Brain Death

Dr. Abhijeet DeshmukhDept. of PediatricsPushpagiri Institute of Medical Sciences & RCTiruvalla , Kerala.

• Definition: The irreversible cessation of all functions

of the entire brain, including the brainstem. also known as the determination of

death using neurologic criteria

Diagnostic Guidelines

• For children - published in 1987 by a Special Task Force to the American Academy of Pediatrics (Not revised yet)

• For adults - by the American Academy of Neurology in 1995.

Clinical diagnosis

• Key components :

1. Demonstrations of irreversible coma/unresponsiveness,

2. Absence of brainstem reflexes

3. Apnea

• Before diagnosis of B.D, rule out cause of the coma by historical, radiologic, and laboratory data to rule out a reversible condition.

• Causes of irreversible coma :Severe head injury,hypertensive intracerebral hemorrhage,

aneurysmal subarachnoid hemorrhage, hypoxic-ischemic brain insults and fulminant hepatic failure.

• Causes of reversible coma : metabolic disorders, toxins, sedative drugs, paralytic agents, hypothermia, hypoxia, hypotension/shock, hypoglycemia/hyperglycemia, hyponatremia/hypernatremia, hypercalcemia,

hypermagnesemia, nonconvulsive status epilepticus, hypothyroidism, hypocortisolism, hypercarbia, liver or renal failure, sepsis, meningitis, encephalitis, SAH, surgically remediable brainstem lesions

• Apnea : clinically confirmed through the apnea test.

• performed only if the first 2 criteria for brain death(irreversible coma and absence of brainstem reflexes) are already confirmed.

• Procedure : Preoxygenate the patient with 100% oxygen for approximately 10 min

adjust ventilation to achieve a PCO2 of about 40 mm Hg

• During the test, oxygenation is maintained on CPAP and 100% oxygen by means of the ventilator circuit or a resuscitation bag such as a Mapleson device,

• Child is assessed for breathing efforts through observation and auscultation.

• A blood gas sample is obtained approximately 10 min into the test and every 5 min thereafter until the target PCO2is surpassed; ventilatory support is resumed at that time.

• If at any point during the test the patient becomes hypoxic or hypotensive, the test is aborted and ventilatory support is resumed.

• Absence of respiratory efforts with a PCO2 > 60 mm Hg or more than 20 mm Hg above an elevated baseline value is consistent with brain death.

Observation Period

Varies by age :•  7 days- 2 mo:

2 examinations separated by at least 48 hr.• 2 mo - 1 yr :

2 examinations separated by at least 24 hr are recommended.

• >1 yr :

12-hr observation period between exams.

If the cause of the coma is hypoxic-ischemic brain injury and the first exam is performed shortly after the insult, a period of at least 24 hr is recommended before the second exam.

A second exam is not needed if a nuclear medicine cerebral flow scan demonstrates absence of CBF.

Confirmatory Tests

•  All children <1 yr of age. • Where clinical exam is impossible to perform

or the results are suspected to be unreliable.• The 2 most commonly used confirmatory

tests are :

- EEG and

- Studies to confirm the absence of CBF

eg. nuclear medicine cerebral flow scans.

•  An EEG showing electrocerebral silence over a 30-min supports the diagnosis of brain death.

•  Advantages : wide availability and low risk.

• Disadvantages : artefact in the presence of drugs like barbiturates

•  Nuclear medicine cerebral flow scan :

Intravenous injection of a radiopharmaceutical agent followed by imaging of the brain

Absence of uptake in the brain demonstrates absence of CBF and is confirmatory of brain death

Advantages : low risk, not affected by drug levels.

Documentation

1   Etiology and irreversibility of the coma2   Absence of confounding factors: hypothermia, hypotension, hypoxia, significant metabolic derangement, significant drug levels

  3   Absence of motor response to noxious stimulation4   Absence of brainstem reflexes: pupillary light reflex, oculocephalic/oculovestibular reflex, corneal reflex, cough and gag reflex5   Absence of respiratory effort in response to an adequate stimulus; blood gas values should be documented at the beginning and end of the apnea test

Supportive Care

• supportive care may continue for hours to days as the family makes decisions about potential organ donation and comes to terms with the diagnosis.

• Refereance –Nelson Textbook of Pediatrics 19 th edition.

Thank You !