnership between Canadian Blood Services, the Canadian Critical Care Society, and the Canadian Medical Association.
The project’s objectives were to develop a unified brain-based definition of death and update the criteria for its determination after devastating brain injury or circulatory arrest.
The recommendations outlined in the clinical practice guideline will result in changes to Canadian practice in several key areas:
Definition of death
- A single definition of death based on the permanent cessation of brain function.
Death determination by circulatory criteria (DCC):
- Five recommendations related to:
- Monitoring devices
- Cessation of circulation
- Observation time
Death determination by neurologic criteria (DNC):
- Fifteen recommendations related to:
- Clinical assessment & brain imaging after return of spontaneous circulation post cardiac arrest
- Core body temperature
- Pupillary assessment
- Vestibulo-ocular reflex
- Apnea testing
- Number of clinical assessments
- Ancillary investigations
In addition, historical nomenclature has been replaced by death determination by neurologic criteria (DNC) (previously referred to as neurologic determination of death or brain death) and death determination by circulatory criteria (DCC) (previously referred to as cardiocirculatory death, or circulatory death)
The priority of all healthcare professionals is always to save life. Death determination, and subsequently organ donation, are only considered after all life-saving efforts are exhausted, and there is no chance of recovery.
The ethical foundation for deceased organ donation, which accounts for more than 80% of all organ transplants in Canada, is the dead donor rule – “vital organs should only be taken from dead patients and, correlatively, living patients must not be killed by organ retrieval.” Trust in the health care system and the practice of deceased organ donation is predicated on a clear definition of death and criteria for its determination.
Using a rigorous and standardized process of guideline development that included systematic reviews of the scientific literature and assessing the quality of the available evidence, the recommendations in the clinical practice guideline apply to potential organ donors who will undergo death determination death determination by circulatory criteria (DCC), in addition to all mechanically ventilated patients who will undergo death determination by neurologic criteria (DNC), regardless of organ donation potential.
These guidelines are intended to minimize any risk of diagnostic error and, most importantly, err on the side of caution to avoid concluding that a patient is dead if they may not be. If a clinician has any uncertainty at all, then death should not be determined.
Supporting a loved one through the dying process often places overwhelming emotional and psychological burdens on families and substitute decision makers. A multidisciplinary support team (e.g., nurses, social workers, psychologists, spiritual care advisors, religious officials, and donor coordinators where applicable) should be included in care discussions as early as possible when it is suspected that a patient may progress to death.
Specific considerations to facilitate family members understanding and acceptance of death determination by neurologic criteria, in particular, include:
- Using clear and consistent language
- Preparing families and substitute decision makers early
- Anticipate and clarify questions about how death is determined
- Repeating information
- Using multiple methods to communicate
- Inviting families and substitute decision makers to witness the death determination process
- Acknowledging that seeing a patient’s chest rise or feeling their warm body makes it difficult for families and substitute decision makers to accept death has occurred
- Understanding the acceptance of death unfolds over time rather than in one isolated meeting
- Providing opportunities for end-of-life rituals