Neuraxial Anesthesia Flashcards by Elisabeth Tribeck

what are the different names for a spinal

subarachnoid
intrathecal

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How many of each kind of vertebrae are there?

7 cervical
12 thoracic
5 lumbar
5 sacral
4 coccygeal

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what structure is different on the 7th cervical vertebrae when compared to the others

7th does not have a bifid spinous process

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what direction do thoracic vertebrae spinous processes point

downward

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what direction do spinous process point on lumbar verebrae

straight out

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where do lumbar vertebrae connect

facet joint
the meeting of the inferior and superior articular processes

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what does redicular mean

nerve root

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what two ligaments bind the vertebrae

anterior longitudinal
posterior longitudinal

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what are the three layers covering the spinal cord

pia mater
arachnoid mater
dura mater

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Where is the conus medullaris?

L1-L2

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What is the conus medullaris?

end of spinal cord

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where do we not do epidurals and spinals above

conus medularis/ L1-L2

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how many cervicle nerve roots are there

16 total (8 pairs)

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how many total nerve roots are there

31 pairs

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anterior roots are __________ nerves

motor

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posterior roots are __________ nerves

sensory

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what structure differentiatres anterior and posterior nerve roots

posterior root ganglion

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What is the filum terminale?

A pia mater extension that tethers the tip of the conus medullaris to the end of the sacrum, around S2

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what is the filum terminale made from

pia mater

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what are the layers you go through for an epidural

skin
sub q tissue
muscle
supraspinous ligament
interspinious ligament
ligamentum flavum
epidural space

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what are the layers you go through for a spinal

skin
sub q tissue
muscle
supraspinous ligament
interspinious ligament
ligamentum flavum
epidural space
dura mater
subdural space
arachnoid mater
subarachnoid space

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where is CSF found

subarachnoid space

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what is the total volume of CSF

120-150 ccs

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how much CSF is in the spinal subarachnoid space

20-30 ccs

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how much CSF is produced in a day

500ccs

what makes CSF

choroid plexus

how does lasix affect CSF production

decrease production

what is the specific gravity of CSF

1.002-1.009

what is the blood supply for the posterior spinal cord

posterior spinal arteries paired arteries fed by many radicular arteries

what is the blood supply for the anterior spinal cord

anterior spinal artery single artery, midline that has many circumfrential vessels

what can happen when anterior spinal arteryis damaged

bilateral lower extremity motor loss 2/2 damage to this artery during aorta sx or by a stray epidural needle

what is the the name of the anterior spinal artery

artery of adamkiewicz

where is the artery of adamkiewicz located on

78% on the left side of vertebral column between T8-L3

what is a high take off artery of adamkiewicz

artery comes through at T5

what are epidural veins called

Batson's Plexus

how do you make sure you are not in the epidural vein

test dose

the top of the scapula correlates with what vertebrae

the botton of the scapula correlates with what vertebrae

T7 or T7-T8 interface thoracic epidural insertion

what is Tuffiers line

A line drawn between the highest points of both iliac crests will yield either the body of L4 or the L4-L5 interspace.

What does S2 correlate with?

the caudal limit of the dural sac in most adults

what is the most prominent spinous process in the cervicle area

how do you find the sacral haitus

felt as a depression just above or between the gluteal cleft and above the coccyx

where is conus medullaris located

where is Tuffiers line located

L4-L5 interface, L4 body, correlates with the iliac crest

where does the Dural sac end

S2 correlates with superior iliac spine

where is the sacral hiatus and sacrococcygeal ligament

how does obesity affect epidural space

increased epidural fat

how does advanced age affect epidural space

decreased epidural fat, decrease dose

what are the borders of the ligamentum flavum

ligamentum magna to sacral hiatus

what is the cranial border of the epidural space

foramen magnum

what is the caudal border of the epidural space

sacrococcygeal ligament

what is the anterior border of the epidural space

posterior longitudinal ligament

what is the lateral border of the epidural space

vertebral pedicles

what is the posterior border of the epidural space

ligamentum flavum vertebral lamina

what causes a patchy block

epidural space is discontinous lacks uniformity

what can cause an epidural to have a one sided block

possible midline band in epidural space called plica mediana dorsalis

what is the most narrow portion of the epidural space

what is the widest/deepest part of the epidural space

posterior space in midlumbar region

T/F there is free fluid in the epidural space

F, if there is free fluid you are in subarachnoid space

what is the pressure of the epidural space

subatmospheric (negative)

once you inject fluid in epidural space where does it go

superior- foramen magnum inferior- sacral haitus, caudal canal lateral- intervetebral foramen to spinal nerve roots AND to dural cuff into CSF anterior-to anterior epidural space

what is the area that spinal nerve roots pass through

intervertebral foramen

what is the sight of action of epidurals

spinal nerve roots

what are the advantages of an epidural

delay in response gradual onset fewer episodes of hypotension more time to manage

how long does a spinal last

3 hrs

what kind of neuraxial block do you use for a procedure lasting 4-6 hours

epidural

what is sympathectomy

decrease SNS decreased HR, BP and vasodilation

which has a greater control of the level of sensory and motor blockade (spinal or epidural)

epidural

an increase in LA concentration causes an increase in (motor/sensory) block

motor

a decrease in LA concentration and increase in volume causes an increase in (motor/sensory) block

sensory

T/F epidurals are good for postoperative pain relief

true

do epidurals or spinal have a lower incidence of systemic hypotension

epidurals

what are disadvantages of epidurals

delay response longer procedure patchy block greater tissue trauma greater risk for local anesthetic toxicity paralysis epidural hematoma spinal HA

what is the name of the needle used in epidurals

Touhy needle

what size is a Touhy needle

16-18 g

what is the shape of a Touhy needle

curved tip

what is the angle of the Touhy needle

30*

what is the angle of the Hustead needle

15 degrees

what is the angle of the crawford needle

0 degrees

what are indications for epidurals

surgery post op pain control labor and delivery chronic pain sympathetic blockade

what are contra indications of epidural

increased ICP Coagulopathy aortic stenosis infection at insertion site watch for tattoo

what is the platelet cutoff for epidural

80,000-100,000

why are epidurals contraindicated in aortic stenosis

decreased SNS, decreases SVR, code

when do you use an epidural for a single shot injection

steroid post op pain

what layers do you pass through with midline epidural

skin and SubQ supraspinous ligament interspinous ligament ligamentum flavum epidural space

how does the supraspinous ligament feel

small pop

how does the interspinous ligament feel

gravel

how does the ligamentum flavum feel

wall

how do you place needle in Paramediaum approach

needle is inserted 1.5-2 cm lateral to spinous process at transverse process below selected level angle upwards

what layers do you go through in paramedian approach

skin and SubQ ligamentum flavum epidural space

what is the first ligament you hit in paramedian approach

ligamentum flavum

what nerve root are you at if you get thumb (first digit) numbness

what nerve root are you at if you get 2nd and 3rd digit numbness

what nerve root are you at if you get numbness in the 4th and 5th digits

what nerve root are you at if you get numbness at the nipple line

what nerve root are you at if you get numbness at the xiphoid process

what nerve root are you at if you get numbness at the umbilicus

T10

what nerve root are you at if you get numbness at the pubic symphysis

T12

what nerve root are you at if you get numbness at the anterior knee

what dermatome do you want to be at for upper abdominal surgery/C section

T4-T5 (nipple)

what dermatome do you have to be at for intestinal sx, gynecologic pelvic exam, ureter and pelvic surgery

T6-T8 (xiphoid)

what dermatome do you have to be at for TURP, vaginal delivery, hip surgery

T10 (umbilicus)

what dermatome do you have to be at for thigh surgery, lower limb amputations

what dermatome do you want to be at for foot surgery

L2-L3

what dermatome do you want to be at for perineal surgery, hemorrhoidectomy and dilation

S2-S5 (saddle block, sit up for spinal to settle)

where is the cardioaccelerator blockade

T1-T4

what nerve roots control the diphragm

C3, C4, C5

what happens with a block at level t1-t4

cardioaccelerator blockade (central sympathetic blockade) venous pooling Bradycardia

what nerve roots make up the peripheral sympathetic blockade?

T1-L2

what happens in the peripheral sympathetic blockade

venous pooling CO maintained by an increase in HR and vasoconstriction above the level of the block

how do you determine if you are in the epidural space

tough insertion through ligamentum flavum loss of resistance entering epidural space hanging drop test dose

what can happen if you put too much air in epidural space

pneumocephalus

the hanging drop helps you know you are in the

epidural space

if you hit a bone early when inserting the needle what did you hit

spinous process

if you hit a bone early how do you adjust your needle

up or down

if you hit a bone deep what did you hit

transverse process

if you hit a bone deep how do you adjust your needle

left or right

how far should epidural catheter be inside epidural space

3-5 cm into epidural space

if your needle is in 8 cm in epidural space, how far should your catheter be in

11-13

what can happen if epidural catheter is too deep in epidural space

increase chance of hitting vessel, pull catheter back

what do you inject for a test dose

3 ml of 1.5% lidocaine (45 mg) 5 mcg/ml of epi (15 mcg)

what happens with test dose if epidural catheter is in subQ/tissue

nothing will happen

what will happen with test dose if epidural catheter is in epidural space

nothing will happen

what will happen with test dose if epidural catheter is in subarachnoid space

spinal anesthesia will occur within 3 minutes

you do a test dose to confirm your epidrual and your patient has numbness in sacrum and legs, where is your epidural

subarachnoid (spinal)

what will happen with test dose if epidural catheter is in a vessel

20% raise in HR and BP within 30 sec

local anesthetic for epidurals must be _____________ free

preservative

what can be added to epidurals to lenthen the duration of the block

epi/steroids (dexamethasone)

what is the provided concentration of chloroprocaine

2-3%

what is the time of onset of chloroprocaine (epidural)

5-10 min

what is the provided concentration of lidocaine

1-2%

what is the onset of lidocaine (epidural)

10-15min

what is the provided concentration of Bupivicaine

0.25-0.5 %

what is the onset of Bupivicaine (epidural)

15-20 min

what is the provided concentration of Ropivicaine

0.25-1%

what is the time of onset of ropivicaine

10-20 min

what is Duramorph

preservative free morphine

what is the least lipid soluble narcotic you can give in epidurals

duramorph

low lipid solubility means that it has a __________ spread in CSF

higher

what is the most lipid soluble epidural narcotics

fentanyl/sufentanil

being lipid soluble means that it is taken up by

epidural fat

what opioids can you give with epidurals

Duramorph Fentanyl sufentanil Meperidine Hydromorphone

what is the general lipid solubility of Morphine

what is the onset of epidural Morphine

30-60min

what is the general lipid solubility of Hydromorphone

what is the onset of epidural Hydromorphone

15-30min

what is the general lipid solubility of Meperidine

what is the onset of epidural Meperidine

5-10 min

what is the general lipid solubility of Fentanyl

800

what is the onset of epidural Fentanyl

5 min

what are factors that affect epidural blockade

-site of injection -nerve root size -posture -local anesthetic drug, concentration, and volume -addition of epinephrine -addition of sodium bicarb

how does the addition of sodium bicarb affect epidurals

faster (shorter) onset

how does the addition of epi affect epidurals

increases DOA

what can you add to epidural for an emergency C-sec

sodium bicarb

larger nerve roots are __________ resistant to blockade

what nerve roots are the largest

L5-S1

where is epidural analgesia most concentrated

around site of injection

how does young age affect epidural dose

increased dose requirement from age 4-18

how does advancing age affect dose requirement for epidural

gradual decrease

with a patient >60yo how do you change epidural dose

decrease by 50%

what causes decreased epidural dose requirement in advancing age

decreased epidural fat content leakage through intervertebral foramina

how does pregnancy affect epidural dose

decreased requirement by 30%(smaller epidural space)

how does sever atherosclerosis affect epidural dose

decrease by 50%

what conditions causes a decreased requirement for epidural dose

pregnancy severe atherosclerosis elderly

how doe sitting vs supine effect epidural

no difference in cephalad spread maybe greater caudad when siting

how does lateral position affect epidural

favors spread of analgesia to dependent side (increased onset, longer doa, more intense block)

Dose = _________________ X_________________

Concentration x volume

increasing dose will increase block in 4 ways, what are they

^ height (volume) ^ duration ^ depth (concentration) decreased onset time

how does increasing volume affect block

increased height

how does increasing concentration affect block

decreased onset time (faster) increased intensity of motor blockade and depth of sensory blockade

addition of epinephrine to epidural LA works better with LA of ____________ concentration

lower

addition of epinephrine to epidural increases __________ and _________ of blockade

duration and depth

what kind of redose can you give to consolidate block

repeat dose of 20% 20 min after main dose

what kind of redose can you give when analgesia has receded 1-2 dermatomes

50% of original

when do you redose to increase length of epidural

when analgesia has receded 1-2 dermatomes give 50% of original dose

what happens if you wait to redose till block height decreases

could lose anesthesia intraop

how would administering the original dose of an epidural in a redose affect block

increase height

with an epidural sympathetic block occurs at _____________ level as the sensory block

the same

with an epidural motor block occurs at _____________ than the sensory block

2-4 dermatomes lower

how do you assess epidural blockade

pinprick at dermatome level (distinguish sharp) alcohol wipe (distinguish cold)

which epidural blockade method is most sensitive

alcohol wipe

how does using epidural with anesthesia affect general anesthetic requirement

decreased requirement

how does epidural with anesthesia affect post op pain

decreases

how does periop epidural affect hospital stays

decreased

which has a denser block primary or post op pain epidural

primary

what are complications of epidural anesthesia

IV injection (LAST) Subarachnoid injection (high spinal) Neurological damage infection hypotension (decreased SNS)

what is LAST

Local Anesthetic Systemic Toxicity

how does IV injection of epidural dose happen

inadvertant injection into epidural vein

what are toxic effects of LA

CNS/CV

CNS toxicity from LA occurs at ___________ levels

lower

CV toxicity from LA occurs at ___________ levels

much higher doses

which LA is least CV stable

bupivicaine

which LA is most CV stable

ropivicaine

what are negative results of epidural test dose

no numbness of feet no significant HR changes

how long do you wait after test dose to see results

3-5 min

if epidural cap comes out what do you do

pull out and replace, dont reinsert

do you pull medications through rubber top vial

how does epidural affect BP

causes hypotension

onset of hypotension is __________ in epidural than with spinal

slower

how long do crystalloid fluid last in intravascular space

30 min

ephedrine is _________ acting

indirect

what is the affect of ephedrine

increase HR increase BP

what is the max dose of ephedrine before tachphylaxis occurs

30-40 mcg

what is a normal push dose of ephedrine

10-20 mcg

what kind of drug is phenylephrine

DIRECT alpha 1 agonist

what are the effects of phenylephrine

increase BP, decreased HR

what causes the decrease in HR with phenylephrine

Baroreceptor reflex

what can you give with phenylephrine to counteract the barorecptor reflex

glycopyrrolate

what is a normal dose of phenylephrine

50-100mcg

what is a normal push dose of epi

10mcg

how do you give fluid to work with sympathomimetics in anesthesia

preload and co-load with crystalloid

what is another med we can give to treat hypotension in anesthesia

atropine?

T/F every epidural causes a CSF leak

false

what causes a CSF leak in epidural placement

SAB puncture

which is more likely to cause CSF leak misplaced epidural or spinal

epidural, needle is much larger

how do we treat CSF leak

blood patch, increases pressure and forms clot

what innervates the diaphragm

C3 C4 C5

what do intercostal muscles do for resp

used for expiration and for inspiration for pts with lung disease blockage can cause resp difficulty

T/F intercostal muscles are blocked below level of block

True

an epidural for post op pain relief (increases/decreases) resp complication

decreases

T/F epidurals have more neurologic injuries than other anesthetics

False

what causes adhesive arachnoiditis

preservative in 2-chloroprocaine

what causes epidural hematoma or abscess

bleeding or infection

what can epidural hematoma or abscess lead to

neurological damage

epidural hematoma or abscess is _______ common in epidurals than spinals, why?

more location of epidural veins larger touhy needle

for pain control give epidurals with a (high/low) concentration LA with an _________ adjuvent

low concentration opiod

what is an example of bupivicaine concentration for pain control epidural

0.125%

what is an example of narcotic/LA concentration for pain control epidural

fent 5 mcg/ml, bupivicaine 0.625%

what does epidural fent cause

itching

what is a cool way to treat epidural fent itching

narcan in 1 L bag in IV

what rate do you not go above in epidural infusion

15cc/hr

for surgery you use (higher/lower) concentrations

higher

where is the conus medullaris located

L1-L2

where is the dural sac located

where is sacral hiatus located

caudal anesthesia uses a __________ approach to the epidural space

distal

caudal anesthesia acts first on the __________ dermatomes

sacral

what is caudal anesthesia useful for

perirectal ulologic urologic hernia orthopedic surgery of the lower extremity

what is an advantage of caudal anesthesia

less medication use

what position is patient in for caudal anesthesia

prone

what is the pediatric dose of caudal block

1ml/kg

what is the adult dose of caudal block

20-30 ml

spinal anesthesia uses (more/less) volume than epidural

less

spinal anesthesia is (more/less) dense than epidural

T/F spinal anesthesia uses multiple injections

F a single shot

what are advantages of spinals

-simple -rapid -optimal for lower extremity - to decrease the intensity and duration of postop pain

what are indications for spinal

airway distortion type of procedure (rectal, TURP) OB/CSEC patient preference

what are contraindications for spinals

infection at injection site dermatologic conditions septicemia shock/sever hypovolemia spinal cord disease increased ICP blood clotting length of surgery surgical skills

what is a hyperbaric spinal injection

more dense/higher specific gravity than CSF meds fall with gravity

what is a hypobaric spinal injection

less dense/lower specific gravity than CSF floats

what is isobaric spinal injection

doesnt float or sink, same specific gravity as CSF

what position do we give spinal in

lateral decubitus

in femals the spine tilts

downward

in males the spine tilts

upward

what size are spinal needles

22-25g

spinal needle types

spinal procedure

where do we give spinal

L4-L5

spinals cause a sympathetic blockade _________ than the sensory block

2-6 dermatomes higher

spinals cause a sensory blockade _________ than the motor block

2 dermatomes higher

Distribution of spinal anesthetic in CSF is influenced by

baricity of solution contour of the spinal canal patient position

T/F volume has a large effect on spinal anesthetic

false

what effects the duration of spinal anesthetic

drug selected presence of epi/phenyl in LA

during recovery anesthesia regresses from the __________ dermatome to the __________

highest to lowest

what can the settling of LA in sacral area cause

urinary retention

what is barbatoge

mixing LA with CSF to make it isobaric

what is the DOA of tetracaine spinal

60-120 min

what is the DOA of Bupicicaine spinal

60-120

what are ways to exend the DOA of spinals

epi wash precedex

how much precedex do you put in a spinal

5 mcg

how much precedex do you put in an epidural

20 mcg

where does hyperbaric spinal settle in spine (when supine)

T 567 (lowest curvature in supine position)

where is the high point in spine when patient is supine

L2 L3 L4

how do you make a spinal solution hyperbaric

addition of dextrose

how do you achieve the greatest cephalad spread of hyperbaric spinal

supine

what is the most common spinal solution bariciy

hyperbaric

what are the commercially available hyperbaric solutions

bupivicaine 0.75% with dextrose lidocaine 5% with dextrose tetracaine 1% with dextrose

when do we use hypobaric solutions

reserved for patients undergoing perineal procedures in the prone jackknife position or undergoing hip arthroplasty where anesthetic can "float up" to nondependent operative site

what is a common technique to create a hypobaric solution

dilute the commercial 10% solution with sterile water

how do you make an isobaric solution

mix with CSF, barbitage

what is the advantage of an isobaric solution

more profound motor block more prolonged doa

is isobaric solution affected by gravity

what can we add to spinals to increase DOA

vasoconstrictors like epinephrine (0.1-0.2 mg)

what dose of fentanyl prevents itching

10-15 mcg

which is blocked first sensory or motor nerves

sensory

what does dorsiflexion of foot test

S1-S2

what does raising knees test

L2-L3

what does raising abd muscles test

T6-T12

how does motor anesthesia affect respiration

decreased ability to cough and expel secretions

above level_______ inhibits the SNS innervation to the GI tract and the unopposed PNS results in what

T5 contracted intestines and relaxed sphincters

how does SNS block affect urinary system

ureters are contracted and ureterovesical orifice is relaxed

decreaesd bleeding post block may reflect a decrease in __________

systemic BP/PVR

after doing neuraxial anesthesia you document __________ before patient leave PACU

spinal level

what is sensory level for hemorrhoidectomy

S2-S5

what is sensory level for foot surgery

L2-L3 (knee)

what is sensory level for lower extremity surgery

L1-L3 (inguinal)

what is the sensory level for Hip surgery/TURP/Vaginal delivery

T10 umbilical

what is the sensory level for lower ABD, appendectomy

T6-T7 xiphoid

what is the sensory level for upper ABD/C-sec

T4 nipple

if the fifth digit is numb, what is the segmental block and what is the significance

C8 all cardioaccelerator fibers are blocked

if the inner arm/forearm is numb, what is the segmental block and what is the significance

T1-2 some cardioaccelerator is blocked

if the apex of the axilla is numb, what is the segmental block and what is the significance

T3 easily determined landmark

if the nipple is numb, what is the segmental block and what is the significance

T4-5 possible cardioaccelerator block

if the tip of xiphoid is numb, what is the segmental block and what is the significance

T7 splanchnics blocked

if the umbilicus is numb, what is the segmental block and what is the significance

T10 SNS block limited to legs

if the inguinal ligament is numb, what is the segmental block and what is the significance

T12 No SNS block

if the outer side of foot is numb, what is the segmental block and what is the significance

S1 confirms block of most difficult root to anesthetize

what can cause a failed spinal anesthetic

inability to identify subarachnoid space failure to inject all or part of the local anesthetic solution maldistribution of the local anesthetic bad local anesthetic

if you have to repeat a dose of spinal anesthetic, you shout assume the patient received _________ of the first dose

all

what causes hypotension in spinals

SNS block -partially due to decrease in SVR -mostly due to decrease in venous return to the heart and decreased CO

what percent of spinal patients have bradycardia

10-15%

what happens with high spinal anesthesia

systemic hypotension nausea agitation

what happens with ischemic paralysis of the medullary ventilatory centers

apnea LOC profound hypotension decrease in CBF

what is treatment for high spinal anesthesia

1. Maintain airway and ventilation 2. Sympathomimetics and IV fluids 3. trendelenburg to increase venous return NO reverse trendelenburg 2/2 decreased venous return 4. intubation

what is cauda Equina syndrome

neurotoxity from high concentration of LA

what are s/s cauda equina

bowel and bladder dysfunction sensory deficits weakness paralysis

what is treatment for cauda equina

supportive

what are signs and symptoms of transient neurologic syndrome

severe back and butt pain that radiates to both legs

when do transient neurologic system develop

6-36 hours, persists from 1-7 days

what is treatment for transient neurologic syndrome

NSAIDs, opiod analgesics, trigger point injections

what is CSE

combined spinal epidural

what is benefit of Dural hole with epidural

allows local/opioid to leak in to subarachnoid space

T/F catheter is more likely to fail in CSE

F, it is less likely to fail

do you test dose a CSE

what is CSE dosing for spinal

1.75-2.5 mg bupivicaine 10-15 mcg fentanyl precedex 5 mcg

does isobaric have faster/slower onset than hyperbaric spinal

faster

what is a DPE

CSE without injection of medication into spinal

what does DPE help you confirm

confirm you are not in subdural space by poking hole in dura and seeing CSF

what is benefit of DPE hole in dura

increased spread of local (block of S1 or higher) decreased hot spots decreased unilateral blocks possible faster onset

what is benefit of intermittent bolusus over continous infusion of epidural

continuous only comes out of the proximal port, less effective block boluses come out of multiple ports, better coverage

T/F spread of epidural medication is better with continous infusion

F, it is better with bolus

boluses helps epidural medication spread to ________ and ________

DRG segmented nerves

in epidural fentanyl boluses act on the ___________ while infusion act on____________

spinal supraspinal

what are pros of spinal sonography

correct spinal level (obese patients) increased 1 stick rate decrease need for needle redirects correct for scoliosis determine depth of ligamentum flavum/dura

what percentage of spinal levels are correctly identified by palpation

30%

what percentage of spinal levels are correctly identified by ultrasound

71%

ultrasound of spine pic