Table 4 Summary of prerequisites, diagnosis, and ancillary tests for brain death/death by neurologic criteria
From: Brain death: a review
Prerequisites for BD/DNC | |
|---|---|
Evident Etiology | -Establish that patient has a known diagnosis that has resulted in irreversible coma -Exclude mimicking conditions -Establish that brain injury is irreversible -Neuroimaging should demonstrate evidence of an acute central nervous system injury consistent with the profound loss of brain function |
Observation period before the (first) Neurologic examination | Minimum of 24 h after resuscitated cardiac arrest, rewarming after therapeutic hypothermia or birth asphyxia |
Temperature, Blood pressure |  ≥ 36 °C, Systolic blood pressure ≥ 100 mm Hg or mean arterial pressure ≥ 60 mm Hg in adults and age-appropriate in pediatric patients |
Intoxication | -Exclude intoxication by any substance that can depress the central nervous system by drug screen, ensuring serum level does not exceed the therapeutic range, and waiting at least 5 half-lives, taking hepatic or renal dysfunction into consideration -Exclude pharmacologic paralysis with a peripheral nerve stimulator |
Laboratory tests | Exclude severe electrolyte, acid base, and endocrine disturbance |
Diagnostic tests | |
-Number of examinations -Number and Qualifications of examiners | -One in adults and two in pediatric patients -One Practitioner who have completed training, licensed to independently practice medicine, and trained in determination of BD/DNC, counseling families at end of life, and managing devastating brain injuries. Pediatric patients should be evaluated by experienced pediatric clinicians with specialty in neonatology, neurosurgery, pediatric critical care, pediatric neurointensive care, pediatric neurology, or trauma surgery. One in adults and two in pediatric patients |
Items of clinical examination | Exam. for unresponsiveness Exam. for absence of motor response of face/extremities Exam. for absence of pupillary light reflex Exam. for absence of oculocephalic and oculovestibular reflexes Exam. for absence of corneal reflex Exam. for absence of gag and cough reflexes Exam. for absence of sucking and rooting reflexes(neonates) |
Ancillary testing | |
Indications | -Components of the examination cannot be completed because of the underlying medical condition -Uncertainty regarding interpretation of spinal-mediated motor reflexes -High cervical spine injury -Uncertainty about drug elimination -Severe metabolic, acid–base, or endocrine derangements that cannot be corrected and are judged to potentially be contributing to loss of brain function -The whole-brain death formulation is being followed and there is isolated brainstem pathology Law/regional guidance mandates ancillary testing |
Recognized Tests | -Four-vessel catheter angiography -Radionuclide cerebral blood flow scan -Transcranial Doppler (adults only) -EEG only if mandated by regional law or policy or if craniovascular impedance has been affected by open skull fracture, decompressive craniectomy, or an open fontanelle/ sutures, in which case it should be performed in conjunction with somatosensory and brainstem auditory evoked potentials |
Apnea testing | |
Contraindications | -High cervical spine injury -Chronic hypoxemia due to cyanotic heart disease |
Apnea testing target | -pH < 7.3 and PaCO2 ≥ 60 mm Hg unless the patient has preexisting hypercapnia, in which case target should be ≥ 20 mm Hg above baseline, if known |
When to abort testing | -Spontaneous respirations witnessed -Systolic blood pressure < 100 mm Hg or mean arterial pressure < 60 mm Hg -Sustained oxygen desaturation < 85% -Unstable arrhythmia |
Number and Technique | -One in adults and two in pediatric Patients -Preoxygenate for at least 10 min with 100% oxygen -Ensure PaCO2 35–45 mm Hg -Preserve oxygenation with an insufflation catheter placed through the endotracheal tube (except in neonates, infants, or young children) -Consider use of CPAP on the ventilator or via resuscitation bag |