The Cleveland Clinic Foundation, 2006
Background
The declaration of death demarcates a change of a human being’s condition that serves important societal functions related to obligations, respect, professionalism, duty, law, economics, and community goods. The emergence of cardiopulmonary support technologies and solid organ transplantation prompted a re-examination of the criteria for declaring death. As a result of these discussions, a set of neurological criteria is now recognized as a determination of death of a human being. Death can result from brain damage that is so severe and extensive that the brain has no function and has no potential for recovery of function. In such cases, spontaneous respiration has irreversibly ceased owing to structural brain damage, but systemic circulation and respiration are still maintained by artificial life-support. Under such circumstances, ventilatory and circulatory support may preserve the peripheral organs for a time.
The irreversible cessation of brain functions has been recognized as death in the United States through statutes, judicial decisions, and regulations. Ohio adopted the Uniform Determination of Death Act (UDDA) in 1982. The Ohio Statute states:
An individual is dead if he has sustained either irreversible cessation of circulatory and respiratory functions or irreversible cessation of all functions of the brain, including the brain stem, as determined in accordance with accepted medical standards. If the respiratory and circulatory functions of a person are being artificially sustained, under accepted medical standards a determination that death has occurred is made by a physician by observing and conducting a test to determine that the irreversible cessation of all functions of the brain has occurred.
A physician who makes a determination of death in accordance with this section and accepted medical standards is not liable for damages in any civil action or subject to prosecution in any criminal proceeding for his acts or the acts of others based on that determination.
Any person who acts in good faith in reliance on a determination of death made by a physician in accordance with this section and accepted medical standards is not liable for damages in any civil action or subject to prosecution in any criminal proceedings for his actions.
The UDDA refers to "accepted medical standards" without specifying what these standards may be. Accepted medical standards may vary from state to state and can change over time. Most published guidelines for determining death by neurological criteria have relied on the findings of prospective clinical studies. Important findings include those from the Report of the Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death and from the Collaborative Study of the National Institutes of Neurological Diseases and Stroke. Following the published guidelines assures that a patient who is still alive will not be misdiagnosed as dead. Either behavioral responses or brain stem reflexes indicate that death has not occurred; spinal reflexes may remain in the patient who is dead by neurologic criteria. A patient in a chronic vegetative state may remain in a prolonged coma indefinitely, yet not meet the criteria for death. For children special assessments may be necessary to properly apply neurological criteria for death.
Clinical Assessment
Guidelines for determining death by neurological criteria are described below. An assessment of cerebral and brain stem function is essential, including an assessment of spontaneous respiration. This determination should include two separate exams. The first exam may be conducted by any CCF physician (including resident physicians or fellows) with appropriate institutional training. The second (confirmatory) exam must be conducted by a CCF attending physician with appropriate institutional training. For children less than 10 years of age, a staff neurosurgeon, pediatric neurologist, or pediatric intensivist should be consulted.
The clinical guidelines for this assessment are summarized in the following paragraphs Guidance documents are separately available to provide specifics:
1. Absence of Cerebral Function
Clinical testing must reveal no evidence of cerebral function. Patients must be without any type of response to verbal or painful stimuli. All potentially reversible causes of coma must be reasonably ruled out including hypothermia, drug intoxication, hypotension, neuromuscular blockade, and sedating medicines. The period of observation required to confirm that the neurological criteria for death have been met will vary according to the specific clinical circumstances. A longer period is recommended when the mechanism of coma is not known or the potential for recovery is uncertain. Spinal reflexes and various spontaneous movements may persist in patients who meet neurological criteria for death.
2. Absence of Brain Stem Function
Clinical tests must also confirm the absence of brain stem reflexes. Typical tests performed include pupillary size and reactivity, cold caloric responses, corneal, oculovestibular, gag, and cough reflexes. Institutional guidelines should be consulted when a test cannot be performed because of confounding circumstances or safety . An apnea test must demonstrate an absence of all spontaneous respiratory drive.
3. Ancillary Testing
An ancillary test is mandatory only for patients in whom complete brain stem evaluation cannot be performed. Ancillary tests may include, but are not limited to, recording evidence of an absence of cortical electrical activity or imaging evidence of sustained arrested intracranial blood flow in the presence of otherwise adequate extra-cranial circulation.
