Neuraxial Anesthesia

Question 1

What can happen with degenerative disc disease?

Answer 1

It decrease the size of the intervertebral foramen, and can cause nerve compression

Question 2

What is Batson’s plexus?

Answer 2

Network of epidural veins

Question 3

Why do pregnancy and obesity decrease the epidural space?

Answer 3

Increased intraabdominal pressure puts back pressure on the epidural veins. This increases the blood volume in the epidural space and decreases the rest of the room within the space

Question 4

The dural sac ends here

Answer 4

Adult = S2 (level of the superior iliac spines)
Infant = S3

Question 5

Anterior nerve roots carry

Answer 5

Motor and autonomic information

Question 6

These fibers are NOT myelinated

Answer 6

C fibers

Question 7

Order of types of fibers blocked

Answer 7

1- Autonomic
2- Sensory
3- Motor

Question 8

Why is autonomic blockade higher than motor in spinals? How much higher?

Answer 8

Autonomic fibers are more sensitive to LA, so they get blocked with lower concentrations.

2-6 dermatomes higher

Question 9

How much higher is sensory block than motor block in spinals?

Answer 9

2 dermatomes higher

Question 10

Difference between motor block and autonomic block in epidurals?

Answer 10

There is none! They are at the same level

Question 11

Difference between motor and sensory block in epidurals

Answer 11

Sensory is 2-4 dermatomes higher

Question 12

Vasodilation that occurs with sympathectomy

Answer 12

Both arterial and venous, but MOSTLY VENOUS. Results in decreased venous return, decreased CO, decreased BP, etc.

Question 13

Why might your healthy patient be c/o dyspnea after neuraxial anesthesia

Answer 13

D/t loss of chest proprioception

Question 14

Why may you have drowsiness with neuraxial?

Answer 14

Because there is less input arriving to the RAS

Question 15

Effect of neuraxial on GI system

Answer 15

Blocks SNS, but PSNS from CNX is unaffected and runs unopposed. Results in increased peristalsis and sphincter relaxation.

Question 16

Why is full stomach a risk with neuraxial?

Answer 16

B/c the low BP from sympathectomy can cause N/V

Question 17

MS and neuraxial

Answer 17

Looks like OK with epidural, but MS may slightly exacerbate with spinal. No real data to support this though. Explain risk of exacerbation to your patient.

Question 18

Spec gravity of CSF

Answer 18

1.002-1.009

Question 19

LAs in dextrose are hyperbaric, while those in water are hypobaric. What is the exception to this?

Answer 19

Procaine 10% in water is actually HYPERBARIC

Question 20

Due to natural curvature of the spine, when a spinal is placed, LA pools and you get sensory block up to what dermatome?

Answer 20

T4

Question 21

Absolute contraindications to Caudal anesthesia

Answer 21

Spina bifida
Meningomyelocele of the sacrum
Meningitis

Question 22

This additive can provide analgesia that is equal to epidural opioids

Answer 22

Clonidine (1mcg/kg)

Question 23

Any volume of bupiv, ropiv, or levobupiv may be used in peds as long as the total dose doesn’t exceed

Answer 23

2.5mg/kg

Question 24

Where do neuraxial opioids affect pain transmission?

Answer 24

Substantia gelatinosa Lamina II of the dorsal horn

Question 25

Effect of combining opioids with LAs

Answer 25

Denser block

Question 26

Neuraxial opioids do NOT cause

Answer 26

Sympathectomy
Motor Block
Changes in proprioception

Question 27

Most common SE of neuraxial opioids administration

Answer 27

Pruritis

Question 28

Does benadryl work for neuraxial opioid itching?

Answer 28

No

Only narcan

Question 29

Hydrophilic drugs and rest depression

Answer 29

Biphasic

Early (6 hours) due to tendency to rise towards the brain

Question 30

Opioids and chlorprocaine

Answer 30

2-Chlorprocaine decreases efficacy of epidural opioids

Question 31

Herpes and morphine

Answer 31

May reactivate HSV Type I d/t stimulation at the trigeminal nucleus

Question 32

Opioids and breast milk

Answer 32

Minimal opioids is transferred from epidural space to breast milk

Question 33

Examples of cutting needles

Answer 33

Pitkin
Green
Quinke

Question 34

PDPH is more common in this population

Answer 34

Young, pregnant females

Question 35

S/S of epidural hematoma

Answer 35

Weakness, numbness, lower back pain, and bowel and bladder dysfunction

Question 36

Conus Medullaris ends at

Answer 36

Adults L1-2
Infants L3

For the dural SAC:
Adults S2
Infants S3

Question 37

Cauda Equina Syndrome vs. Transient Neurologic Symptoms (TNS)

Answer 37

Cauda Equina

• NEUROTOXICITY d/t exposure to high concentrations of LA
• S/S = bowel and bladder dysfunction, sensory deficits, and weakness/paralysis ==> i.e. major nerve damage!
• Treatment is supportive (not much you can do)

TNS

• NOT from nerve toxicity ==> usually due to positioning, stretching of sciatic nerve, myofascial strain, and muscle spasm.
• Lidocaine and lithotomy position increases risk
• See severe back and butt pain that radiates to both legs
• Starts 3-36 hours after surgery, and lasts 1-7 days
• Treat with NSAIDS, opioids, and trigger point injections

Question 38

Apnea after a spinal is generally due to

Answer 38

Cerebral hypoperfusion! (Blood pressure is too low!)

Question 39

Level of cardiac SNS innervation

Answer 39

T1-4

Question 40

Level of vascular SNS innervation

Answer 40

T1-L2

Question 41

S/S of PDPH

Answer 41

Fronto-occipital HA, tinnitus, and N/V

Question 42

How do you know when you have given enough blood for an epidural blood patch?

Answer 42

Once the patient starts to feel pressure in their back, buttocks, or legs

Question 43

Organism that most commonly causes post-spinal bacterial meningitis

Answer 43

Streptococcus viridans

This is found in the mouth, and is why we wear masks during placement

Question 44

Best disinfectant for neuraxial anesthesia

Answer 44

Combo of iodine and isopropyl alcohol

Question 45

Lab cutoffs for neuraxial blocks

Answer 45

Plts 2x normal