Brain Death

1. Brain Death د/ عبد المنعم جودة مدبولى دكتوراة الطب الشرعي و السموم الإكلينيكية, مدرس الطب الشرعي و السموم الإكلينيكية, استشاري علاج التسمم بمستشفى بنها الجامعي عضو لجنة مراجعة البرامج و المقرراتبوحدة الجودة

2. Brain Death Objectives: Concept of brain death. Definition. Types of brain death. Causes of brain death. Diagnosis of brain death. Medico-legal implications of brain death.

3. Definition: Irreversible cessation of functions of the entire brain, including the brainstemthat is clinically ascertainable.

4. Types: • Cortical death(persistent vegetative state = PVS = coma prolonged. • Brain stem death(coma depasse). • Whole brain death= 2.

5. Causes: Causes outside brain (2nd brain death): • Due to respiratory and cardiac arrest. • It equated to somatic death. • No medical or legal or religious problems. Causes within the brain (1ry brain death): • Due to structural brain damage that cause brain stem death. • It includes, head trauma, poisoning and other brain lesions (tumor). • There are medical, legal and religious problems.

6. Diagnosis: • Preconditions: • Patients selection. • Doctor selection. • Time of examination. • Exclusions. • Diagnostic criteria. • Repeat examination. • Medico-legal Implications.

7. Preconditions: Patients selection: • The diagnosis must give an etiology that confirms that the damage is irreversible (irremediable structural brain damage). • The patient must be in unresponsive apnic coma, though spinal reflexes do not exclude the diagnosis.

8. Exclusions: • Reversible causes of coma must be excluded: • Drug toxicity, such as narcotics, muscle relaxants, or hypnotics. • Metabolic or endocrinecauses such as hypoglycaemia, hyperglycaemia, hyponatraemia, hepatic failure, uraemia, myxoedema, or Reye's syndrome. • Hypothermia there is no fixed recommendation, but testing should be done at higher than 35°C.

9. Diagnostic criteria: • Coma with flat EEG. • Absence of brainstem reflexes: - Barany’s test (Vestibulo-ocular R.) - Doll’s = Cantellis sign (Oculocephalic R.) • Absence of spontaneous respiration (Apnoea test). + • Confirmatory tests of brain death.

10. Apnea testing: • At the beginning, the ventilator should be set to deliver 100 per cent oxygen (for more than 10 min). • A blood gas may be taken. • The patient is disconnected from the ventilator and oxygen is insufflated via a catheter into the tracheal tube. • In apnea the PaCO2 rises at between only 0.5 and 1 kPa/min. • Careful observation of the patient for respiratory movements during the disconnection continues until a blood gas shows that the PaCO2 has risen to more than 7 kPa (just over 50 mmHg). • Oxygenation is usually well maintained. • The patient is usually reconnected to the ventilator once the target PaCO2 is reached if this is the first testing, or if organ donation is planned.

11. Repeat examination: • A second testing is done at a later time • To remove the risk of observer error. • The interval between the tests is not fixed, but usually between 1 and 6 h (few hs)

12. Medicolegal implications: I- Harvesting of organs: • Informed consent: • Patient while being healthy. • Family. • Forensic pathologist. • After harvesting organs machine is off and death is declared.

13. II- Maintenance or removal of life support: • Made by treating doctors not transplanting doctors, depending on: • Human dignity. • Family distress. • Practical need for ICU.