Brain Death

Question 1

what is brain death

Answer 1

when there is no demonstrable brain stem function in the presence of a diagnosis compatible with irreversible structural brain damage

Question 2

what are the main functions of teh brain stem

Answer 2

resp drive and control of respiratoin
regulation of cardiovacular function
control of consciouness and the sleep wake cycle
all motor output from the brain passes via the brainstem
sensory input to higher centres of teh brain
CN reflexes

Question 3

what are the most common causes of brain death

Answer 3

head injury
intracerebral haemorrhage
cerebral hypoxia

Question 4

when must the diagnosis of brain death be considered

Answer 4

sustained acute severe structural which has lead to permanent coma with permanent loss of the capacity to breathe

Question 5

what are the other causes of apnoeic coma other than brain death

Answer 5

hypothermia
metabolic or endocrine causes
CNS depression by cause
exclude neuromuscular blocking agents (paralytics) as a cause of apnoea

Question 6

give 5 clinical signs of brain stem death

Answer 6

• no pupillary response to light
• absent corneal reflexes
• absent caloric responses
• no motor responses in distribution of the CN
• No cough or gag reflexes

Question 7

define apnoea

Answer 7

no attempt by the patient to breathe following ventillator disconnection despite the presence of an arterial pressure of CO2 adequate to stimulate repsiration