Brain death Flashcards
What is death?
Irreversible biological event characterized by the permanent cessation of critical function of an organism as a whole
T/F: Tissues can survive in isolation after the system has died
True, but the survival of these tissues requires removal from the organ system as a whole whose integrative function has been lost
Are coma and brain death the same thing?
No
Why is brain death considered death?
Brain is central to integrated functioning of the body
Describe coma
Coma is a lack of responsiveness
Unarousable unresponsiveness
Brainstem reflexes may still work
Patient may retain a drive to breath
When does anoxic brain injury occur?
Cardiac arrest
Massive stroke
Carbon dioxide intoxication
Drug overdose
Head trauma
Is anoxic brain injury considered brain death?
No
What can cause a persistent vegetative state?
Severe anoxic brain injury
Is a persistent vegetative state considered brain death?
No
Describe how a patient in a persistent vegetative state presents
No evidence of awareness of self or environment and inabilty to interact with others
No evidence of sustained, reproducible, purposeful or voluntary behavioral responses to visual, auditory tactile or noxious stimuli
No evidence of language comprehension or expression
Intermittent wakefulness manifested by the presence of sleep wake cycles
What can a persistent vegetative state represent?
Represents a transition
Between coma and recovery
Between coma and death
Describe a minimally conscious state
Intermittent limited interactions with environment
Is a minimally conscious state brain death?
No
What behaviors might a patient in a minimally conscious state exhibit?
Visual tracking
Following simple commands
Signalling yes or no
Verbalizing intelligently
Behaving purposefully in restricted circumstances
Retain sleep wake cycles
What limitations does a patient with locked in syndrome have?
Cannot move muscle in limbs trunk or face
What can cause locked in syndrome?
Follows focal injury to the base of pons while preserving consciousness
What can a patient with locked in syndrome do?
Can voluntarily blink and move eyes vertically
What are the prerequisites required to diagnose brain death
Clinical or neuroimaging evidence of an acute central nervous system catastrophe
Exclusion of complicating medical conditions that may confound clinical assessments
No drug intoxication or poisoning including medically administered sedatives
Core temp > 36 celsius
Systolic BP > 100 mmHg even if vasopressors are required
What complicating medical conditions that may interfere with diagnosing brain death?
Disturbances of electrolytes, acid-base, endocrine or circulation (shock)
What will the pupils look like in a patient who is brain dead?
Pupils are mid position and do not respond
3.5-4 mm
What is considered a normal pupillary response?
Dilate in low light
Contract in bright light
What is a normal corneal reflex?
Move eye away from stimulus
Describe the corneal reflexes of a patient with brain death
Absent
What do normal oculocephalic reflexes look like?
Look towards the ear being filled with water
