Exam 1: A&P, hemodynamics, fluids, anesthesia agents Flashcards
what part of the neuron contains the nucleus
cell body
what part of the neuron receives signals
dendrites located on cell body
what part of the neuron carries the action potential from the cell body to the axon terminals
axon
what part of the neuron transmits signals to other cells
axon terminal
what part of the neuron covers the axon and speed transmission
myelin sheath (made of fat)
what part of the neuron makes the myelin
schwann cells
what is the space between schwann cells where electrical messages jump
Nodes of Ranvier
nueron cell body in the CNS is made of _________ matter
grey
myelinated axons are ________ matter
white
what are the types of neuronal cells
motor, sensory, interneurons
motor nerves are _________polar
multi
sensory nerves are _______________polar
pseudomonipolar
internuerons are ___________polar
pseudomonipolar
what are the 4 types of neuroglial cells
astrocytes
oligodendrocytes
microglial
ependymal
what do neuroglial cells lack
dendrites, axonal processes
what neuro cell is essential for BBB, structural support, injury repair, are what most neoplasma aris from, have pair neurons and nerve terminals
atrocytes
what neuro cell forms myelin sheath of axon in brain (regeneration)
oligodendrocyte
what neuro cell is th smallest cell, acts like a macrophage for debris, and is transported to sites of neuro injury
microglial
what parts of brain lack a BBB
postrema
pituitary gland
pineal gland
choroid plexus
portions of hypothalmus
what neuro cell lines the roof of the 3rd and 4th ventricles and central spinial canal, they form the choroid plexus
ependymal
what is the thickest and most outer layer of the spinal cord
dura mater
what seperates the cerebral hemispheres
falx cerebri
what seperates the occipital and cerebellum
tentorium cerebelli
what layer of the spinal cord is avascular and is joined to the dura mater
arachnoid mater
what layer of the spinal cord is adhered to the brain and spinal cord
pia mater
what is the space between pia and arachnoid mater filled with CSF
subarachnoid space
how far down does the subarachnoid space extend to
s2-s3
what space surrounds the dura in spinal canal, contains venous plexus
epidural space
what are some safety mechanisms in the brain
BBB
CSF
what is function of BBB
isolates brain to maintain homeostasis, tight barrier for water soluble molecules
what is the volume of CSF
150 ccs
what is function of CSF
cushions the brain provides an extracellular milieu for neurons and glial cells
what lobe of brain is for judgement, foresight, voluntary movement and smell
frontal
what lobe of brain is for intellect, emotion, and hearing
temporal
what area of the temporal lobe controls speech
Brocas
what area of temporal lobe conrols speech comprehension
Wernickes
what lobe of the brain controls visual stimuli
occipital lobe
what part of the brain controls swallowing, breathing, and heartbeat
brainstem
what part of the brain controls movement
the motor cortex of the frontal lobe, forward of the central sulcus
what part of the brain controls pain sensation
sensory cortex, posterior of central sulcus
what part of the brain controls coordination
cerebellum
what lobe of the brain controls comprehension of language
parietal lobe
what part of brain is the master neurohumerol organ and regulates body function
hypothalmus
what part of brain regulates emotion/pain response, appetite and stress response
amygdala
what part of brain does movement and reward
basal ganglia
what part of brain is the sensory gateway
thalamus
what part of brain regulates memmory
hippocampus
list spinal/epidural layers
Skin,
sub q tissue,
supraspinous ligament,
interspinous ligament,
ligamentum flavum,
epidural space,
dura mater,
arachnoid mater,
sub arachnoid space,
pia mater,
spinal cord
where is CSF made
choroid plexus of lateral third and fourth ventricles in subarachnoid space
in ependymal cells lining the ventricles
what is total volume of CSF
150 mls
what is rate of CSF production
30ccs/hr
what is pressure of CSF
5-15 mmHg
where is CSF absorbed
arachnoid villi into the venous system
what is Specific Gravity of CSF
1.002-1.009
what is the pH of CSF
7.32
what are the components of CSF
K, Ca, HCO3, Glucose (<plasma)
Na, Cl, Mg (>plasma)
what is the flow of CSF
Lateral ventricles -
interventricular foramen (foramen of Monro)
third ventricle
cerebral aqueduct
fourth ventricle
lateral apertures and median aperture
subarachnoid space-
arachnoid villi
superior sagittal sinus
how often is CSF volume replaced
every 3-4 hours
what kind of nerves originate on the dorsal spinal cord
sensory/afferent
what kind of nerves originate on the ventral spinal cord
motor/efferent
describe pathway of stimulus to response
peripheral receptor receives stimuli
sensory neruon (afferent) carries mease to CNS
interneuron
motor neuron (efferent) message from CNS to body
effector- muscle or gland carries out response
what arteries feed the circle of willis
internal carotid (anterior)
vertebral arteris (posterior)
what arteries branch off of the circle of willis
anterior, middle, and posterior arteris
what is cranial nerve 1
olfactory (smell)
what is cranial nerve 2
Optic - vision
what is cranial nerve 3
Oculomotor.
Functions in raising the eyelid, directing the eyeball, constricting the iris, and controlling lens shape.
adduction of the eye medial
what is cranial nerve 4
Trochlear. Primarily a motor nerve that directs the eyeball. (superior oblique)
what is cranial nerve 5
Trigeminal. Three divisions: Opthalmic (V1), Maxillary (V2), and Mandibular (V3).
mastication, sensory from face
what is cranial nerve 6
Abducens- abduction of the eye (lateral)
what is cranial nerve 7
Facial- muscle of face, taste (anterior 2/3 tongue)
what is cranial nerve 8
Vestibulocochlear/acoustic
balance-vestibular
audition- cochlear
what is cranial nerve 9
Glossopharyngeal taste (posterior 1/3 tongue) carotid body and sinus efferent
what is cranial nerve 10
Vagus, heart, motor control fo larynx and pharynx
what is cranial nerve 11
accessory, shoulder and head movement
what is cranial nerve 12
Hypoglossal moves tongue
which cranial nerves are sensory
1
2
8
what cranial nerves are motor
3
4
6
11
12
what cranial nerves are mixed
5
7
9
10
how do alzheimers drugs like rivastigmine (exelon) work
acetylcholinesterase inhibitor
blocks breakdown of acetylcholine to increase levels in brain and provide better transmission
what kind of neurotransmitter/receptor do interneurons use
ACH and nicotinic receptor
what kind of neurotransmitter/receptor do parasympathetics use
ACH and muscarinic at target organ
what kind of neurotransmitter/receptor do sympathetics use
NE or ACH and muscarinic receptor
what kind of neurotransmitter/receptor does somatic system use
ACH and nicotinic
what percent of total body oxygen does brain use
20%
the brain uses 60% of O2 to make __________ and support electrical activity
ATP
what is CMRO2 in adults
3-3.8 ml/100g/min or 50 ml/min
the brain reaches unconsciousness after ______________ of interrupted blood flow
10 seconds
after __________________ of no blood flow the brain has cellular injury
3-8 min
what is volatile effect on brain (CMR, CBF, ICP)
decrease CMR
increase CBF
increase ICP
what is the best volatile for neuro and why
ISO
increases CSF absorption
What is CPP and how is it calculated
cerebral perfusion pressure
CPP = MAP - ICP
what is normal CPP
80-100 mmHg
what happens with CPP <50
slowed EEG
what happens with CPP <25
irreversible brain damage
what range of MAP is CBF stable
60-160 mmHg
CBF directly mirrors ___________
PaCO2
how does a lower hct effect blood flow
improved
how does a high hct effect blood flow
decreased BF
what does hypoglycemia do to brain
injures
what does hyperglycemia do to brain
exacerbates global and focal hypoxic brain injury by accelerating cerebral acidosis and cellular injury
what rate does brain consume glucose
5mg/100g/min
MAP calculation
(SBP+ 2x DBP )/3
what does a decrease in CPP lead to
cerebral vasodilation
what does an increase in CPP lead to
cerebral vasoconstriction
what is the result of crazy HTN
disruption in BBB, brain swelling and bleeding
what is result of hyperventilation on brain
CO2 decreases, vessels vasoconstrict, decreased blood flow, inverse steal causing ischemia
what ICP level leads to brain herniation
> 30 mmHg
what are s/s increased ICP
HA, vomiting, papilledema, vision changes, change in mentation/somnolence, GCS reduction
what is physiology of increased ICP
-Displacement of CSF from cranium to the spinal canal
-Increase in CSF absorption
-Decrease in CSF production
-Decrease in total cerebral blood volume
what is optimum HCT for neuro patients
30-34% for optimal carrying capacity
what is optimum PaO2 and SpO2 for neuro patients
normal
what is optimum CO2 for neuro patients
normal (35-45) or higher
GCS
EYE
4- spontaneous
3 sound
2 pressure
1 none
Verbal
5 oriented
4 confused
3 words
2 sounds
1 none
MOTOR
6 commands
5 localizes
4 normal flexion
3 abnormal flexion
2 extension
1 none
what is GCS score 13-15
mild
what is GCS score of 9-12
moderate
what is GCS score of 3-8
severe
what does the BP tell us in the brain…
no idea but maintain or slightly increase BP during anesthesia
what happens to CBF when PaO2 is 50mmHg or less
increases CBF
CBF changes ________________ per mmHg change in CO2
1-2 ml/100g/min
CBF changes __________ per every 1* change in celsius
5-7%
what is cushings triad
HTN, bradycardia, irregular breathing
what does cushing triad tell us
herniation/increased ICP
what kind of fluids do we avoid in intracranial HTN
glucose containing fluids
where do you zero a line for intracranial HTN
circle of willis
what paralyzer do we avoid in intracranial HTN
succs
what safety device do we have ready for intracranial HTN
suction for vomiting
what kind of emergence do we want for intracranial HTN
smooth
what do we elevate HOB at for intracranial HTN
HOB >30*
what anesthetic agents increase Cerebral vascular resistance
thiopental, propofol, etomidate
T/F keep neuro patients hypothermic
true
T/F use PEEP in neuro patients
false
what anesthetic agents do NOT reduce electrical activity
nitrous
ketamine
what is the effect of N2O on brain
increases CMR, CBF, and ICP, can cause bubbles in brain
what is effect of lidocaine on brain
decreases CMR, CBF, ICP, is neuroprotective
what patients do we avoid lidocaine in
seizure patients
T/F use flumazanil/romazicon in neuropatients
be cautious, lowers neuroprotection
T/F use naloxone/narcan in neuro patients
be cautious, lowers neuroprotection
what is the effect of most vasodilators on brain
cerebral vasodilation and increases CBF
what effect does SUCCS have on brain
increases ICP
what monitors brain waves
EEG
what type of patients have EEG monitors
stroke
what is frequency on EEG
time between impulses
what is amplitude on EEG
peak to peak measurements on verticle plane, measured in microvolts
what are the worst 3 waves on EEG getting worse
Delta waves
burst suppression
isoelectricity
what is an early warning sign on EEG of declining neuro health
delta waves
what can a bolus of anesthetic drugs lead to
burst suppression- communicate to team before you bolus
what waves are on normal EEG
Beta and alpha waves
what happens with early onset of ischemia/hypoxia on EEG
theta and delta waves
what happens with increased hypoxia on EEG
delta waves
what happens on EEG with worsened hypoxia
burst suppression
what kind of waves happen with closed eyes and deep relaxation
alpha waves
what kind of waves happen with normal awake consciousness
beta waves
what kind of waves happen with light sleep
theta
what kind of waves happen with deep sleep
Delta waves
what do you communicate to OR team before induction
bolusing drugs, may see delta waves
how does epilepsy appear on EEG
high voltage spikes with slow waves
how does ischemia appear on EEG
slowing frequency with preserved amplitude
how do anesthetic agents appear on EEG
similar to global ischemia or hypoxemia (slowing frequency with preserved amplitude)
what MAC of des and sevo leads to burst suppression
1.2
what MAC of iso leads to bust suppression
1.5
how does low dose volatile effect EEG
increases Beta waves, some alpha waves
how does moderate dose volatile effect EEG
only beta waves
how does high dose volatiles effect EEG
delta. and theta waves
what two IV anesthetics lead to burst suppression
propofol and etomidate
how does large dose of opioids effect EEG
slow delta waves
T/F muscle relaxants effect EEG
false
what is technology behind cerebral oximeter
neat infared spectoscopy measures light absorbance to calculate oxy-hemoglobin deoxyhemoglobin
indirectly measures brain activity
what does cerebral oximeter detect/monitor
decrease in CBF in relation to CMRO2
what kind of blood does cerebral oximeter measure
venous
how do you set up cerebral oximeter
- alcohol prep
- pad on either side of head
- mark baseline
- start O2
what change do we watch for in cerebral oximeter or that causes alarm
20% change
what procedures do we do SSEPs for?
usually spinal cord
what is a 50% decrease in amplitude or a 10% increase in latency indicative of for SSEPs
possible ischemia (decreased blood flow to spinal cord )
what is effect of volatiles and barbiturates on SSEPs
increase latency and decreased amplitude
what is anesthetic plan for enoke potentials
TIVA, dont use NDMB
propofol and remi good option
precedex good option
can use anectine for intubation
when do we notify surgeon about Evoke potential numbers
50% decrease in amplitude or 10% increase in latency
what do evoke potentials help us detect
ischemia to spinal cord or cerebral cortex
what are examples of neuroprotective drugs (decrease CMRO2)
propofol
what are epileptogenic drugs to avoid
lidocaine
phenergan
robaxin
demerol
what are drugs that increase ICP
anectine increases by 5 mmHg
ketamine
what drugs cross the BBB (limit use of these
Benadryl
scopolamine
atropine (use robinol instead)
what drugs do we avoid that cloud sensorium
benzos
what drugs depress immune protective mechanisms
N2O, etomidate
what drugs increase cerebral steal?
nitroprusside and nitroglycerin, so use nicardipine instead
what drugs do we utilize that decrease the risk of intracerebral arterial vasospasms
nicardipine
magnesium sulfate
why do avoid narcotics in brain cases
brain has no pain receptors
what medications do we use to treat autonomic responses in neuro cases
propofol
esmolol
what part of head has pain receoptors
skin
when do we give opioids in neurocases
with emergence/closure of head
what medications can we give to decrease ICP
hypertonic Na
mannitol
lasix
what do we monitor with mannitol and lasix
electrolytes
UOP
BP
what is goal of fluid management of neuropatient
minimize neuronal injury
maintain organ perfusion
T/F inhalational anesthetics effect brain more than IV drugs
true
T/F N2O and ketamine decrease CMR
false
what is brain protective MAP
60-160
how can we manipulate CO2 to increase cerebral blood flow
hypoventilate to increase CO2 and vasodilate
how can we manipulate CO2 to decrease blood flow and ICP after giving ketamine
ketamine increases ICP
hyperventialte to decrease CO2
vasoconstrction
decrease ICP
what are effects of ISO, DES and SEVO on
CMR
CBF
ICP
decrease CMR
increase CBF
increase ICP
what is effect of barbiturates, etomidate, propofol, benzoson
CMR
CBF
ICP
decreased CMR
decreased CBF
decreased ICP
what is effect of ketamine on
CBF
ICP
increase CBF
increase ICP
what is the best volatile for Neuro
iso
what inhaled anesthetic do we avoid for neuro
N2O
what is the most common reason to have high ICP with succs
light anesthesia
what do we want ICP to be at before we open dura
lower
what can happen if ICP is high when dura is opened
herniation
what diuretics do we give to lower ICP
mannitol 0.25-1 g/kg followed by furosemide for up to 6 hrs
what is goal of BP during neuro case
normovolemia
MAP within 20%
what is goal serum osmolarity for neuro
305-320
what can cross the BBB
water, O2, glucose
what cannot cross the BBB
Na, Albumin, HCO3
what can happen with severe fluid restriction
hypovolemia
hypotension
decreased CBF
ischemia to brain and organs
moderate decrease in brain H2O
decreased tissue perfusion and oxygenation
decreased serum pH (hyperventilate to prevent acidosis)
monitor UOP, HR, BP
what can excessive hypervolemia lead to
HTN
cerebral edema
when do we want patient to be in a dehydrated/hypovolemic state
space occupying legions
CSF drainage/production problem
cerebral swelling with increased ICP
cerebral aneurism
how do we manage patient in a hypovolemic state
fluids on a microdrip, turn fluids off immediately after induction drugs
why dont we fully replace fluid in neuro cases
save space for blood replacement at end of case
what do we monitor for fluid balance
UOP
HR
BP
electrolytes
when do we want hypervolemia in neuro
cerebral aneurism repair
prevent vasospasm
when do we give patient fluids to make a hypervolemic state to prevent vasospasm
before dura is open be fluid sparing to keep ICP down, same during procedure
after aneurism is clipped ask surgeon if we can increase fluid to avoid vasospasm
what are the three Hs for cerebral aneurism repari/vasospasm prevention
hypervolemia
hypertension
hemodilution
what types of patients do we use hypertonic saline on
mass effects, midline shifts, high risk for post op cerebral edema, recipients of osmotic diuretics
what are hyponatremic patients at risk of
brain herniation
what are doses of hypertonic saline
50 ml/hr of 3%
30 ml/hr of 7.5%
at what sodium level do we give hypertonic saline
<135
at what sodium level do we hold hypertonic saline
> 150
T/F replace fluid deficit in neuropatient
False
what fluid do we use for management in neuro patient
NS (isotonic)
what do we replace UOP with in neuropatient
NS
what are potential areas of hidden blood loss in crani
blood loss in drapes and head bag, lots of irrigation, mannitol and lasix losing more fluids so monitor fluids and electrolytes when using these drugs
what is best way to monitor blood loss in nuero patient
get baseline hct and recheck
what is average blood loss of crani
1L
HCT drops ______ for every 100 ccs of blood loss
1
how much blood does a raytec hold
10-20 ccs
how much blood does a lp hold
50-100 ccs
what is risk of replacing fluid loss with NS
hyperchloremic metabolic acidosis
what do we watch closely with manntol and lasix
fluids and electrolytes
what do we want BS to be
150 and under
what is normal blood flow in brain
50 ml/100g/min
what blood flow is associated with failure and structural damage
less than 20-25 ml/100g/min
when is dehydration needed in neuro
-space occupying lesions
-csf drainage/production problem
-cerebral swelling w/increased icp
-cerebral aneurysms
-when there is need to save space for blood product admin
-post op swelling anticipated
what labs should be monitored hourly for acid base status
base deficit
pH
HCO3
what should be monitor continously for fluid balance
UOP
HR
BP
how do we manage fluid for heads
npo defecit not replaced, caution fluid because of increased icp with dural opening
how do we manage fluids for spines
give a little fluid preop, then give albumin in or, and then gauge replacement based on uop, blood loss, bp, hr, etc.
what is positioning consideration for spines
prone so fluid goes to eyes, be conservative
what drugs do we avoid in neuro
lido
phenergan
robaxin
demerol
succs
ketamine
benadryl
scopolamine
atropine
benzos
N2O(crani)
etomidate
nitroprusside
nitroglycerin
what is latency on SSEP
time for evoke response to be measured in brain
what is effect of most anesthetic drugs on SSEPs
decrease amplitude, increase latency
what neuron function is motor
multipolar
innervate/control effector muscles and glands
what neuron function is sensory
psuedomonipolar
receive exteroceptive, interoceptive, and proprioceptive input
what neuron function is interneurons
pseudounipolar
connect to an adjacent neurons
what is grey matter
neuron cell bodies in the CNS
what is white matter
myelinated axons
