Olson, Peripheral Nerve Blocks

Front 1

Connection of the CNS with all peripheral structures by:
__ pairs of cranial nerves &
__ pairs of spinal nerves

Back 1

12 pairs of cranial nerves
31 pairs of spinal nerves

Front 2

What is the goal of a peripheral nerve block?

Back 2

Goal is to infuse local anesthetic in fascial plane wherein targeted nerves are located

Front 3

What are the four techniques for peripheral nerve blocks?

Back 3

Nerve stimulation
Paresthesia
Field block (volume block)
Ultrasound guidance

Front 4

What are the 3 Sacral Plexus Nerve Blocks?

Back 4

Sciatic Nerve Block
Popliteal Nerve Block
Ankle Block

Front 5

What part of the neuron carries affarent signals?

Back 5

Dendrites

Front 6

What part of the neuron carries efferent signals?

Back 6

Axons

Front 7

What are the three protective layers of the neuron in order from outermost to innermost?

Back 7

Epineurium (covers the entire pheripheral nerve)
Perineurium (covers each fascicle)
Endoneurium (covers each nerve fiber)

Front 8

What are two benefits of a peripheral nerve block compared to GA?

Back 8

- Less PONV
- No MH
- Better tolerated in "sick" patients

Front 9

What are two disadvantages of peripheral nerve blocks compared to GA?

Back 9

Risks of:
- Systemic toxicity
- Chronic paresthesia
- Nerve damage
- Respiratory failure (phrenic nerve block)

Front 10

What are 3 contraindications to doing a peripheral nerve block?

Back 10

- uncooperative patient
- bleeding diathesis
- infection
- local toxicity
- peripheral neuropathy

Front 11

What is the greatest immediate risk of peripheral nerve blocks?

Back 11

IV injection - Toxicity

Front 12

How do you avoid complications of peripheral nerve blocks?

Back 12

- give a test dose
- increment dosing
- frequent intermittent aspiration
- immobilize needle

Front 13

What are the common locals & concentrations used for surgical anesthesia (4)?

Back 13

- 1.5-2% Lidocaine
- 2% Mepivacaine
- 0.5% Bupivacaine
- 0.5% Ropivacaine

Front 14

A successful peripheral nerve block is more likely if the needle is close to the _______. (endoneurium, perineurium, or epineurium)

Back 14

Epineurium

Front 15

What is a field block?

Back 15

It is a volume block. A large amount of local is injected in the "general area" of the nerve.
It is the oldest technique

Front 16

Where are field blocks used?

Back 16

- Ankle block
- Superficial cervical plexus

Front 17

What is the paresthesia technique for peripheral nerve blocking?

Back 17

The needle is inserted until direct needle contact causes paresthesia in the area of sensory distribution.
Use a blunt tip needle
When the patient feels the pain pull back slightly and inject local.

Front 18

What is the nerve stimulation technique used for peripheral nerve blocking?

Back 18

A nerve stimulator is attached to an electrode, grouded to patient, and to an insulated needle.
The stimulator is set to the desired amount (1-1.5 generally).
The needle is inserted until the desired nerve is stimulated causing the muscle to twitch. The stimulator is turned down, goal is to still have twitches at 0.5.
If twitches still present at 0.3 or less it is likely you are in the nerve, pull needle back slightly.
Inject local (twitch will go away after 1-2ml injected)

Front 19

What are the benefits of continuous peripheral nerve blocks?

Back 19

- They provide ongoing analgesia
- They can stay in place for 3-5 days
- Have low complication rate
- Improved outcomes & decreased morbidity w/some procedures