Chapter 6- Head Trauma Flashcards
should obtaining a CT scan in a head injury delay transfer to a trauma center?
No, patient should be transferred to a trauma center capable to definitive neurosurgical intervention as first priority
Things to include in OCP of patient with TBI
Age MOI and time BP and Oxygen saturation GCS score, emphasis on motor response/ pupils focal neuro deficits associated injuries results of CT scan treatment of HPOTN/ hypoxia
what fossa houses the frontal lobe
anterior fossa
what fossa houses the temporal lobes
middle fossa
what fossa houses the lower brain stem and cerebellum
posterior
what are the three layers of the meninges
dura mater
arachnoid mater
pia mater
meningeal layer that adheres firmly to the internal surface of the skull
dura mater
layer that is firmly attached to teh brain
pia mater
what fills the space between the arachnoid mater and pia mater
cerebrospinal fluid (CSF)
what separates the hemispheres
falx cerebri
which side of the brain typically contains the language center
left hemisphere
contained in the midbrain and upper pons, responsible for the state of alertness
reticular activating system
where is the vital cardiorespiratory center
medulla
this divides the intracranial cavity into the supratentorial and infratentorial compartments
tentorium cerebelli
what type of herniation may compress the oculomotor nerve which may lead to pupillary dilation (blown pupil)
temporal lobe herniation
part of the brain that usually herniates through the tenorial notch
medial part of the temporal lube (uncus)
classic sign of uncal herniation
ipsilateral pupillary dilation and contralateral hemiparesis
What is the normal ICp at resting state
10 mm Hg. Pressures >20 mm Hg are associated w/ poor outcomes
states that the total volume of the intracrnail contents must remain constant because the cranium is a rigid, nonexpansible container
monro-kellie doctrine
CPP (cerebral perfusion pressure) =
MAP- ICP
What MAP is “autoregulated” to maintain constant cerebral blood flow
50-150
GCS score associated w/ coma or severe brain injury
8 or less
GCS for a moderate brain injury
9-12
GCS for minor brain injury
13-15
Max GCS score for eye opening
4 (spontaneous)
eye GCS score for opening eyes to pain
2
eye GCS score for opening eye to speech
3
eye GCS score for no eye opening
1
Verbal GCS score for confused conversation
4
Verbal GCS score for inappropriate words
3
verbal GCS score for no speech
1
verbal GCS score for incomprehensible sounds
2
verbal GCS score for oriented
5
motor GCS score for extension (Decerebrate)
2
motor GCS score for localizes pain
5
motor GCS score for flexion withdrawal to pain
4
motors GCS for abnormal flexion (decorticate)
3
Biconvex or leticular hematoma that push adherent dura away from inner table of the skull. Often in temporal region
Epidural hematoma
are subdural or epidural hematomas more common
subdural
where do the majority of cerebral contusions occur
frontal and temporal lobes
why do patients with cerebral contusions need repeat CT scans w/i 24 hours
evolve to form an intracerebral hematoma and have a mass effect so they may need surgical evacuation
History of disorientation, amnesia, or transient loss of consciousness.
minor brain injury (GCS 13-15)
amnesia before the event
retrograde
amnesia after the even
anterograde
Whom should CT scan be obtained in with minor brain injury
open skull fracture, sign of basilar skull fracture, >2 episodes of vomiting, >65 years old, LOC > 5 minutes, retrograde amnesia for >30 minutes, severe HA, focal neuro deficit
Are patients with a GCS of 9-12 discharge home?
No, they should be admitted to the ICU and ahve frequent repeat neuro checks and consider f/u CT in 24 hours
One thing to especially monitor with moderate brain injury
airway/ breathing- can have hypoventilation. want to avoid hypercapnia. may need to intubate if they deteriorate
patient is unable to follow simple commands
severe brain injury (GCS 3-8)
priorities with severe brain injury
ABCDEs
once BP normal- GCS and pupillary rxn
Establish cause of HPOTN if not >100 (may need laparotomy- CT after this/ or Burr hole in OR)
Can intracranial hemorrhage cause hemorrhagic shock?
No
What should be done prior to sedating a patient with a brain injury
GCS score and pupillary exam
What is a well known early sign of temporal lobe (uncal) herniation
dilation of the pupil and loss of pupillary response to light
A shift of ___ mm or greater on head CT is often indicative of the need for surgery to evacuate the blood clot or contusion causing the shift
5 mm
medical therapies for brain injuries
IV fluids, temporary hyperventilation, mannitol, hypertonic saline, barbiturates, anticonvulsants
what type IV fluids should be used in a TBI
ringer’s lactate or normal saline
what is the preferable level for PaCO2
35 mm Hg (low end of normal which is 35-45) a this promotes vasoconstriction
how does hyperventilation help
will low ICP in a deteriorating patient with expanding intracranial hematoma until emergent craniotomy can be performed
indications for administration of mannitol in a euvolemic patient
acute neuro deterioration (dilated pupil, hemiparesis, LOC)
how much mannitol should be given
1g/kg bolus over 5 minutes then transport patient to CT or OR
What is mannitol used for?
reduce elevated ICP
why can’t mannitol be given to patients with hypotnesion
it doesn’t lower ICP w/ hypovolemia and is a potent osmotic diuretic
Preferable agent to reduce ICP in a hypotensive patient
hypertonic saline
used when need to reduce ICP when other methods are ineffective
barbiturates
when should barbiturates not be used
presence of hypovolemia or hpotn
why are barbiturates rarely used
lead to HPOTN
long 1/2 life
prolong time to brain death determination
why should anticonvulsants only be used when necessary
may inhibit brain recovery
early anticonvulsant doesn’t change long term seizure outcome
agents of choice in acute phase of seizures
phenytoin and fosphenytoin (Loading dose is 1 g phenytoin IV no faster than 50 mg/min)
phenytoin maintence dose
100 mg/8 hours
meds frequently used in addition to phenytoin until seizure stops
diazepam or lorazepam
Do muscle relaxants (like succinylcholine or vecuronium) control seizures?
No, the only mask the tonic/ clonic aspect of them. try to control seizures before initiating these drugs
What does CSF leakage with a scalp wound indiate
there is a dural tear
tx for depressed skull fractures
operative elevation if depression is greater than the thickness of the adjacent skull
Brain death
GCS=3
nonreactive pupils
absent oculocephaic, corneal, doll’s eyes, no gag reflex
no spontaneous ventilatory effort
what are the C’s of increased density on head CT
contrast, clot, cellularity (tumor), calcification (pineal gland, choroid plexus)
