Policy on Brain Death

The Cleveland Clinic Foundation, January, 2001

Background

Brain death results from brain damage that is so severe and extensive that the brain has no potential for recovery. Spontaneous respiration has irreversibly ceased owing to structural brain damage, but the systemic circulation is still maintained by artificial life-support. Ventilatory and circulatory support may preserve the peripheral organs for a time under such circumstances, but the heart will stop within a few days or, rarely, after several weeks. The medical profession generally agrees that the death of the brain is an appropriate determination of death of a human being.

The concept that death can be defined as the irreversible cessation of brain functions is universally recognized in the United States through statutes, judicial decisions, or regulations. Ohio adopted the Uniform Determination of Death Act 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 Uniform Act 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 brain death 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. These studies indicate that a patient will not survive with irreversible coma, apnea, absence of brain stem reflexes, and an isoelectric electroencephalogram (EEG) that persists for 6 hours after the onset of coma and apnea.

Following the published guidelines assures that a patient who is still alive will not be misdiagnosed as dead. The patient in coma with some remaining brain-related bodily functions is not dead. Either behavioral responses or brain stem reflexes indicate that brain death has not occurred. A patient in a chronic vegetative state may remain in a prolonged coma indefinitely, yet not meet the criteria for brain death. For children less than 1 year of age, special assessments may be necessary.

Clinical Assessment

Guidelines for determining brain death are described below. An assessment of cerebral and brain stem function is essential, including an assessment of spontaneous respiration. It is strongly recommended that a staff neurologist or a staff neurosurgeon be consulted. For children less than 10 years of age, it is strongly recommended that a staff pediatric neurologist, neurosurgeon or pediatric intensivist should be consulted.

The clinical guidelines for this assessment are summarized in the following paragraphs:

1. Absence of Cerebral Function

Essential to the diagnosis of brain death is that the cause of coma be known. Clinical testing must reveal no evidence of cerebral function. Patients must be in a deep coma without any response to verbal or painful stimuli. All reversible causes of coma must be ruled out including hypothermia (core body temperature less than 33° C), drug intoxication, hypotension, neuromuscular blockade, and sedating medicines. The period of observation required to confirm the diagnosis of brain death will vary according to the specific clinical circumstances. A longer period is recommended when the cause of coma is not known or the potential for recovery is uncertain. Spinal reflexes, various spontaneous movements, and specific posturing may persist in patients with brain death.

A confirmatory test may be attempted for patients in whom clinical testing is consistent with brain death. A confirmatory test is mandatory for patients in whom complete brain stem evaluation cannot be performed. Confirmatory tests may include transcranial Doppler ultrasonography, electroencephalogram (EEG), cerebral angiography, and isotope angiography.

An isoelectric EEG is not mandatory, but when used in conjunction with the clinical criteria for brain death, it provides confirmatory evidence of brain death. Because hypothermia or drug intoxication can also produce an isoelectric EEG, this test cannot be used as the sole criterion for the diagnosis of brain death.

2. Absence of Brain Stem Function

Clinical tests must also confirm the absence of all brain stem reflexes including pupillary size and reactivity, and corneal, oculovestibular, gag, and cough reflexes. An apnea test must demonstrate an absence of all spontaneous respiratory drive. It is recommended that physicians familiar with the performance of this test be consulted when appropriate. There must be apnea long enough for the PaCO2 to become greater than 60 mm Hg in the absence of metabolic alkalosis. The test of absent breathing should be performed following hyperoxygenation on 100% oxygen on mechanical ventilation. Adequate circulation should be maintained during the entire apnea test.

Brain Death Policy: Approved by Ethics Committee Jan. 17, 2001
Presented to BOG on Jan. 24, 2001
Minor revisions suggested by BOG, accepted by EC
Approved by BOG, with revisions, Jan. 24, 2001

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