LA - Epidural

Question 1

Which has a higher incidence of PDPH: spinal or epidural?

Answer 1

spinal

Question 2

Cause of PDPH

Answer 2

Leakage of CSF from dura/arachnoid

-needle size correlated w/ incidence/intensity of HA

Question 3

Wet tap

Answer 3

epidural inserted too far

Question 4

Which has lower incidence hypotension: epidural or spinal? Why?

Answer 4

Epidural

1. strength of autonomic blockade not as strong
2. spinal has higher autonomic blockade than sensory (epidural is same level)

Question 5

Main site of action for epidural LA

Answer 5

nerve root

Question 6

Which has slowest onset: SAB or Epidural?

Answer 6

Epidural

Question 7

Why does epidural have slower onset?

Answer 7

LA has to diffuse accross dura (meninges) to reach nerve root

Question 8

Important characteristic of epidural veins

Answer 8

valveless

• located lateral to midline, anterior
• higher risk of hitting w/ paramedial approach

Question 9

Pregnant individuals + those with increased intra-abdominal pressure have what alteration in epidural area

Answer 9

Engorged epidural veins, decreased epidural volume

Question 10

How far in should epidural catheter be secured?

Answer 10

Additional 5cm from where loss of resistance is felt.

i.e. Catheter says 5 when loss of resistance felt: secure at 10 cm

Question 11

Epidural catheter should be positionef

Answer 11

bevel UP

-so catheter migrates cephalad

Question 12

primary limiting membrane for epidural

Answer 12

arachnoid mater

Question 13

Epidurals cause what type of blockade?

Answer 13

Segmental

-nerve roots closest to site of injection are blocked/anesthetized best

Question 14

Spread of spinal anesthetic is dependent on

Answer 14

1. baricity
2. position of patient
3. dose (not as much)

Question 15

Spread of epidural anesthesia is dependent on

Answer 15

volume

*only isobaric LA

Question 16

2 main differences between spinal and epidural

Answer 16

Epidural:

1. onset of sympathetic block is slower (less likely to have abrupt HOTN)
2. Sympathetic block @ same level as sensory, motor block = 4 levels below

Question 17

Sequence of blockade

Answer 17

1. peripheral vasodilation + HOTN
2. Loss of pain + temp
3. Loss of proprioception
4. Motor weakness
5. Paralysis

Question 18

Peripheral vasodilation + HOTN occurs d/t blockade of which fibers?

Answer 18

B Fibers

Question 19

Loss of pain + temp occurs d/t blockade of which fibers?

Answer 19

A-delta + C fibers

Question 20

Loss of proprioception occurs d/t blockade of which fibers?

Answer 20

A-alpha

Question 21

Motor weakness occurs d/t blockade of which fibers?

Answer 21

A gamme

Question 22

Paralysis occurs d/t blockade of which fibers?

Answer 22

A-beta

Question 23

How do you know you’re in the epidural space?

Answer 23

Loss of resistance
“LOR”
(past Ligamentum Flavum)

Question 24

How far in should catheter be placed for epidural?

Answer 24

10 cm

• Epidural space: 4-6cm from skin
• want 3-5 cm catheter inside epidural space

Question 25

After LOR felt, describe next steps of epidural placement

Answer 25

1. Remove stylet from needle 2. Attach syringe, verify no blood/CSF 3. Note distance on needle - insert catheter 1 cm at a time 4. Resistance felt at tip of needle, continue 3-5cm 5. Withdraw needle, maintain catheter at insertion site

Question 26

After epidural catheter is placed, what must be done?

Answer 26

Tape catheter over shoulder to confirm no movement of catheter even if patient is moved

Question 27

Unable to thread catheter - what to do

Answer 27

Rotate needle, try to advance catheter again

Question 28

If epidural placed, aspiration shows blood - what is happening?

Answer 28

Epidural is in vein - remove! Try again

Question 29

What must be done every time epidural catheter is accessed?

Answer 29

Aspirate for minimum 5 seconds Good = nothing seen Bad = blood (vein) or CSF (SA space)

Question 30

What is done to confirm placement of epidural?

Answer 30

Epidural test dose

Question 31

Why is an epidural test dose performed?

Answer 31

To confirm placement | -aspiration may apply negative pressure + result in false negatives

Question 32

Epidural test dose consists of

Answer 32

3mL 1.5% Lidocaine + 5mcg/mL Epi (1:200,000)

Question 33

After test dose - what is seen if catheter is intravascular?

Answer 33

HR increases 10-15% within 1 min | *pt having contractions: perform after contraction

Question 34

After test dose - what is seen if catheter is intrathecal?

Answer 34

Sacral anesthesia develops w/in 3-5min tested by pin prick

Question 35

Epidural dosing may begin when?

Answer 35

After test-dose administered + verified catheter is in epidural space

Question 36

Epidurals should be administered how

Answer 36

Dose in 3-5 cc increments | -intermittent injection or continuous infusion

Question 37

Key determinant for height (spread) of epidural block

Answer 37

Volume of LA given

Question 38

Key determinant for density/completeness of block

Answer 38

Concentration of LA

Question 39

Tx: High/total spinal

Answer 39

supportive, 100% fiO2, intubate, fluids, pressors * avoid vasopressin * avoid more LA (Lido) obvi

Question 40

Epidural hematoma - s/s

Answer 40

sudden onset** bilateral complaints (chief sign) leg/back pain lower extremity weakness

Question 41

Epidural hematoma dx

Answer 41

CT scan

Question 42

Epidural hematoma Tx

Answer 42

surgical decompression w/in 12h

Question 43

most common cause of PDPH

Answer 43

dural puncture "wet tap"

Question 44

PDPH Tx

Answer 44

Epidural blood patch