Introduction
Methods
Term | Definition |
---|---|
Activity | Physiologic properties of cells and groups of cells that can be measured by laboratory means |
Asystole—electrical | A condition characterized by the absence of electrical, and hence mechanical, activity of the heart, resulting in the absence of contractions of the myocardium and cardiac output/anterograde blood flow |
Asystole—mechanical | The absence of effective contractions of the myocardium and no cardiac output/anterograde blood flow. May occur in the presence of an organized or disorganized electrocardiac rhythm, e.g. pulseless electrical activity |
Autoresuscitation | The spontaneous resumption of heart contractions causing anterograde circulation that is not induced by cardiopulmonary resuscitation or other external assistance. Examples of heart function such as effective contractions of the myocardium leading to anterograde flow of blood through the aorta and arterial system should be distinguished from examples of heart activity such as atrial natriuretic hormone release or residual pulseless electrical activity |
Brain death | Diagnosis and confirmation of death based on the irreversible cessation of functioning of the entire brain, including the brainstem (this forum supports the movement away from this traditional and imprecise terminology in favour of the cessation of neurological function) |
Brainstem death | Diagnosis and confirmation of death based on the irreversible cessation of functioning of the brainstem, predominantly but not exclusively secondary to a supratentorial brain injury (this forum supports the movement away from this traditional and imprecise terminology in favour of the cessation of neurological function) |
Cardiac arrest | The abrupt cessation of circulation of the blood due to failure of the heart to contract effectively. Also known as cardiorespiratory arrest, cardiopulmonary arrest, or circulatory arrest |
Catastrophic brain injury leading to death | Etiologies of high severity that are common causes of brain death, such as, but not limited to, traumatic brain injury, cerebrovascular accidents, and hypoxic-ischaemic encephalopathy after resuscitated cardiac arrest Other forms of catastrophic brain injury that have any degree of residual clinical brain or brainstem function are not under consideration and may include persistent vegetative states, permanent vegetative states, anencephaly, or those conditions related to the historical concept of higher brain (cortical) death |
Cerebral electrical activity | Electrical activity of the brain, as measured using an electroencephalogram (EEG) |
Cessation | Stoppage, termination |
Circulation | Anterograde flow of blood through the aorta and arterial system |
Circulatory death determination | Diagnosis and confirmation of death based on circulatory criteria. Also known as death after cardiac arrest, or death after cardiocirculatory arrest, or death after circulatory-respiratory determination (this forum supports the movement away from this traditional and imprecise terminology in favour of the cessation of circulatory function) |
Clinical | Based on direct, measurable observation or examination of the patient |
Coma | Prolonged absence of wakefulness, awareness, and the capacity for sensory perception or responsiveness to the external environment |
Confounding conditions | Circumstances during which a diagnostic test may become unreliable and require repetition over time or application of an alternative test |
Consciousness—loss of capacity for | Lack of current or any future potential for awareness, wakefulness, interaction and capacity for sensory perception of, or responsiveness to the external environment |
Criteria—minimum | Refers to the lowest acceptable standard. The standard recommended by this forum sets the minimum clinical criteria |
Dead donor rule | A principle governing deceased donation practices stating that vital organs should only be taken from dead patients and, correlatively, living patients must not be killed by organ retrieval. This rule does not apply to, nor preclude, living donation of non-vital organs |
Death | The moment in time during the dying process when the individual passes from the state of being alive to that of being dead |
Death—concept of | An abstract, unprovable explanation of death, generally based on religious, spiritual, or philosophical beliefs |
Death—declaration of | The point in time at which a health professional, having determined that an individual is dead, formally states this finding |
Death—operational definition of | Biomedical criteria that describe the state of human death |
Death—determination of | Processes and tests required to diagnose death in accordance with established criteria |
Disintegration | Loss of intactness, solidness, or cohesion. Such loss can apply to function or to matter (tissues, etc.) |
Dying | The process whereby biological/physiological functions cease, thus moving from the state of being alive to that of being dead |
ECMO | Extracorporeal membrane oxygenation/extracorporeal oxygenation and circulation of blood deployed for life-threatening lung or heart–lung failure |
Electromechanical dissociation | A form of mechanical asystole. A rhythm frequently encountered during cardiac arrest, characterized by organized electrical activity without circulation, traditionally measured by the absence of a palpable pulse or pulsatile arterial blood pressure |
Fixed dilated pupils | Pupils in mid-position or greater and unreactive to light |
Function | In the context of organs, the primary and fundamental purpose of that organ that can be assessed by observation and examination and is necessary for sustained life. Function should be distinguished from activities, as defined by physiologic properties of cells and groups of cells that can be measured by laboratory means. Examples of brain function such as the capacity for consciousness or ability for unassisted breathing should be distinguished from examples of brain activity such as posterior pituitary antidiuretic hormone release or residual nests of neuronal electrical activity |
Integration | Combined or coordinated separate elements that provide a harmonious, interrelated whole; organized or structured so that constituent units function cooperatively |
Irreversible | Pertaining to a situation or condition that will not or cannot return or resume. In the context of death determination, there are variable definitions including: 1.Loss of function or a condition that cannot be restored by anyone under any circumstances at a time now or in the future 2.Loss of function or a condition that cannot be restored by those present at the time 3.Loss of function or a condition that will not resume and will not be restored. Also referred to as permanent |
Neuroimaging | Diagnostic brain imaging techniques to identify structural brain injury, e.g. CT scan, MRI |
Neurological death determination | Diagnosis and confirmation of death based on neurological criteria |
No effective intervention | A therapeutic intervention that is not deployed because it is not effective, not medically indicated under those circumstances, not available or accessible |
Mechanical ventilation | Assisted ventilation including bag/mask ventilation, non-invasive support e.g. BiPAP (bilevel positive airway pressure), conventional mechanical ventilation via artificial airway |
Refractory to treatment | Does not respond to intervention in a clinically meaningful manner |
Permanent | Pertaining to a situation or condition that will not return to its previous state. In the context of death determination, refers to loss of function that will not resume spontaneously and will not be restored through intervention |
Preconditions | Patient-related prerequisites that should be fulfilled prior to application of diagnostic tests |
Respiratory arrest | Cessation of breathing. In the context of death discussions, this may be primary and lead to a subsequent cardiac arrest, or it may be secondary to the loss of brainstem function |
Test | A procedure performed in diagnosis or detection |
Test—ancillary | A complementary test or an alternative test to one that otherwise, for any reason, cannot be conducted or is unreliable |
Test—clinical | A bedside test typically based on physical examination of the patient, but may include the use of a stethoscope and vital signs monitors |
Test—confirmatory | A test performed to confirm a previously conducted test |
Test—laboratory | A technical test requiring use of elaborate equipment and medical technologies, e.g. blood testing, diagnostic imaging |
Test—supplemental | A test performed in addition to an already conducted test |
Unity | The combination or arrangement of parts into a whole |
Ventricular fibrillation | A condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles that causes the cessation of circulation. Also referred to as V-fib or VF |
Vital function | Necessary for sustained life |
Findings
Neurological sequence in the dying process
Description | Minimum acceptable clinical standard | Additional testing (beyond the minimum clinical standard) | |
---|---|---|---|
N-1 | Catastrophic brain injury: continuing deterioration and progressive loss of brain function despite intervention | 1. Established etiology and/or structural lesion capable of causing death by neurological criteria 2. Reduced consciousness (as measured by GCS 3–5 or FOUR score) 3. Evidence for progressing loss of brainstem function | 1. Neuroimaging that explains the severity of brain injury 2. Repetition of clinical exams with trends 3. Demonstration of elevated intracranial pressure (ICP) by monitoring |
N-2 | Cessation of brain function | 1. Coma (excluding spinal cord mediated reflexes) 2. Absence of brainstem reflexes: •Pupils mid-position or greater and absent pupillary light reflex (fixed dilated pupils) •Corneal •Gag/pharyngeal •Cough/tracheal •Vestibulo-ocular (‘cold caloric’) •Loss of central drive to breathe NB: performance of apnoea testing should be reserved as the last test of brainstem function | None: cessation of brain function is a clinical determination |
N-3 | Cessation of brain function with no possibility to resume | 1. Preconditions fulfilled 2. Confounding conditions excluded or addressed 3. Refractory to all applied interventions 4. Intervention not available or indicated | 1. Repetition of the minimum clinical standard examination 2. Ancillary laboratory tests e.g. •Demonstration of brain blood flow or perfusion to be absent •Refractory intracranial hypertension as measured by ICP monitoring •Transcranial Doppler consistent with absent net flow velocity •Electrodiagnostic testing (e.g. EEG, absent evoked potentials) |
Circulatory sequence in the dying process
Description | Minimum acceptable clinical standard | Additional testing (beyond the minimum clinical standard) | |
---|---|---|---|
C-1 | Cessation of circulation and breathing | 1. Absent palpable pulse 2. Absent breath sounds 3. Absent heart sounds 4. Absent respiratory effort or chest wall motion 5. Loss of pulsatile arterial blood pressure by non-invasive measurement 6. Coma and fixed dilated pupils 7. Electrical asystole is not required (pulseless electrical activity is acceptable) | 1. Loss of pulsatile arterial blood pressure by arterial line monitoring 2. Absence of anterograde blood flow through the aortic valve on echocardiography 3. Isoelectric ECG 4. Absence of pulse by Doppler NB: oxygen saturation pulse oximetry is an unreliable indicator of absence of pulsatile circulation |
C-2 | Cessation of circulation and breathing with no possibility to resume spontaneously | 1. The persistence of C-1 criteria over a period of time as confirmed by continuous observation and intermittent confirmation including repetition of this evaluation at the end of the period. The time period required is 2–5 min 2. When breathing and circulation cease following terminated CPR, the time period to reach the point of “no possibility to resume spontaneously” is 2–10 min | 1. Use of the same tests for a higher clinical/laboratory standard for C-1 applied after the time interval required to progress from C-1 to C-2 (2–10 min following termination of CPR) |
C-3 | Cessation of circulation and breathing with no possibility to resume | 1. When CPR will not be provided (patient fulfils criteria for not providing CPR) C-3 occurs at the moment of C-2 2. Following termination of CPR, including a decision not to reinstitute CPR, C-3 and C-2 occur at the same time | 1. Nothing in addition to those tests required for C-2 |