neuraxial blocks part 2

Question 1

4 key SE of neuraxial opioids

Answer 1

1. pruritis
2. urinary retention
3. resp depression
4. n/v

Question 2

MOA of pruritis during neuraxial blockade

Answer 2

stimulation of opioid receptors in trigeminal nucleus or some other type of opioid triggered neural process

Question 3

MOA of early versus late stage resp depression (most often both in hydrophilic)

Answer 3

early (<6h) results from systemic absorption
late (>6h) results from tendency of hydrophilic opioids to ascent towards brainstem where they can inhibit resp center

Question 4

resp depression is more common with (6)

Answer 4

high opioid doses
co administered sedatives
low lipid solubility
advanced age
opioid naivety
increased ITP

Question 5

urinary retention from neuraxial opioids MOA

Answer 5

inhibition of sacral PSNS tone aka SNS tone is winning

Question 6

n/v from neuraxial opioids MOA

Answer 6

caused by activation of opioid receptors in the area postrema of medulla and vestibular apparatus

Question 7

transfer of opioids from epidural space to breast milk

Answer 7

minimal

Question 8

which LA decreases efficacy of neuraxial opioids

Answer 8

2 chlorprocaine

Question 9

neuraxial blocks are contraindicated if platelet count is what and coags are

Answer 9

platelet count <100,000
coags are 2x normal value (aPTT, PT, or bleeding time)

Question 10

contraindications to neuraxial opioids include

Answer 10

-increase in ICP
-sepsis
-infection at puncture site
-hypovolemia
-valve lesions with fixed SV
-scoliosis, arthritis, spinal fusions, osteoporosis
-full stomach
-peripheral neuropathy (theory that patients are more susceptible to injury)
-MS
-spina bifida

Question 11

ID this type of spinal needle

Answer 11

quincke

Question 12

ID this type of spinal needle

Answer 12

sprotte

Question 13

ID this type of spinal needle

Answer 13

whitacre

Question 14

ID this type of spinal needle

Answer 14

green

Question 15

ID 3 types of spinal needles

Answer 15

cutting tip (quincke)
pencil point (sprotte, whitacre)
rounded bevel (green)

Question 16

ID these 3 types of epidural needles

Answer 16

Question 17

how deep is epidural space

Answer 17

3-5cm from skin surface

Question 18

absolute contraindications to caudal anesthesia

Answer 18

spina bifida
myelomeningocele of sacrum
meningitis

Question 19

relative contraindications to caudal anesthesia

Answer 19

pilondial cyst
abnormal superficial landmarks
hydrocephalus
intracranial tumor
progressive degenerative neuropathy

Question 20

caudal block technique
position of patient
landmarks
needle type

Answer 20

-performed in lateral or prone position
-in lateral position (Simms) top leg flexed more than bottom leg
-in prone position, small roll should be placed under iliac crests with legs in frog position
-using PSIS and sacral hiatus as land marks, envision equilateral triangle with apex of triangle at sacral hiatus
-use 22 or 25g needle or 20g IVC at 45 degree angle angling cephalad
-advance until you hear a pop then drop the angle and advance

Question 21

you should not use ______ for loss of resistance in children during epidurals

Answer 21

air (risk of air embolism)

Question 22

resistance to injection during caudal block suggests needle is in

Answer 22

subperiosteal area

Question 23

what feeling may patient experience as a caudal epidural is setting up

Answer 23

feeling of fullness in sacrum

Question 24

placing the needle tip beyond ______ increases the risk of of dural puncture during caudal block

Answer 24

S2-S3

Question 25

during a caudal block, how to you angle the needle

Answer 25

once you feel a pop, drop the angle from 45 degrees

Question 26

how to dose a caudal block
pediatric
adult

Answer 26

peds: .5mL/kg
adult 12-15mL

Question 27

how to dose a sacral to low thoracic block (T10)
pediatric
adult

Answer 27

peds: 1mL/kg
adult: 20-30mL

Question 28

how to dose a sacral to mid thoracic anesthetic
pediatric
adult

Answer 28

peds: 1.25mL/kg
adult: n/a

Question 29

peds dose maximums for caudal block

Answer 29

dont exceed total dose of 2.5-3mg/kg

Question 30

common procedures where a caudal block is useful

Answer 30

circumcision
hypospadias repair
anal surgery
inguinal herniorrhaphy
low thoracic surgery

Question 31

presenting symptoms of epidural hematoma

Answer 31

LE weakness, numbness, low back pain, bowel and bladder dysfunction
surgical decompression within 8 hours is the best chance of recovery
risk of epidural hematoma is similar during block placement and catheter removal