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 المقررات بوحدة الجودة

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.

Definition: Irreversible cessation of functions of the entire brain, including the brainstem that is clinically ascertainable.

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

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.

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

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.

Drug toxicity, such as narcotics, muscle relaxants, or hypnotics. Exclusions: Reversible causes of coma must be excluded: Drug toxicity, such as narcotics, muscle relaxants, or hypnotics. Metabolic or endocrine causes 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.

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.

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.

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)

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.

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