EPIDURAL ANESTHESIA

Question 1

Spinal V Epidural
_ provide total sensorimotor blocks, whereas _ produce segmental blocks

Answer 1

spinals
epidurals

Question 2

Spinal V Epidural
-lower risk of PDPH
-lower risk of HOTN

Answer 2

Epidurals are lower risk for both

Question 3

Spinal V Epidural
which is longer to perform and achieve?

Answer 3

epidurals

Question 4

Spinal V Epidural
-MOA is diffusion dependent and use higher volumes of LA

Answer 4

epidural

Question 5

Spinal V Epidural
-must be given below L1-L2
-can be given anywhere on spinal column

Answer 5

below L1/L2 = spinal

anywhere = epidural

Question 6

Epidural space contains: 5 items

Answer 6

-FAT
-nerves
-lymph tissue
-connective tissue
-vessels (veins mainly-risk of LAST)

Question 7

Borders of epidural space
-superior
-inferior
-anterior
-posterior
-lateral

Answer 7

superior = foramen magnum

inferior = sacrococcygeal membrane

ant = intervertebral disks and vertebral bodies

post = LF and laminae

lateral = pedicles + intervertebral foramen ( where spinal nerves exit)

Question 8

Depth of skin to LF in lumbar region using midline approach is _ - _ cm

Answer 8

4-5cm

IN GENERAL 4-6CM

Question 9

LF thickness in different regions
-cervical
-thoracic
-lumbar

Answer 9

C = 4-6mm

T = 3-5mm

L = 5-6mm(0.5cm)

Question 10

Sites of action of LA in epidural space: 5 items

Answer 10

• SPINAL NERVE ROOTS (PRIMARY)
  -rootlets
  -mixed spinal nerves in epidural space
  -DRG
  -SC
  -brain (once reaching SC, impulses dont go to brain)

Question 11

Spinal nerve roots are NOT directly at the site of injection for epidurals, what is in the way or influencing LA reaching its intended site in the CSF?

Answer 11

dura
-functions as a barrier

absorption into circulatory system
-tox risk (large venous network)

retention into fat
-acts as a reservoir and redistributes over time

Question 12

LA injected epidurally spreads more _ (horizontally / vertically) and more _ (cephalad/caudal) than _ (cephalad/caudal)

Answer 12

more horizontal than vertical

more cephalad than caudal

Question 13

The most important route of entry to the site of action for LA with epidurals is the _ _ _

Answer 13

dural cuff regions
-contain proliferations of arachnoid villi and granulations, making dura less thick, allowing rapid diffusion through the dura into CSF

Question 14

Dose (volume x conc) matching: (give a higher-dose, concentration, volume)
-want more vertical spread
-want longer block and analgesia
-want more intense block and shorter onset

Answer 14

higher vertical spread = higher volume

longer block and analgesia = higher dose

more intense motor block and shorter onset = higher concentration