Neuro Flashcards
What makes up the CNS
brain
spinal cord
CN I and II
what do sensory neurons inervate
skin muscle joints viscera provide sensory info to CNS
what are the nerves of the PNS separated into
sensory
motor
what do motor nerves innervate
skeletal muscle (somatic) and ANS
what are the two components of the autonomic nervous system
sympathetic
parasympathetic
T or F the SNS and PNS work together
false
they work in opposition to one another
how many cranial nerves are there? how many spinal nerves are there
12
13
are the cranial and spinal nerves part of the CNS or PNS?
predominantly PNS
exception: CN I and II are part of CNS
What is cranial nerve II? what is it’s function?
Optic (part of the CNS)
Function: vision, detection of light
How do we test CN II
read eye chart
detect objects/movement from corner of eyes
shine light into pupil
what is CN III? what is it’s fn?
oculomotor
Function: eye movement (up, down and in)
pupil dilation and constriction
raise eyelids
how do we test CN III
ask person to follow moving target
pupil response to light
check for ptsosis (drooping)
What is CN IX? what is its function?
Glossopharyngeal
Function: swallowing, gag reflex, speech
What is cranial nerve X? what is its fn?
vagus
swallowing, gag reflex and speech; control of muscle in internal organs
How do you test CN IX and X
ask person to swallow
say aah to check movement
have pt speak and cough - ability to protect airway
are reflexes part of the CNS or PNS
PNS
do reflexes involve the brain
no
what are the 5 components of a reflex arc
receptor - sensory fibers sensitive to stimulus
sensory neuron- afferent neuron relays impulse via posterior/dorsal root of spinal cord
interneuron - connecting center within CNS
Motor neuron - efferent neuron that relays impulse via anterior/ventral root of spinal cord to effector organ
effector- specific organ that responds
What is the brainstem composed of (5)
midbrain pons medulla reticular formation RAS
What is responsible for involuntary actions such as HR, RR, BP
brainstem
what is the area where the motor fibers cross? What kind of findings do we see below this area
brainstem
changes on contralateral side
What is the pons
relay center btw cerebellum and cerebrum
where does the brainstem connect to the spinal cord
through the foramen magnum to become the medulla
what makes up the cerebrum
cerebral hemispheres diencephalon thalamus hypothalamus basal ganglia
what makes up the diencephalon
thalamus
hypothalamus
basal ganglia
Where are CN I and II rooted
cerebrum
What are the 4 lobes of the brain
Frontal
parietal
temporal
occipital
What is the fn of the frontal lobe
high level cognitive fn personality behavior emotions motor control of speech (Broccas area) control of voluntary motor fxn
what is the fn of the parietal lobe
interprets sensory info
position
visuospatial processing
what is the fn of the temporal lobe
auditory (Wernicke's area) smell complex stimuli (e.g. faces) memory speech
what is the fn of the occiptal lobe
visual perception
smooth eye movement
sight
What is the fn of the cerebellum
control of fine movement
coordination and balance
proprioception
What is the name of the fold of dura that separates cerebellum and occipital lobe? What area of the brain is this located?
tentorium cerebella –> located in cerebellum
What is the tentorium cerebella
fold of dura that separates cerebellum and occipital lobe
encloses process/plate of skull
what CN can be affected by the tentorium cerebella
III; if ICP increases it can cause the brain to herniate through the tentorium as it is a hard structure putting pressure on CN III
Where is the reticular formation located? What is its function
core brainstem
sensation, movement, reflexive behaviors, consciousness
Where is the reticular activating system located
located in the ascending reticular formation
what is the function of the reticular activating system in the brainstem
sleep and wakefullness
what is the fn of the reticular activing system in the thalamic region
cognition and attention
what is the thalamus part of? where is it located
diencephalon
below cerebral cortex - mass of gray matter
what is the fn of the thalamus
gatekeeper for motor/sensory stimuli
what is the hypothalamus part of? where is it located
diencephalon
response to emotion maintain homeostasis via ANS and endocrine temp regulation food/water intake hormone release
Where is the basal ganglia located? what does it do?
white matter of cerebral hemispheres
integrates movement and involuntary motor fn
What bones are frequently involved in basal skull #s
sphenoid, ethmoid, temporal bones
what are the three layers of the meninges from innermost to outmost
Pia mater
Arachnoid mater
Dura mater
T or F the Pia mater adheres to the brain
yes
what are 2 characteristics of pia mater
embedded in brain structure and ventricles
rich in small blood vessels
what is the fn of pia mater
production of CSF in choroid plexus in lateral 3rd and 4th ventricles
where is the subarachnoid space? what does is its purpose
btw pia mater and arachnoid mater
contains CSF - cushins/shock absorption
What are 3 characteristics of arachnoid mater
delicate, fragile membrane thin spider like
contains vascular supply
looseley surrpound brain btwn pia and dura
what is the fn of arachnoid mater
absorption of CSF via arachnoid villi into venous sinuses
what type of blood flow occurs in a subarachnoid hemorrhage? where does it occur
arterial
subarachnoid space
what type of blood flow is involved in a subdural hematoma
venous
subdural space
what are 3 characteristics fo dura mater
forms tentorium
double-layered
tough fibrous membrane
what is the fn of dura mater
support nerves and vasculature
venous sinus for CSF drainage
where is the epidural space
space btwn skull and dura mater
what type of blood is involved in an epidural hemorrhage
arterial
what is CSF
cerebral spinal fluid
clear colorless solution that fills ventricles and subarachnoid space of spinal cord
what is the purpose of CSF
acts as shock absorber against injury
where is CSF produced
choroid plexus in 3rd and 4th ventricle
how much CSF is produced a day
~500 mL
what is the amount of CSF circulating in the ventricle system
125-150 mL
What is monro’s Foramen
small opening that connects lateral/3rd and 4th ventricle
what is munro’s foramen used for
landmark for levelling EVDs
where is the common lumbar puncture site
btw L4 and L5
What is the BBB
network of endothelial cells and astrocytes that prevent substances from reaching the brain
endothelial cells which for tight junctions w astrocytes
What does the BBB do
regulates transport of nutrients, ions, water and waste through selective permeability
what must drugs be to pass the BBB
lipid soluble
what is the BBB very permeable to
H2O O2 CO2 glucose lipid soluble compounds
T or F blood flow rates do not directly correspond to metabolism of cerebral tissue
false
blood flow rates respond directly to metabolsim of cerebral tissu - parts that are the busiest receive the most blood flow
what percentage of CO does the brain receive
~20%
Does the brain have a reserve of O2 or glucose
no
where does cerebral blood supply stem from
aortic arch
cerebral blood supply stems from the aoritc arch as pair vessels and branches into what
anterior circulation via L & R carotid arteries
posterior circulation via L and R vertebral arteries
The L and R carotid arteries bifurcate into what
external and internal carotid arteries
what do the external carotids supply
face
scalp
extra-cranial structures
what do the internal carotids supply
most of the brain
anterior circulation provides what percentage of blood flow to cerebral hemisphers
80%
What is anterior circulation comprised of
rt and left carotids which bifurcate into the internal and external carotids
where does posterior circulation originate from
subclavian artery
what does the subclavian artery lead into
R & L vertebral artery
what are the components of the posterior circulation
subclavian –> L&R vertebral –> basilar artery –> two main posterior inferior cerebellar arteries (PICA)
What does posterior circulation supply
cerebellum, brainstem, spinal cord, occipital/temporal lobes, posterior diencephalon
what blood vessels unite at the circle of willis
branches of basilar and internal carotid arteries
What arteries make up the circle of willis
2 anterior cerebral arteries - connect by anterior communicating artery
middle cerebral arteries - connect directly to anterior and posterior cerebral arteries (via communicating arteries)
What is the circle of Willis?
interconnecting network allowing blood to circulate btw hemispheres and from anterior/posterior parts of the brain
T or F the cirlce of willis allows for some degree of collateral circulation if one of the vessels is occluded
T
What percentage of people have a complete circle of willis
~50%
which cerebral artery is most common for ischemic strokes
middle cerebral artery
where is the most common sites of aneurysms in the brain
circle of willis occur at the bifurcations
when you are testing when you check pupillary response
focus of injury and CN III oculomotor
what is normal pupil size and reaction
2-6mm and brisk
what is the point in the medulla where the motor fibers cross
decussation of pyramids
what CN is involved in pupil reaction to light
II optic
what CN is involed in pupil restriction
III oculomotor
do SCI patients lose parasympathetic responses below their level of injury
no they lose sympathetic
what 3 bones are typically involved in basal skull #s
sphenoid, ethmoid and temporal bones
the internal carotid artery branches into what vessels
anterior communicating artery
middle cerebral artery
posterior communicating artery
The L&R vertebral arteries unite to form what
basilar artery
the basilar re-subdivides into which vessels
posterior inferior cerebellar arteries (PICAS)
what does posterior circulation supply
cerebellum occipital lobe part of the temporal lobes posterior diencephalon spinal cord and brain stem
what are the 5 components of a neuro assesment
pts story LOC CN peripheral nerves - motor strength VS
What does GCS access
LOC
what is the max score you can get for eye opening
4
spont, voice, pain, none
what is the max score for verbal
5, ox3, confused, incomprehensible words, sounds, none
what is the max score for motor
6, obeys, localizes, normal flexion, abnormal flexion, abnormal extension, none
What would you chart if there eyes were swollen shut for GCS
E1C
what is the first sign of neurological deterioration
any decrease in LOC
which CN are vulnerable to inc ICP
CN II and III - why we check them frequently
what is the term used to describe the same side
ipsilateral
what will you see regarding pupil assessment if there is increased ICP
dilated non-reactive pupil same side
what does consensual mean regarding pupil assesment
both eyes constrict
what does a patient need to be able to do to test for accomidation
follow commands
What nerves are responsible for cough and gag
CN IX glossopharyngeal and X vagus
does everyone have a gag reflex
no
if a pt is unable to cough what does this indicate
they are unable to protect their own airway
what CN are tested for corneal reflex
CN V (trigeminal) and CN VII (facial)
how do you test corneal reflex
manually open eye and touch eyelashes with corner of gauze or Kleenex - look for blinking
where does the spinal cord finish and and become the cauda equina
L@
how far do the meingeal layers continue to on the spine
S2
Does CSF circulate below spinal cord
yes
where is a common LP site
L4/L5
what are dermatones used for
to determine where injury is based on what sensory input is collected form which spinal cord level
strength changes are seen on what side from the injury
contralteral
T or F pupil changes are contralteral to injury and strength changes are ipsilateral
false
strength contralateral
pupil ipsilateral
what must you see a patient do in order to document “localizes to pain”
pt must lift hand and CROSS the midline of their body
OR rise above clavicle
if a patient does not localize to pain what do you do next
stand on the OPPOSITE side, apply nail bed presure
if a patient is trying to pull out their IV/ETT/NG what can you document for their GCS
localizing
What is cheyne-stokes breathing
cyclical episodes of apnea and hyperventilation
what is a common manifestation of intracranial injury regarding BP
systemic hypertenion
what can happen regarding autoregulation in intracranial injury? what does this result in?
loss of autoregulation
As BP increases CBF and cerebral blood volume increases causing increase in ICP
What are the 3 components of cushing’s triad
systolic HTN (wide pulse pressure) bradycardia abnormal resps (bradypnea)
what is a stroke
sudden loss of brain fn lasting longer than 24 hours
what causes a stroke (2 types of stroke)
Ischemic - interruption of blood flow to the brain
hemorrhagic - rupture of blood vessels in the brain
what are 7 stroke signs and symptoms
HA blurred vision/visual disturbances dizziness sudden confusion difficulty speaking facial droop muscle weakness, especially one sided
how do you differentiate between the two types of stroke
non-con CT
What is the penumbra
zone of ischemic tissue surrounding infarcted area
are we able to salvage the penumbra tissue
yes with treatment
What type of stroke is more common
ischemic 87%
if stroke symptoms less than 24 hours what is it termed
TIA
what are the two types of ischemic stroke
embolic (20%) - clot from elsewhere in the body
thrombotic (80%) - build up of plaque in brain
which is most common embolic or thrombotic
thrombotic
what is the most common cause of embolic stroke
afib
what are the two types of hemorrhagic stroke
intracerebral (10%)
Subarachnoid (3%)
where is a subarachnoid hemorrhagic stroke located
subarachnoid space btw arachnoid mater and pia mater
what can cause hemorrhagic stroke
trauma or structural malfomrations of blood vessels
what are two structural malformations fo blood vessels that can result in hemorrhagic stroke
aneurysms arteriovenous malformations (AVMs)
what are aneurysms
weak area of vessel bulges with blood and can burst
what are arteriovenous malfomations (AVM(
tangle of thin walled veins and arteries
congenital
what is the most common cause for rupture of AVM
uncontrolled HTN
what is the most common type of aneurysm
saccular
how long is the window of time for fibrinolytic therapy (rtPA)
<4.5 hours of onset of symptoms
what is the dosing for rtPA
0.9 mg/kg (max 90mg)
10% as a bolus, rest over an hour
what meds cant be given with tpa
no asa, heparin, warfarin or any antithrombotic or antiplatelet
what are contraindications for rtPA
head trauam/stroke < 3months AVM aneurysm recent intracranial or spinal sx active bleeding BP >185/110 siezures ICH < 6months
how often are VS done during tPA administration
q15mins x 1 hour
q 30 x 7 hrs
q8hr
how often are neuro checks done during tPA adminstration
q30 during infusion
q1hr x 8 hrs
once a pts received tPA what must their BP be kept at
<180/105
what is the pre-op/rtPA blood pressure control for stroke
<220/110 ischemic want high BP to optimize perfusion
what is the BP parameters pre-op/rtPA for SAH
SBP ~140
lower BP to control bleeding
post op/rtPA what are the difference in blood pressure monitoring for stroke vs SAH
stroke <180/105 control BP
SAH MAP >80
SBP 150-180
what are 3 things that influence cerebral oxygen supply
Cerebral perfusion pressure CPP
cerebral vascular resistance CVR
Cerebral blood flow CBF
How is CBF calculated
CPP/CVR
What is CPP
cerebral perfusion pressure
blood pressure available to perfuse the brain
what is ICP
intracranial pressure
pressure inside the head that MAP must overcome to provide cerebral perfusion
how do you calculate CPP? What is the normal range?
MAP - ICP
60-100 mmHg
What must the MAP do in terms of ICP to perfuse brain
overcome ICP
if CPP is too high what can that cause
cerebral hyperperfusion Inc ICP
if CPP is too low what can happen
brain hypoxia
what is normal ICP
0-15 mmHg
can brain hypoxia occur despite adequate CPP
yes so must consider CVR
What is CVR
amt of resistance created by cerebral vessels to blood flow
what incluences CVR
vessel diameter
ICP
what is vessel diameter influenced by in the brain
autoregulation and cereebral metabolic demand
what is autoregulation
regulatory mechanism that ensures constant CBF despite changes in arterial pressure
how does autoregulation work
changes vessel size dependent on MAP
constrict when MAP >100
dilate when MAP <60
what are the 3 conditions required for autoregulation to work
CPP >60
ICP <30
MAP 60-150
what are the two theories on how atuoregulation works
biophysical - controlled by precence of stretch receptors in blood vessels triggered by CBF
chemical
CO2 and H+ ions cause vasodiation
O2 levels PaO2 <50 causes vasodialtion
what can happen to autoregulation in TBI patients
they can lose autoregulation
CBP will increase with inc MAP and cause inc ICP
what is a common symptom in SAH
thunderclap HA worst HA of your life
what are 5 risk factors for SAH
pre-menopausal women smokers undiagnosed HTN genetics previous SAH
what grading scale is used in dx of SAH? how many grades are there?
Hunt & Hess Grading Scale
5
what are the survival percentages for each grade for SAH
1 - 70% 2 - 60% 3 - 50% 4 - 20% 5 - 10%
What grade of SAH would a patient presenting in deep coma, decerberate rigidity and moribound appearance have
5
what grade of SAH would a patient be if they precented with drowsiness, confusion and mild focal deficits be? do they have a good prognosis
grade 3
yes
what grades can go to the OR for clip or coil
2 and 3
what grade of SAH would a pt be if they had minimal or no bleed, slight HA and no neuro deficits
grade 1 - 70%
what grade SAH would a pt who is in a stupor with mild-to-severe hemiparesis and poss early decerbrate rigidity be
grade 4 -20%
what grade of SAH would a pt be if they had a mild bleed, moderate to severe HA, awake and alert, some nuchal ridigity
2 60% good prognosis
what are two types of imaing used for SAH dx
CT scan
cerebral angiography
what are 2 surgical interventions for brain aneurysms
clip or coil
What are the 3 components of the cranial vault
brain (80%)
blood (10%)
csf (10%)
what is the monroe-kellie hypothesis
ICP = cerebral blood volume + brain tissue + CSF volume
closed box
if one component increases then one or both of the other components must decrease in volume
if there is an increase in one of the 3 compnents of the cranial vault what are 6 compensation mechanisms
displacement of CSF down spinal cord to venous system
decreased CSF production (timely)
insertion of a drain to remove CSF
vasoconstriction of cerebral vasculature
surgery to remove blood clot or tumor
displacement of brain itself (herniation)
what does mannitol do? when is it used
reduces cerebral edema
osmotic diuretic pulls H2O out of the brain tissue reducing brain volume
what are 4 examples of increaesd brain volume
tumors
hematomas
abcesses
cerebral edema
What are 3 examples of things that can obstruct CSF circulation
spina bifida
tumors
pus/abcess
what can cause a block of CSF reabsorption
SAH
is it possible to cause an overproduction of CSF
yes but it is rare
what are 4 ways blood volume can be increased
vasodilation
elevated PaCO2/acidosis
loss of autoregulation
venous outflow obstruction
what are 3 ways venous outflow obstruction can occur
ETT ties
PEEP
position
How would you manage increased brain volume causing inc ICP
mannitol
how would you manage increased blood volume causing inc ICP
sedation/analgesia
HOB @ 30
reduce stimulation
how would you manage increased CSF causing inc ICP
EVD
what must you be mindful of regarding PaO2 for TBI pts
PEEP affects ICP
decide between PEEP and FiO2
What is meant by good intracranial compliance
pressure increases in the intracranial vault and there is no change in ICP
e.g. cough in healthy person or slow growing tumor
what is meant by poor intracranial compliance
small pressure is added and there is alarge change in ICP
what are 4 nursing responsibilities pre-op SAH
BP control minimize further bleeding
ensure adequate CVP and MAP - support perfusion
provide quiet environment/reduce stimulus
manage pain
Do we expect a fever to occur in SAH pts pre op? why or why not?
yes, blood irritates subarachnoid space
What must pts BP be maintained at post-op SAH
higher BP SBP 150-180
MAP >80 to maintain CPP
What medication is commonly given post op SAH? why?
statins - improve endothelial fn
increase endothelial nitric oxide synthase
helps prevent vasospasm
what is important to remember regarding ventilation in SAH patients
avoid excessive or inadequate ventilation to avoid changes in PaCO2
T or F magnesium may be given for 10 days in SAH pts post op
T
do you want to excessively sedate post op SAH pts
No, avoid it
what do you want to do with HOB for SAH pts
up to promote venous drainage
What are 3 complications of surgically treated aneurysms
seizures
hydrocephalus
vasospasm
when does vasospasm occur post surgery for SAH
3-12 days after
what is vasospasm
narrowing of lumen of cerebral arteries in response to blood clots
caused by chemical mechanism
what is the most common complication of surgically treated aneurysms
vasospasm
why do seizures occur as a complication of surgically treated aneurysms
irritation from blood in subarachnoid space causing increased ICP
why does hydrocephalus occur as a complication of surgically treated aneurysms
d/t blocking of CSF reabsorption by arachnoid vili causing increased ICP
T or F blood mixing in the CSF can impair reabsoption of CSF in the arachnoid villi causing inc ICP
T
what is the cornerstone prevention and treatment of vasospasm
Triple H therapy!
Hypervolemia
Hemodilution
Hypertension
in triple H therapy what do we do/want regarding hypervolemia
NS
CVP 8-10
increases blood flow
in triple H therapy what do we do/want regarding hemodilution
HCT 0.32 - 0.35
easier for blood flow
in triple H therapy what do we do/want regarding hypertension
levophed (30% increase in MAP)
increase MAP and CPP
What is a common drug used prophylactically for vasospasm
nimodipine
Ca2+ channel blocker
may alleviate abnormal contraction of smooth muscle and vasodilates
what must we look out for when administering nimodipine
hypotension
T or F Milrinone is a new therapeutic intervention for vasospasm
true
If there is a promeblem with increased ICP what might the doctor order
insertion of intra ventricular catheter
what do IVC’s allow us to assess
characteristics of CSF
drain excess CSF
monitor ICP when transduced
early identification of intracranial HTN
What is the purpose of having an IVC with an EVD
allow CSF drainage via external shunt
provide a method of monitoring ICP with or without an ICP transducer
what is the range for normal drainage of ventricular drains
5-15 mL/hr
if a pt drains > __ mL/hr or an increase of __ mL/hr more than usual you should notify the MD
30
10
what anatomical structure is an EVD levelled to
Foramen of Munro
where is the foramen of monro
central in brain and opening of tentorium; btw lateral and 3rd ventricle
what are external landmarks for foramen of monroe
outer corner of eye, temple, tragus
when should you flush the transducer on an EVD
NEVER
Which one of newtons law do we consider when analyzing mechanism of injury
mass x acceleration
faster the force is applied the faster the energy is released resulting in more tissue damage
4 examples of mechanisms of injury
acceleration
acceleration-deceleration
coup countercoup
rotation
What is primary vs secondary injury
primary injury happens at the accident
secondary - psysiological response to primary injury
what are 4 examples of primary injuries
concussion
contusion
fractures
blunt/penetrating trauams
what are 4 examples of secondary injuries
cerebral edema, hemorrhage, herniation, cerebral ischemia
what is index of suspicion
suspected injuries or complications based on mechanism
T or F basal skull freactures are able to be seen on CT
False need MRI
What are three symptoms of basal skull #s
rhinorrhea (CSF from nose)
Otorrhea (CSF from ear)
RAccoon eyes, battle’s sign (hematoma behind ear
T or F basak skull # pts are at increased risk of infection
true
Can you put an NG in a patient with suspected basal skull fracture
no
what is DAI how is diagnosed
diffuse axonal injury
causes stretching, tearing and shearing of nerve fibers
dx by immediate and severe decrease in LOC
widespread neurological dysfunction
what are signs and symptoms of DAI
deep prolonged coma
inc ICP, BP and temp
defict in cognition, memory, speech, motor function and personality
What are possible complications of TBI (8)
prolonged immobility - skin breakdown, DVTs prolonged invasive devices - risk for infection hypermetabolism and hypercatabolism coagulation disorders VAP, ARDS, PE delayed gastric emptying seizures fluid and electrolyte disorders
what is diabetes insipidus
decreased secretion of ADH aka vasopressin d/t damage of hypothalamus or pituaty gland
what does DI cause
polydipsia and polyuria d/t bodys inability to concentrate urine
what is CSW
cerebral salt wasting
What is SIADH
syndrome of imapprorpiate ADH
dilutional hyponatremia d/t excess of ADH secreted inot bloodstream
excessive water reabsorbed
what is the difference in urine output btwn DI, SIADH, CSW
DI increased
SIADH dec
CSW increased
serium sodium is increased or decreased in DI? SIADH?
DI increased
SIADH decreased
what is the treatment of DI
vasopressin and fluid replacement
what is the treatment for SIADH
fluid restriction
3% saline
diuretics
what is the urine osmo/serum osmo in DI SIADH and CSW
DI decrased
SIADH increased/decreased
CSW decrased
what is volume status for DI, SIADH, CSW
DI decreased
SIADH increased
CSW decrased
what head injury do you commonly see DI or SIADH
basal skull #
When does cerebral edema begin to show? when does it peak
shows 24-48 hrs
peaks at 72 hours
what are three things we can do to stop brain herniation
mannitol
craniectomy
control ICP and ensure adequate cerebral oxygenation
What is the most common type of ICP monitoring/drain device
intra-ventricular catheter
what are 5 benefits of ICP monitoring
reliable and accurate ICP measurment assess ICP with sedated/paralyzed pt determine CPP evaluate waveform to assess compliance immediate reassesment of effectiveness of intervnetions
what are the 6 questions you must ask when working with an IVC and EVD with ICP monitoring
is it leveled and zeroed to foramen of monroe? ordered to be open or closed? order for what it should be set at? safety check - secure position CSF fluctuation and characteristics good waveform?
how many peaks in one wave should you observe on an ICP wavefrom?
3
what does P1 mean
percussion wave - represents arterial pulation
what does P2 represent
Tidal wave
represents intracranial compliance
what does P3 represent
dichroitic wave
represents aortic valve closure
what does a normal ICP waveform look like
P1 highest, then P2, then P3
what would a poor compliance ICP waveform look like
P2 higher than P1 - small changes in volume can cause ICP to skyrocket - ICP rises with MAP
If you have IVC with an EVD and your ICP is 35 but your waveform doesnt look right what do you do (4)
focused neuro assesment
validate transducer placement
re-zero transducer
check for EVD fluctuation
What does hyperventilating a pt do?
removes CO2 which is a potent vasodilator causing vasoconstriction of cerebral vessels
What is a negative concequence of hyperventilating a pt
limits O2 supply ischemia & secondary injury
What are the 3 rules for hyperventilating brain injured pts
if PaCO2 is in normal range
only as a temp measure (on the way to the OR)
only if the pt is deteriorating despite interventions
Aside from hyperventilation how else can you manage cerebral O2 supply? give 6 examples
decrease cerebral metabolism thus decreasing O2 demand heavy sedation normothermia or slightly low temp HOB 30-45% quiet enviornment avoid restraints neuromuscular blockade
What are the 3 types of brain bleeds
epidural
subdural
intracerebral
cause and s&S of epidural hematomas
Skull #s and lacs to middle meningeal artery
ipsilateral dilated/fixed pupil
does an epidural hematoma require surgery
yes
is epidural hematoma from a vein or artery
artery
what causes a subdural hematoma
rupture of bridging veins in cerebral contusions and intracerebral hemorrhage
what causes an intracerebral hematoma
depressed skull #
penetrating injuries
sudden accel-decel motion
what is CBF influenced by
cerebral vascular resistance
What is PbtO2
brain tissue oxygenation monitoring
what is used to determinme PbtO2
device like pulse ox that continously monitors regional tissue oxygenation
probe inserted into area of injury and attached ot bedside monitor
what is the goal value for PbtO2
> 20 mmHg
what central line can be inserted to allow us to calculate cerebral oxygen extraction ratio
Jub Bulb Catheter
What does a jug bulb catheter allow us to calculate
cerebral oxygen extraction ratio
how does a jub bulb catheter work
central line fed into jugular vein upward into venous circulation
allows access to jugular venous blood draining from the brain only
T or F you cant do continuous reading from a jug bulb
false, can use a transducer to provide continous monitoring of the jub bulb O2 saturation
What is the normal range for SjO2
55-75%
what is CERO2? how is it calculated
cerebral oxygen extraction ratio
(SaO2-SjO2)/SaO2 x 100
what is normal range for CERO2
25-35%
if you have a low value for CERO2 what does this mean
high supply low demand
if you have a high value for CERO2 what does this mean
high demand low supply
what must occur in apnea test
CO2 must rise above 60 mmHg or at least 20mmHg higher than the start point of the test
pH must be less than 7.28
must receive 100% FiO2 applied to airway throughout the test
physician must watch for any sign of respiratory effort
T or F Brain death can be diagnosed by one physician
false
must be done by 2 physicians independently of each other
What are the 3 minimum criteria to declare brain deat
pupils fixed and non-responsive to light (> mid size)
absent brain stem reflexes
absent reflexes
What are 4 reflexes must be absent to declare brain death
bilateral corneals
gag, cough and swallow
oculo cephalic - dolls eyes
oculo vestibular - ice water
what are the 2 types of death that can allow for organ donation
neurological determination of death (NDD)
donation after cardiac death (DCD)
what type of injury is suspected in any trauma pt who has absent movement or sensation, any unconscious pt or pt with head injury
spinal cord injury
What are common causes of SCI
hyperflexion (head on collisions)
hyperextension (whiplash)
True or false parasympathetic response is lost below level of injury in SCI
false
sympathetic
What spinal cord level innervates the diaphragm
C4
injury at what spinal cord level results in tetra/quadriplegia
C1-T1
injruy at what level of the spinal cord causes paraplegia
T2-L1
what causes SCI
any mechanical force that disrupts neurologic and/or vascular supply
What is used to determine level of injury
ASIA - standard neurological classification of spinal cord injury
how are SCI categorized
by the lowest segment of the cord with normal sensory/motor function on both sides
what is primary injury in SCI
compression of cord by bone displacement
disruption of axons d/t lacerations
transaction or disruption of blood supply
what are secondary injuries in SCI
ongoing progressive damage for instability or inflammation
SIRS-like, ischemia, hypoxiea, edema
what are immediate complications of SCI
spinal shock
neurogenic shock
what is spinal shock
loss of motor, sensory, reflex and autonomic fn below level of injury
flassic paralysis
loss of bowel/bladder fn, temp control
sudden cessation of impulses from the higher brain centers
when does spinal shock occur
immediately or w/in several hours of injury
what type of shock is neurogenic shock
distributive
what can occur with severe cervical and upper thoracic injuries
neurogenic shock
What happens with neurogenic shock
loss of sympathetic input to the systemic vasculature of the heart and subsequent decreased peripheral vascular resistnace
what are the parasympathetic signs of nuerogenic shock
hypotension
severe bradycardia
loss of ability to sweat below the level of injuries - warm, dry extremeites)
what are the 6 SCI best practice guidelines
cervical immobilization
spinal xray series and CT/MRI in first 48 hours
MAP maintained 85-90 mmHg for first 7 days
DVT prophylaxis - anticoagulants and SCDs
