Determination of Brain Death

Death Determination Using Brain Criteria in the Adult

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Policy

1.1 This document establishes a uniform approach to rendering a diagnosis of death based on failure of brain function in line with MGH, state and federal regulations. This has been referred to as brain death , but must be understood to be no different than a diagnosis of death made by other criteria.

1.2 Please read this entire document before starting the process of declaration, as it contains important procedural information and identifies common pitfalls. A required checklist for the proper performance of testing is found at the end of this document.

Background

2.1 Death by brain criteria is defined under Massachusetts state law as the total and irreversible cessation of spontaneous brain functions, in which further attempts of resuscitation or continued supportive maintenance would not be successful in restoring such function. Stated more simply, brain death is the irreversible loss of all function of the brain, including the brainstem. A patient determined to be brain dead is legally and clinically dead.

2.2 The three essential findings in brain death are coma, absence of brainstem reflexes, and apnea. An evaluation for brain death should be considered in patients who have suffered a massive, irreversible brain injury of identifiable cause. Brain death from primary neurological disease is usually a result of severe head injury or cerebrovascular events. Global ischemic brain insults or fulminant hepatic failure, among other diagnoses, may also result in irreversible loss of brain function.

2.3 The diagnosis of brain death is primarily clinical. No other tests are required if a single full clinical evaluation, including an examination of brain stem reflexes and an apnea test, are conclusively performed. Ancillary testing is required only in situations in which the clinical determination is unavoidably inadequate, e.g. in cases of severe facial trauma, drug intoxication, severe metabolic disturbances or when the apnea test cannot be performed safely. In the absence of either complete clinical findings consistent with brain death , or ancillary tests demonstrating brain death , brain death cannot be diagnosed. These guidelines do not replace the physician's judgment in individual cases, since brain death is a clinical diagnosis.

2.4 For pediatric patients, refer to the policy Death: Determination using Brain Criteria in the Pediatric Population located in the Clinical Policy and Procedure Manual.

Requirements

3.1 One full exam, including apnea testing, must be performed by an attending neurologist or neurosurgeon, or a neurocritical care fellow under the supervision of a neurology attending, and documented as such.

3.2 American Academy of Neurology guidelines stipulate that a single full exam, as detailed below, is required to diagnose brain death . Like any other evaluation, the exam may be repeated after an arbitrary interval if the evaluating physician feels this is necessary.

3.3 Contacting the New England Organ Bank (1-800-446-6362) prior to any discussion with the family is mandatory for any patient who is likely to meet criteria for organ donation.

3.4 A member of the Respiratory Therapy department must be present during apnea testing.

3.5 In cases in which the process of determining death by brain criteria may be in conflict with religious, cultural or personal beliefs of the patient or the patient's family, consultation of the Medical Ethics Committee (Optimum Care Committee) may be helpful.

Prerequisites for the clinical Determination of Brain Death

4.1 The proximate cause must be known, and must be known to be irreversible. There must be clinical or neuro-imaging evidence of an acute central nervous system catastrophe that is compatible with the clinical diagnosis of death by brain criteria.

4.2 Absence of severe acid-base, electrolyte, or endocrine abnormality that may confound clinical assessment. What constitutes a "severe" abnormality is left to the judgment of the evaluating physician.

4.3 Toxicology screening negative for significant confounding substances. If barbiturates given, serum level < 10 mcg/ml. If significant doses of CNS-depressing medications (e.g. narcotics, sedatives, hypnotics, anticholinergics, etc.) have been administered recently, wait for 5 half-lives of the medication in question or, if serum levels are available, until the level is below therapeutic. Renal or hepatic dysfunction, or preceding hypothermia may prolong clearance. If high suspicion for unknown or unmeasurable CNS-depressants, consider ancillary testing

4.4 Demonstrated absence of neuromuscular blockade by electrical stimulation (e.g. with train-of-four nerve stimulation) if neuromuscular blocking agents have been administered recently or for a prolonged period

4.5 Core temperature >= 36°C (96.8°F). Temperature may be supported artificially (e.g. with a warming blanket, etc).

4.6 Stable systolic blood pressure >= 100 mmHg. BP may be supported with pressors.

In the presence of confounding variables, brain death may still be determined with the aid of ancillary tests (see Section 8 below).

The Clinical Examination

The cardinal findings in brain death are: (1) coma, (2) absence of brainstem reflexes, and (3) apnea.

1. Coma: defined as the absence of any cerebrally-mediated response to noxious stimuli including pain in all extremities (nail-bed pressure) and in the head (e.g. supraorbital or temporo-mandibular joint pressure). "Spinal" reflexes are consistent with brain death , but decorticate/decerebrate posturing are not.
2. Absence of brain stem reflexes
   • Pupils
     • No response to bright light. A magnifying glass may be useful if response is questionable.
     • Size: from mid-position (4 mm) to dilated (9 mm). Small or pinpoint pupils should alert the clinician to the possibility of narcotic intoxication (but may also be seen with pontine injury or ocular surgery/disease).
   • Ocular movement
     • No oculocephalic reflex (test only when the integrity of the cervical spine is ensured)
     • No oculovestibular reflex: deviation of the eyes to irrigation in each ear with 30-50 ml of ice water. Observe for 1 minute after irrigation and wait at least 5 minutes before testing on the opposite side. Testing may be confounded by blood or cerumen in the auditory canal, a disrupted tympanic membrane or injury to the globes or orbits. Perform otoscopy prior to calorics.
   • Facial motor response to stimulation
     • No corneal reflex to touch with a cotton swab
     • No facial grimacing to any noxious stimulation, including insertion of a Q-tip into the nares
     • Facial myokymias (from denervation of the facial nerve) are permissible
   • Pharyngeal and tracheal reflexes
     • No response to stimulation of the posterior pharynx with tongue blade
     • No coughing or significant bradyarrhythmia with bronchial suctioning

Apnea Testing

1. Prerequisites-all prerequisites above plus the following:
   1. Eucapnea (PaCO2 35-45 mmHg)
      • For patients with chronic CO2 retention (e.g., COPD, severe obesity), apnea testing may be performed with the baseline PaCO2 -if known-defined as eucapnia. Ancillary testing should be considered in such cases, especially if the baseline PaCO2 is unknown.
   2. Euvolemia
      • If the patient is requiring significant amounts of vasopressor agents for blood pressure support, or is having unstable cardiac dysrhythmias, consider ancillary testing.
2. Preparation:
   1. Place the patient on 100% oxygen and reduce positive end-expiratory pressure (PEEP) to 5 cm H2O for > 10 minutes before beginning test. Oxygen desaturation or PaO2 < 200 mmHg with these settings may indicate difficulty with apnea testing.
   2. Obtain baseline arterial blood gas
3. Procedure:
   1. Remove patient from ventilator
   2. Provide oxygen via catheter at 10 L/min to the level of the carina
   3. Watch closely for respiratory movements (defined as abdominal or chest excursions)
   4. Monitor oxygen saturation and blood pressure
   5. Draw arterial blood gas at 5 minutes and 10 minutes
4. Terminate test for:
   1. Spontaneous respirations or respiratory effort (apnea test does not support brain death )
   2. Cardiac ectopy
   3. Pulse oximetry < 90% for > 30 seconds (can retry with T-piece, CPAP 10 cm H2O, and 100% O2 at 12 L/min)
   4. Systolic blood pressure < 100 mmHg
   • If apnea test aborted due to ectopy, oxygen desaturation, or hemodynamic instability, draw an ABG and restart artificial ventilation at original settings. Consider ancillary testing.
5. Interpretation:
   1. If respiratory movements are absent and the final arterial blood gas shows: PaCO2 >= 60 mmHg OR for patients with known CO2 retention (e.g., COPD, severe obesity) > 20 mmHg increase from the pre-test baseline then apnea has been demonstrated, supporting the diagnosis of death by brain criteria.
   • If inconclusive after 10 minutes and the patient was stable for the duration of testing, the test may be repeated with the time extended to 12-15 minutes.

Clinical Observations Compatible with the Diagnosis of Brain Death

These manifestations are occasionally seen and may be misinterpreted as evidence for brain stem function.

7.1 Spontaneous 'spinal' reflexes in the limbs (not to be confused with pathologic flexion or extension responses, which are NOT consistent with brain death )

7.2 Respiratory-like movements (shoulder elevation and adduction, back arching, intercostal expansion without significant tidal volumes) that may trigger the ventilator to deliver a breath

7.3 Sweating, blushing, tachycardia

7.4 Normal blood pressure in the absence of pharmacologic support

7.5 Absence of diabetes insipidus (i.e., normal osmolar control mechanism)

7.6 Deep tendon reflexes, triple flexion responses or Babinski's reflex

7.7 Facial myokymias

Consider ancillary testing if 6.1 and/or 6.2 are observed.

Ancillary tests supporting the diagnosis of Brain Death

8.1 Conventional angiography: Contrast injected under pressure into the aortic arch. No intracerebral filling at the point of entry of either carotid or vertebral artery to the skull. The external carotid circulation is patent, and delayed filling of the superior sagittal sinus may be seen.

8.2 Nuclear flow study: scintigraphy using Technetium 99m hexamethyl propylene amine oxime (99mTc-HMPAO SPECT): No uptake of isotope in the brain parenchyma as interpreted by an attending Nuclear Medicine physician. The extracranial circulation should fill, allowing for uptake within the meninges and skull vessels.

8.3 Electroencephalography: Absence of any electrocerebral activity during at least 30 minutes of recording.

• Integrity of entire system tested by EEG technician (EKG artifact should be visible)
• Minimum of 8 scalp electrodes used
• Distance between electrodes >= 10 cm
• Interelectrode impedance between 100 and 10,000
• Sensitivity increased to at least 2 micro V
• High and low frequency filters should not be set below 30 Hz or above 1 Hz, respectively
• Electroencephalography should demonstrate lack of reactivity to intense auditory, visual, or painful somatosensory stimulation
• Absence of EEG activity must be confirmed and documented by a neurology attending

8.4 Transcranial Doppler ultrasonography: Reverberating flow or small systolic peaks in early systole without diastolic flow are consistent with brain death . The test must be performed bilaterally, as well as anteriorly and posteriorly. Complete absence of flow may not be reliable owing to inadequate transtemporal windows for insonation. Diagnosis established by intracranial examination must be confirmed by the extracranial bilateral recording of flow in the common carotid, internal carotid, and vertebral arteries.

8.5 Insufficient data exists to support the use of CT angiography, MRI, MR angiography, or somatosensory evoked potentials for brain death determination, thus these are not currently considered acceptable ancillary tests.

Medical Record Documentation

The declaration of death by brain criteria must be documented in the medical record as a death note in a manner similar to any other declaration of death and include the following:

9.1 Etiology and irreversibility of coma

9.2 Absence of motor response to pain

9.3 Absence of brain stem reflexes

9.4 Details of the apnea test, including pre and post test arterial blood gas values

9.5 Justification for ancillary testing, if performed, along with results and name of the attending physician responsible for interpretation

9.6 The date and time of declaration and the name of the attending neurologist, neuro critical care fellow or attending neurosurgeon declaring death by brain criteria

• Time of death is defined as the time apnea is confirmed (the time the final arterial blood gas is recorded) or the ancillary test is officially interpreted

9.7 Indication that the Medical Examiner was contacted if appropriate (see guidelines in the Report of Death Form)

9.8 Results of repeat neurological examinations, if performed.

The form at the end of this document is provided to assist with the documentation of brain death in the medical record. Its use is required, and it must be filed in the patient's chart after completion of brain death testing. One copy should be used for each examination performed. It is appropriate to write a brief narrative note summarizing the indications for and results of brain death testing as recorded in this document.

Selected References

1. Evidence-based guideline update: determining brain death in adults: report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2010; 74:1911-1918
2. Practice parameters for determining brain death in adults (Summary Statement). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 1995;45:1012-1014.
3. Wijdicks EFM. The diagnosis of brain death . N Engl J Med. 2001;344:1215-1221.
4. Ducrocq X, Hassler W, Moritake K et al. Consensus opinion on diagnosis of cerebral circulatory arrest using Doppler-sonography. Task Force Group on cerebral death of the Neurosonology Research Group of the World Federation of Neurology. J Neurol Sci. 1998;145-150.
5. Goudreau JL, Wijdicks EFM, Emery SF. Complications during apnea testing in the determination of brain death : Predisposing factors. Neurology. 2000;55:1045-1048.
6. Canadian Neurocritical Care Group. Guidelines for the diagnosis of brain death . Can J Neurol Sci. 1999;26:64-66.
7. Wieler H, March K, Kaisar KP et al. Tc-99 HMPAO cerebral scintigraphy: a reliable, noninvasive method for determination of brain death . Clin Nuc Med.1993;18:104-109.
8. Commonwealth of Massachusetts 105 CMR 800.003

Check list for determination of brain death

Authoring Information

Reviewed/Approved by: Department of Neurology, Critical Care Committee, Division of Neurocritical Care and Emergency Neurology, Clinical Policy and Records Committee, Medical Policy Committee

Last updated: 5/25/2011

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