week 7

Question 1

compare and contrast the patho of primary and secondary head injury

Answer 1

primary = wack - the initial insult (e.g. head hitting windscreen)
Secondary = anything that can cause further damage that is not the primary injuiry
extracranial = hypoglycaemia, hypoxia, hypotension
intracranial = swelling, infection, haemorrage

cycle of death:
brain bleed -> cellular hypoxia -> cell death -> swelling -> inc. ICP -> worsening hypoxia -> cell death…
-> brain hernation = most likely death

Question 2

explore the relationship of the monro-kellie doctrine to traumatic brain injury

Answer 2

monro-kellie = cranial compartment isn’t elastic - therefore the sum volumes of the brain, CFS, and blood is constant 80:10:10
if there is any space occupying mass (bleed, tumour, mass) = compression and displacement of cranial contents. First CSF, then venous blood, arterial blood, then brain contents down the foramen magnum.
Once brain content goes down foramen, you see cushings triad (conning) = bradycardia, hypertension and irregular resp. rate (cheyne stokes)

Question 3

outline the clinical diagnosis and current management pathways for traumatic brain injury

Answer 3

Clical diagnosis:
any patient (especially elderly) with a fall w/headstrike on anticoagulants = hospital!
Can use ROSIER to assess
mechanism of injury
LOC
bruising, bumps, lacs
CSF coming out of ears and nose
is there any secondary injuries currently in play

Treatment:
hospital
high flow o2 (hypoxia prevention)
fluid to maintain MAP 90 or 120/systolic and GCS above 8
IV glucose (where necassary)
posturing - 30% head up to decrease ICP (even in precense of spinal injury)
20mins max scene time
ondansatron - to keep airway clear and because vomiting increases ICP
NO C COLLAR!
seizure management - dont wait before administering midaz

Question 4

describe the principle of cerebral autoregulation

Answer 4

baroreceptors are constantly monitering systemic BP and provide a negative feedback loop
cerebral autoregulation:
MAP = mean arterial pressure
CPP = cerebral perfusion pressure
ICP = intracranial pressure
CPP = MAP - ICP

as MAP increases = arteries constrict
as MAP decreases = arteries dilate

MAP below 50 = passive collapse
MAP above 150 = maximum constriction

when artieres in the brain are dilating, arteries in the peripheries are constricting - visa versa

Question 5

describe the signs and symptoms of potential TBI patient

Answer 5

ROSIER
LOC
cognitive impairement
seizures
any secondary survey findings
lightheadness
headache
NV
photophobia

Question 6

outline the main risk factors for TBI and their implications for the prehospital falls assessment in the elderly

Answer 6

risk factors for TBI:
Mechanism
Anticoagulants
age
any elderly patient in the nursing homes on anticoauglants must be taken to hospital for review
- atrophy of the brain from dementia, etc.