Regional anesthesia

Question 1

What particular part of the brachial plexus is targeted by the supraclavicular block?

Answer 1

The trunks/divisions appear as a cluster of grapes (hypoechoic circles) lateral the the pulsating subclavian artery and superior to the first rib.

Question 2

Why is the supraclavicular block not indicated for shoulder surgery?

Answer 2

This block does not supply complete coverage because the suprascapular nerve which arises from the upper trunk (C5-C6) is often missed.

Question 3

Why is the ultrasound used during the supraclavicular block?

Answer 3

When performing this block, the needle is in very close proximity to the pleura and the subclavian artery.

Question 4

The supraclavicular block is appropriate for what types of surgical procedures?

Answer 4

The supraclavicular block provides analgesia for surgical procedures of the upper arm, elbow, wrist and hand

Question 5

When using the landmark technique and nerve stimulator to perform a supraclavicular block, what is an acceptable twitch?

Answer 5

Finger twitch - flexion and extension

Unacceptable responses include: pectoralis (direct stim), biceps (musculocutaneous nerve) and deltoid (axillary nerve)

Question 6

What are the signs of Horner’s syndrome

Answer 6

Ptosis, miosis, anhidrosis. These symptoms are due to the proximity of the supraclavicular block to the stellate ganglion.

Question 7

How can the ultrasound be used to assess the status of pleura if a pneumothorax is suspected?

Answer 7

If lung sliding is present, the pleura is intact. If you do not see lung sliding, the patient may have a pneumothorax. A CXR should be used to rule this out. Symptoms may include cough, chest pain, and dyspnea (late sign) after the block.

Question 8

During a subclavian block, how often can the patient experience phrenic paralysis or Horner’s syndrome?

Answer 8

About 50% of the time! Watch for signs of ptosis, miosis and anhidrosis.

Question 9

What part of the brachial plexus is targeted during an infraclavicular block?

Answer 9

The cords. Blocking the brachial plexus at the level of the cords is a good alternative to the supraclavicular block in patients with respiratory insufficiency d/t the decreased risk of phrenic nerve blockade

Question 10

What are the 3 most common errors that occur and increase the risk of pneumothorax during an infraclavicular block?

Answer 10

• needle insertion too medial
• directing the needle medially
• inserting the needle too deep (>6cm)

Question 11

When the median nerve is stimulated, what is the correct muscle response to stimulation?

Answer 11

Flexion of the first 3 1/2 digits and opposition of the thumb

Question 12

When stimulating the radial nerve, what is the correct response to stimulation?

Answer 12

Extension of the wrist and digits along with abduction of the thumb

Question 13

When targeting the ulnar nerve, what is the correct response to nerve stimulation?

Answer 13

Flexion of the 4th and 5th digits and ADDuction of the thumb

Question 14

Why is the infraclavicular block considered to be the most painful block?

Answer 14

Because of the multiple muscle layers that must be traversed for a successful block. These muscles include the pectoralis major and minor. Injecting additional subcutaneous local can help improve patient experience

Question 15

Why is bleeding from the subclavian arter/vein during an infraclavicular block so detrimental?

Answer 15

Because this area can be very difficult to compress and can result in significant bleeding/hematoma.

Question 16

Why is there an increased risk of LAST during infraclavicular blocks?

Answer 16

Because the needle has to be directed in such a steep angle and it can become difficult to identify the needle tip. Inadvertent injection into vasculature may occur leading to LAST. Frequent aspiration is necessary to decrease risk

Question 17

Of these three blocks (supraclavicular, infraclavicular and interscalene), which block is considered to pose the least risk of pneumothorax?

Answer 17

Infraclavicular block. Although the risk is less, it can still happen. Inserting the needle in a slight lateral direction decreases the risk of pneumothorax

Question 18

What part of the brachial plexus does the axillary block target? List all components

Answer 18

The terminal branches. It targets 4 of the 5 terminal branches - all except the axillary nerve. This block does not cover skin on the medial upper arm (intercostobrachial n.) or the skin over the deltoid (axillary n.)

Question 19

List the borders of the femoral triangle

Answer 19

Sartorius muscle
Adductor longus muscle
Inguinal ligament

“SAIL”
The femoral n. arises from the posterior divisions of L2-4. The roots merge in the psoas major and form the nerve. It then courses between the psoas and iliacus muscles and passes under the inguinal ligament

Question 20

Once under the inguinal ligament, the femoral n. divides into anterior and posterior divisions. What does the anterior branch supply?

Answer 20

The ventral surface of the thigh and sartorius muscle

Question 21

Once under the inguinal ligament, the femoral n. divides into anterior and posterior divisions. What does the posterior branch supply?

Answer 21

The quadriceps muscle, the knee join and the medial ligament. The saphenous n. arises from the posterior branch

Question 22

When combined with what block, the femoral nerve block provides almost complete coverage of the lower extremity?

Answer 22

The sciatic nerve block. The femoral nerve block alone however does provide anesthesia/analgesia for hip, femur, quad and knee procedures.

Question 23

What two structures must be penetrated to ensure an effective femoral nerve block?

Answer 23

The fascia lata and fascia iliaca. This is regardless of technique (landmark or ultrasound)

Question 24

If you are performing a femoral nerve block using landmark technique and the inner thigh starts to twitch, what has happened?

Answer 24

The needle is too superficial and medial. This causes stimulation of the sartorius muscle rather than the “patellar snap” that should occur with a proper block.

Question 25

What are the boundaries of the adductor canal?

Answer 25

Roof: sartorius
Lateral wall: vastus medialis
Remainder: adductor longus or magnus depending on level scanned

The adductor canal starts at the base of the femoral triangle and ends at the adductor hiatus

Question 26

List some indications for an adductor canal block:

Answer 26

ACL
MCL
patella fracture
vein stripping and harvesting
Supplementation to a sciatic block for foot/ankle surgery

Question 27

What increases the likelihood of quadriceps weakness when performing an adductor canal block?

Answer 27

More likely with proximal injections and injections with volumes greater than 20ml

Question 28

When combined with what block, the popliteal sciatic block provides complete coverage of the lower extremity below the knee?

Answer 28

The saphenous nerve block

Question 29

When performing a popliteal sciatic block, where is the ideal location for local anesthetic placement?

Answer 29

Where the sciatic nerve divides into the tibial nerve and common peroneal nerve.

Question 30

What motor response will you obtain when blocking the common peroneal and tibial nerve?

Answer 30

Tibial: inversion, & plantar flexion
Common peroneal: eversion & dorsiflexion
“TIPPED”