Download - Brain death
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 !