Test 1 Travis Flashcards
Adding this to LA for retrobulbar block may enhance spread.
This substance is a hydrolyser of connective tissue
Hyaluronidase
successful block of retrobulbar block will be marked by these three effects
anesthesia
akinesia
blockade of oculocephalic reflex
(this is the dolls eye reflex - when blocked your eyes will not continue staying midline/focused on one object when blocked so ur eyes will move with ur head turn in sync)
blockade of retroperitoneal block should not be performed in what 3 diseases
- bleeding disorder
- extreme myopia (produces elongate globe of eye - high risk for globe perforation
- open eye injuries (inc pressure behind eye - risk for extrusion of eye contact with LA inj)
blocking this nerve prevents squinting of eye
facial
three techniques of facial nerve block
van Lint
atkinson
O’brien
major complication of facial nerve block
SQ hemorrhage
name 3 peribulbar block sites
inferotemporal
superonasal
medial
in this ocular block you have profound analgesia but movement may still be present
sub-tenon block
tenon tissue fuses anteriorly with what structure
conjunctiva
tenon tissue encapsulates this structure posteriorly
globe
oculocariac reflex involves afferent ___ ____ nerve and efferent ____ ____ nerve.
afferent sensory trigeminal
efferent motor vagus nerve
these fibers have a short chronaxy bc of relatively low capacitance of their myelinated membrane
motor fibers
these fibers have a long chronaxy because of their higher capacitance of their non myelinated membranes
C Pain fibers
Short/Long duration is the best discriminator of distance btw needle and nerve
shorter
____ MHz best for shallow structures
____ MHz best for deeper
10-13 shallow
2-5 deep
US structures appearing
Black - high water content (vessels, local csf) are__
White - transmission blocked, bone, air are ___
Gray - intermediate density - organs
anechoic - ie big black vein on US
hyperechoic - ie whitest muscle nerve, bone
hypoechoic - organ
exhibiting this.. implies that the received echo varies up angle of insonation
anisotropy
transducer angle changes in image of US
best visualization of needle tip is when the bevel is oriented which way
directly toward or away from the transducer
why deep 90 degree insertions do not show up well i suppose?
this segment of the spinal cord provides for ventral rami of brachial plexus
C4 - T1
cervical enlargment
this segment of the spinal cord provides for lumbar and sacral plexus
L2 - L3
lumbar enlargment
CSF is produced by ___ ____ of cerebral ventricles
choroid plexus
CSF is reabsorbed by ____ _____ along the sagital sinus
arachnoid granulation
SAS space contains this much CSF
25 - 35 ml
some texts up to 80
total body CSF
100 - 150 ml
what is specific gravity?
density of substance compared to density of water
what is baricity?
SG LA : SG CSF
Specific gravity directly depends on these two things
protein in CSF
gravity
changes in specific gravity is related to presence of this substance (CSF)
bilirubin
relationship of temperture to SG
every 1 degree of inc temp = dec SG x 0.001
anterior 2/3 supply to cord
ASA (single)
anterior lower 1/3 supply to cord
Artery of Adamkiewics
Artery of Adamkiewics is also know as
arteria redicularis magna (ARM)
injury to Artery of Adamkiewics may cause this syndrome which is a spinal cord infarct
Anterior spiral artery syndrome
Artery of Adamkiewics is in what segments of spine
T9 - L1
posterior 1/3 supply to cord
PSA (pair)
all arterial branch from this artery
vertebral
anastomosis btw spinal arteries
arterial vasocorona
epidural widest space in spine
L2 (5 - 6 mm)
epidural narrowest space in spine
C5 (1.5 - 2 mm)
when supine these are the two lowest points in spine
T6 S2
when supine these are two highest points
C3 L3
this spinal abnormality results from attempt to restore center of gravity
lordosis
bony knob at base of neck on spine segment
C7 (most prominent)
lower limit of scapula on spine segment
T7 - 8
terminal point of 12th ribs on spine segment
L2
posterior iliac spines on spine segment
S2
sacral hiatus and sacrococygeal ligament on spine segment
S5
conus medularis adult
L1
dural sac ends
S2 (correlates with posterior iliac spine)
tufier or line across iliac crest
L4
dermatomes: clavicles
C5
dermatomes: lateral parts of upper limbs
C5, 6, 7
dermatomes: medial sides of upper limbs
C8, T1
dermatomes: thumb
C6
dermatomes: hand
C6-8
dermatomes: ring and little finger (pinky)
C8
dermatomes: level of nipples
T4
dermatomes: umbilicus
T10
dermatomes: inguinal or groin region
T12
dermatomes: anterior and inner surface of lower limbs
L1, 2, 3, 4
dermatomes: foot
L4, 5, S1
dermatomes: medial side of great toe
L4
dermatomes: posterior and outer surface of lower
S1, S2, L5
dermatomes: lateral margin of foot and little toe
S1
dermatomes: Perineum
S2, 3, 4
dermatomes: genital
S2, 3
dermatomes: anal spincter area
S5
sensory blockade interrupts both ___ and ___ stimuli
somatic
visceral
motor blockade produces relaxation of what
skeletal muscle
differential block seen more in ____ spinal segments
rostral
assessing blockade: nerve stimulation of this mA, Hz, and duration is considered equivalent to surgical stimulation
60 mA
50 Hz
5 sec
most sensitive indication of initial onset of sensory block (assessment type)
alcohol swab and similar tests
most accurate assessment of overall sensory block
pinprick or blunt needle
vasomotor tone is primarily determined by what sympathetic fibers
T5 - L1
causes vasodilation of venous capacitance
pooling
dec SVR
cardiac chemoreceptors in LV wall get stimulated causing this reflex
Bezold - Jarisch
primary action of sympathetic blockade is due to this.
venodilation
apnea is almost always due to ____ of the respiratory centers in medulla.
hypoperfusion
-due to severe hypotension
Mortality of general anesthesia is __% higher than neuraxial
16.7%
advantage of neuraxial: can assess TURP patients during surgery for patient to alert physician of __ __.
Bladder distension
TURP syndrome s/s
hypervolemia
hyponatremia
ammonia toxicity
8 things. absolute CI/going to hell if you administer neuraxial with these conditions/disease/situation
infection at site refusal major coagulopathy severe hypovolemia/blood loss severe aortic or mitral stenosis or severe IHSS increased ICP procedure last longer than duration of block abruptio placentae
what about coumadin
dc at least 4 days prior
can do or remove if INR <1.5
NSAIDS or ASA with neuraxial?
can receive regardless of last dose
SQ heparin
not CI
do block > 1h before heparin and
remove 1 h prior to dose or 4h after dose
LMWH
hold 12 hours prior to block
restart 24h post after surgery
remove at least 2h prior to restarting lovenox or 10h after dosing
Hold ticlopidine for
14 days
hold clopidogrel and parasugrel for
7 days
hold abciximab for
2 days
hold eptifibatide for
8 hours
3 herbs to caution with bleeding
garlic - 7 days
ginko - 26 h
ginsen - 36h
*return time to normal hemostasis
no indication to DC prior to neuraxial
this type of needle associated with less PDPH, no cauda equina puncuture and stays more midline
noncutting
give two names for the anatomical location of L4
tuffier’s line
aka intercristal line
(btw iliac crests)
this condition is betadine enters SAS
chemical arachnoiditis
neurtalizes iodine
alcohol
skin to dura depth in all three patient types
thin
typical
obese
2.5 cm
5 cm
9 cm
needle smaller than this gauge needs introduces (spinal)
25 g
these landmarks are avoided with paramedian approach
supraspinous lig
interspinous lig
this largest interspace is used during the taylor approach
L5
adding these to LA makes hypobaric
sterile H20
opioids (except demerol) - think “getting high”
makes LA isobaric
mix with CSF
mix with NS
most important factors determining level of blockade
baricity
positioning
LA dose
DOA from shortest to longest
lidocaine < rop < bup/levobup < tetra
epi/neo best prolongs LA in this order from best to worst
tetra < lido < bup
clonidine produces dose dep analgesia w/o side effects by activating ___ alpha __ receptors in the ____ ____.
post synaptic alpha 2
substantia gelatinosa
repeating a dose of lidocaine following a “failed” spinal may cause this (so dont do it)
cauda equina syndrome
characteristics of cauda equina syndrome
bowel and bladder dysfx
paralysis of legs
sensory deficits
pain from multiple nerve root injuries
5% lidocaine can be neurotoxic
this agent can increase duration of spinal and can be the solo injected spinal
opioids
describe how opioids when injected into spine
passive diffusion into dorsal horn
bind to opioid receptors
block substance P release
pain from gluteal region radiating to BLE ..sx start within a few hrs to 24h post recovery (can have redicular back pain) may need opioids to tx…spontaneously disappear within 10 days
Transiet Neurologic symptoms
the extent of epidural spread is is determined by these two most important factors
dose
site of inj (ie ED space cervical
volume most effects ___ and concentration mostly affects ____
spread
density
successful analgesia can be obtained with relatively ___ volumes and ___ concentrations
low volumes
high concentrations
where would your epidural catheter desination be in these procedures: labor epidural abd surgery thoracic chronic pain
labor L2 - L3
abd T8 - T10
thoracic T4 - T5
c. pain C7 - T1
injecting into ED space too fast may cause these 3 things
inc CSF pressure
h/a
inc ICP
(epidural) segmental spread may be (3-4x) higher in these two types of patients. May need to use lower volume (0.5ml/segment)
elderly
OB
(slide on neuraxial opioids) two factors influencing diffusion
lipid solubility
molecular weight
late depression of ventilation occurs with this drug (neuraxial)
morphine
early depression of ventilation occurs with this drug (neuraxial)
fentanyl
the concentration of opioid is selected to acheive an infusion rate of ___ ml/hr. Lower infusion rates may not deliver adequate analgesia, while higher rates will be associated with motor block and inability to ambulate. (PP slide on dosing regimens for neuraxial opioids - in italics on bottom)
6 - 10 ml /hr
sacral anatomy changes around this age which makes identifying
12 yo
major complications of caudal includes
unintentional needle trauma to epidural venous plexus in sacral region and dural puncture (more likely in infant)
most frequent neuraxial complication that is usually mild and self limiting
back pain - from muscle strain/relaxation
intravascular inj more significant with doses given in these two spaces
epidural
cuadal
(both receive high volumes)
injected into this area with epidural dose will have effects similar to high spinal. onset 15-30 min. tx like high spinal
subdural inj - spreads to the very thin arachnoid quicker than interdural
this neuraxial side effect may cause compression of neural tissue and cause injury and ischemia with what resulting symptoms 3 symptoms, and tx
--spinal or epidural hematoma 1 back pain 2 motor weakness 3 sphincter dysfunction ---immediate MRI/ or CT surgical decompression within 12 hrs
this neuraxial side effect occurs in four stages.. and what are they
abscess
- back pain
- nerve root/redicular pain
- motor/sensory deficit
- paralysis
causes of abscess. list most common and others
most common Staph Aureus
alpha hemolytic streptococci
psoriasis - poor skin prep
DM, sterroids, chronic infections (HIV, herpes)
back pain plus fever .. do what
remove cath and culture tip
location and characteristics of PDPH
bilateral, frontal, retroorbital, occipital and extends to neck. throbbing or constant with photophobia and nausea (cerebrovasodilation, dec CSF pressure)
with PDPH you have loss of hydrolic support where medulla and brainstem are dropped into foramen magnum this stretches the ____ and pulls down on the _____.
meninges
tentorum
this tx stimulates production of CSF
hydration
caffiene
supine position increases? or decreases? hydrostatic pressure - which drives fluid out of the ____
decreases
dura
whats in fioricet
benzo + tylenol + caffeine
do this upper airway block for PDPH- emerging technique
sphenopalatine ganglionic
oculocardiac reflex most likely in this procedure/population
children
strabismus
local infiltration into this muscle for oculocardiac reflex, after stopping stimuli and giving anticholinergics
rectus muscle
during retrobulbar block we inject into this structure
extraocular muscle cone
clinical signs of brainstem anesthesia after opthalmic anesthetic
alt concsciousness proceeding to apnea, cardiac instability, dilation of contralateral pupil
(manifests within 6-10 min) Seizures are NOT a typical feature
differential excessive opioids from brainstem anesthesia from opthalmic block
opioids- miosis
brainstem anesth - mydriatic and nonreactive pupil with akinesia of that globe
this is the degree of difficulty demonstrated by a sound wave being transmitted thru a medium; density (p) x acoustic velocity (c); z = pc.
acoustic impedence
-increases if propogation speed or denstity of medium increased
how does frequency change US image
US gradually absorbed by tissue
higher frequency = more rapid absorption and less distance propogation. Ergo- use low freq for deeper scan
5 US transducer manipulation techniques
depth frequency focusing gain doppler
correlation btw nerve diameter and conduction velocity
larger diameter = faster conduction
smaller = slower
major site of LA effect
“h” gate of alpha subunit in the Na channel
LA binds in Na channel in these two states
inactivated
open
(this is frequency blcokade)
myelin axons rely on ____ _____ for impulse propogation, at least __ consequtive Nodes of Ranvier must be blocked to prevent transmission down axon
saltatory conduction
2
tachyphylaxis to LA is more likely if…
blocking agent is NOT reinjected soon after the first signs of returning sensation. be sure to reinject frequently with first signs of returning sensations.
segments of the spine for larynx
c3 (epiglottis) - C6 (cricoid)
transverse arytenoids do this
closes rima glottis
hypoglossal cranial nerve
12
RLN and SLN sensory division locations
SLN above cords (to epiglottis)
RLN below cords
anesthesia to nasal septum and nasopharynx blocks these 3 nerves
anterior ethmoidal
nasopalatine
sphenopalatine
(origin - opthalmic and maxillary divisions of trigeminal)
benzocaine or cetacaine spray provides anesthesia to ___ portion of tongue and mouth by blockade of ____ and ____ nerves
anterior
trigeminal and glossopharyngeal
treatment for methylhemaglobinemia
1-2 mg/kg 1% Methylene Blue - slow IV push over 5-10 min (vargo)
when doing a glossopharyngeal block - if you have tachycardia it is bc of blockade of what nerve fiber
afferent of glossopharyngeal arising from carotid sinus
contraindication for transtracheal block
increased ICP
open globe injury
.. also goiter or tumor
monitor patients for at least this duration for s/s of LAST
30 min (due to biphasic pattern)
rare complication to US gel related to preserves is called ___ ___. These 3 substances.
contact dermatitis 1. propylene glycol 2. parabens 3. imidazolidinyl urea (PPI)
neuropathy prognosis from PNB neuro damage
95 % resolved in 4-6 wks
99 % resolved in 1 year
how to confirm nonstimulating cath position
bolus saline thru catheter - spread on US
to widen space to threat catheter inj this
d5w (not saline)
pulse width =
duration
this current = intraneural needle placement
< 0.3
PNS + central neuraxial block.. okay or not?
yes
these nerve fibers have long chronaxy
C fibers
bc entire axon counts and needs longer duration of stimulus
pulses used at duration of ____ are most effective over all (rheobase or chronaxy)
chronaxy
advance needle until this mA and duration reached
- 3 - 0.5 mA
0. 1 ms
shallow structures < 4 cm use ___ MHz
Deeper __
shallow 10-13
deep 2-5
most common cause of artifact
contact artifact from loss of acoustic coupling btw transducer and skin
topical anesthesia not appropriate for which eye surgery
posterior chamber
ocular blocks (most common and effective for akinesia and profoudn analgesia) anesthetize these cranial nerves
III oculomotor IV trochlear V trigeminal VI abducens VII facial
optic nerve is a continuation of the brain and the dura mater divides at the enterance of …
optic nerve into the orbit
blockade of optic nerve occurs in the
optical epidural space
in retrobulbar block, LA injected where
behind eye into cone formed by extraocular muscles
needle advanced 3.5 cm toward apex of cone
this resp syndrome probably due to inj of LA into optic nerve sheath with spread to CSF.. and Tx of this
PRBA
- post-retrobulbar block apnea - apnea in 20 min, resolves within hour
- supportive and positive pressure ventilation
what gives the spine its flexibility
cartilaginous disks
movable joint surfaces (24 of 33 vertabrae)
provides passageway for spinal nerves to exit
intervertebral foramen
rudimentary articulate process on sacrum and coccyx which is more prominent in children and is an important landmark for caudal anesthesia (“horns”)
cornu
this ligament in spine is typically absent/poor in cervical region, thin membrarous lig, thickest in lumbar
Interspinous lig
meningies protect the cord from forament magnum to ___ ___ ___
cauda equina base
cause inc SG of CSF
adv age
glucose
protein
uremia
for pts with pulm disease, dermatomes needed above this location should alert providers to weigh benefits/risks due to high risk
above umbilicus
