Braindeath Flashcards
What characterises a coma?
- Patient’s eyes don’t open either spontaneously or to external stimulation
- Patient does not follow any commands
- Does not mouth or utter recognisable words
- Patient doesn’t demonstrate intentional movement
- Patient cannot sustain visual pursuit movement of the eyes in any direction when the eyes are held open manually
The above criteria is not secondary to use of paralytic agents
What is the Glasgow Coma Scale (GCS)?
The most common scoring system used to describe the level of consciousness in a person
What does the GCS measure?
Eye opening (E): 4 = spontaneous 3 = to sound 2 = to pressure 1 = none NT = not testable
Verbal response (V): 5 = orientated 4 = confused 3 = words, but not coherent 2 = sounds, but no words 1 = none NT = not testable
Motor response (M): 6 = obeys command 5 = localizing 4 = normal flexion 3 = abnormal flexion 2 = extension 1 = none NT = not testable
What is locked in syndrome?
A rare neurological disorder characterised by complete paralysis of voluntary muscles, except for those that control the eyes. People with locked-in syndrome are conscious and can think and reason, but are unable to speak or move. Vertical eye movements and blinking can be used to communicate.
Tends to affect around 1% of people who have a brainstem stroke.
Can you recover from locked in syndrome?
It is a condition for which there is no treatment or cure, and it is extremely rare for patients to recover any significant motor functions. About 90% die within four months of its onset.
What is the maximum possible score for GCS?
15
What causes locked in syndrome?
Damage to ventral pons (usually caused by brainstem stroke)
Why are vertical eye movements spared in locked in syndrome?
Midbrain is spared
What is a vegetative state?
No evidence of:
- Awareness of self or environment or ability to interact with others
- Sustained purposeful or voluntary behaviours either spontaneously or in response to stimuli in any sensory modality
- Language, comprehension or meaningful expression
Reflexive, automatic and spontaneous behaviours may be observed
When is a persistent vegetative state diagnosed?
Diagnosed if no change at 30 days
50% chance of improvement within 6 months, though the vast majority remain severely disabled
What is wakefulness?
Activity of reticular activating substance from the brainstem
A daily recurring brain state and state of consciousness in which an individual is conscious and engages in coherent cognitive and behavioural responses to the external world.
What does consciousness require?
Both wakefulness and awareness
What is a minimally conscious state (MCS)?
Severely altered consciousness. Reproducible but inconsistent intentional/purposeful behavioural responses.
A person who shows clear but minimal or inconsistent awareness is classified as being in a minimally conscious state.
They may have periods where they can communicate or respond to commands, such as moving a finger when asked.
Injury to which part of the brain causes a vegetative state?
- Destruction of cortex and hemispheres
- Intact ascending reticular activating substance
What is the reticular activating system (RAS)?
a set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and sleep-wake transitions.
