Upper Extremity Blocks (pt 1)

Question 1

What are the terminal branches of the Brachial Plexus?

Answer 1

Musculocutaneous
Axillary
Radial
Median
Ulnar

Question 2

Describe the origin and innervations of the Musculocutaneous nerve.

Answer 2

-C5,C6,C7 nerve roots
-Lateral cord
-Motor innervation to the Arm Flexors: Coracobrachialis, Biceps Brachii, and Brachialis muscles
-Sensory innervation to the Lateral Antebrachial Cutaneous nerve (skin over lateral area of forearm)

Has to be blocked separately during an Axillary Block

Question 3

Describe the origin and innervations of the Axillary nerve.

Answer 3

-C5,C6
-Posterior cord
-Follows the Posterior Circumflex Humoral artery
-Motor innervation to the Deltoid and Teres Minor muscles
-Sensory innervation to the Anterior/Lateral shoulder

Can be used for shoulder surgeries when trying to avoid interscalene due to risk of phrenic nerve (diaphragm) involvement.

Question 4

Describe the origin and innervations of the Radial nerve.

Answer 4

-C5 - C8, inconsistent T1 contribution
-Posterior Cord
-Largest branch of the Brachial Plexus

Motor innervation to:
-Extensor muscles of arm & forearm: triceps brachii, extensor carpi radialis, extensor carpi ulnaris
-Brachioradialis
-Digital extensors
-Abductor Pollicis

Sensory innervation to the posteriolateral arm, posterior forearm, and posterior digits 1-3
-Sensory to backside of arm basically

Question 5

Describe the origin and innervations of the Median nerve.

Answer 5

-C6 -T1 with inconsistent contribution from C5.
-Medial and Lateral Cords

Motor innervation to:
-Flexor muscles of the forearm: Flexor carpi radialis and palmaris longus
-Pronator Quadratus
-Pronator Teres
-Digital Flexors

Sensory innervation to:
-Skin on anteriolateral hand
-Lateral aspect of 4th digit

Question 6

Describe the origin and innervations of the Ulnar nerve.

Answer 6

-C8, T1
-Medial Cord
-Motor innervation to: flexor carpi ulnaris, Adductor Pollicis, and Small digital muscles
-Sensory innervation to the skin over the medial surface of the hand.

Usually spared during interscalene block (this is why interscalene approach is a poor choice for surgeries below the elbow).

Question 7

What are the indications for the Interscalene Block (ISB)?

Answer 7

Covers shoulder, arm, and proximal forearm.
-Shoulder Arthroscopy
-Rotator cuff repair
-Total shoulder arthroplasty
-Triceps and bicep reattachment
-Reduction of shoulder dislocation
-Proximal humerus fractures

Shoulder to just below elbow

Question 8

What are the absolute contraindications for an Interscalene Block (ISB)?

Answer 8

-Patient refusal
-Allergy to local anesthetics
-Local infection at or near the needle insertion site
-Bilateral Blocks: Risk for Bilateral phrenic nerve blockade and Bilateral Pneumothorax.
NEVER EVER do bilateral blocks with an interscalene approach (could knock out both sides of the Diaphragm).

Question 9

What are the relative contraindications for an Interscalene Block (ISB)?

Answer 9

-Uncooperative patient
-Severe respiratory compromise
-Coagulopathy or Anticoagulation
-Traumatic nerve injury in the upper extremity or neck
-Preexisting neurodeficits in the distribution of the block
-Previous surgery in the neck that may distort brachial plexus anatomy

If you already have a nerve injury, the likelihood of it worsening due to a block is high.

Question 10

What dermatomes are covered by an ISB?

Answer 10

-C5 to C7 Dense anesthesia (superior and middle trunks)
-C8, T1 poor coverage, if at all (Inferior trunk)

“Ulnar Sparing”

Question 11

What level of the Brachial Plexus are you blocking with an ISB?

Answer 11

Roots/Trunks

Question 12

The Brachial Plexus is in close proximity to what two structures that could cause serious complications during the block?

Answer 12

-Phrenic Nerve
-Vertebral Artery

Question 13

What surface anatomy do you identify with an ISB?

Answer 13

-Clavicle
-Posterior border of the SCM
-External Jugular vein (usually crosses the interscalene groove at the trunks)
-Cricoid cartilage (C6 vertebrae)

Question 14

Where is the Interscalene groove located?

Answer 14

Interscalene groove lies just posterior to SCM m., right around C6 vertebrae (C6 vertebrae is identified by cricothyroid cartilage)

Question 15

What LA is commonly used with an ISB?

Answer 15

-Usually 0.5% Bupivicaine is used
-Can use Ropivicaine or Lidocaine
-Normally 30-40 mL LA used

Question 16

How do you find the Brachial Plexus using an US (ISB technique)?

Answer 16

-Find the sternal notch and acromion process of clavicle
-Rest probe above clavicle at midclavicular line
-Find Subclavian Artery
-Sweep probe cephalic (up neck) until you see Ant/Mid Scalene.
-will see C5-7 roots between scalenes
-Move needle under plexus to deposit LA.
-Risk of injuring partially anesthetized plexus always present
-Goal is to have plexus look like an island floating in LA.
-Can do a single shot of 15- 30mL to dilate space, then place catheter

Question 17

What are complications/risks associated with the ISB?

Answer 17

-Incidental blockade: Phrenic N, Recurrent laryngeal N, and Cervical sympathetic ganglion (Horner’s Syndrome)
-Infection
-Hematoma
-Intravascular injection
-LA Toxicity
-Total spinal anesthesia
-Pneumothorax
-Nerve injury

Question 18

What symptoms occur with incidental Phrenic nerve block?

Answer 18

-Occurs almost 100% of the time with ISB
-Usually not clinically significant
-Ipsilateral diaphragm paralysis

Question 19

What patient populations do you definitely avoid the ISB due to risk of phrenic nerve involvement?

Answer 19

Severely respiratory compromised patients, especially restrictive diseases.

Question 20

What symptoms occur with incidental Recurrent Laryngeal nerve block?

Answer 20

-Ipsilateral vocal cord paralysis
-Hoarseness

Question 21

What is Horner’s Syndrome?

Answer 21

Occurs due to block of the ipsilateral sympathetic cervical ganglion

S/Sx:
-Bloodshot conjunctiva
-Miosis
-Ptosis
-Facial Flushing
-Anhydrosis (absence of facial sweating)

Question 22

How do you decrease the risk of infection with ISB?

Answer 22

-Avoid puncture of infected tissue
-Ensure good skin prep

Question 23

How do you decrease the risk of hematoma with ISB?

Answer 23

-Avoid External Jugular vein
-Increased risk with prolonged needling (avoid)
-Hold pressure after inadvertent vascular puncture

Question 24

What occurs with intra-arterial injection with ISB?

Answer 24

Risk for LA toxicity.
-Vertebral, Carotid, Subclavian
-Small volumes 1-3ml can cause almost immediate seizure, systemic LA toxicity
-Aspirate while needling
-Apply pressure for 5 min of arterial puncture occurs

Question 25

What occurs with intra-venous injection with ISB?

Answer 25

Risk for LA toxicity.
-Vertebral, IJ, EJ
-Compression of vessels during needling may hide IV puncture, so no aspiration of blood
-Slower onset of LA toxicity S/Sx

Question 26

How do you prevent LA toxicity?

Answer 26

-Continuous monitoring of ECG, BP, and SpO2 for 30 minutes after high dose blocks
-Have pt report s/sx: metal taste, ringing in ears, circumoral numbness, anxiety
-Frequent aspiration every 3-5 mL
-Slow injection of LA
-Avoid traumatic needling
-Judicious dosing of LA
-Epi marker in high volume blocks
-Have a plan (NYSORA flowchart or ASRA checklist)
-Have 20% Lipid Emulsion in the area where blocks are performed.

Question 27

How can an ISB cause a Total/High Spinal?

Answer 27

Due to injection of LA into cervical neural foramina or dural cuff.
-Subdural space runs continuous with the dural cuff.
-Can inject into the subdural space, and then it’s basically like a spinal. Immediate distress
-S/Sx: Severe hypotension/bradycardia, respiratory insufficiency/arrest, and unconsciousness
-Prevention: Use US, never inject LA when stimulation achieved with stimulator current <0.2 mA

Question 28

How do you treat a Total/High Spinal?

Answer 28

-Early recognition is paramount!!
-Communicate with the pt (They may soon lose consciousness)
-Maintain adequate airway and ventilation
-Supplemental O2 🡪 🡪 🡪 intubation and controlled ventilation
-Support hemodynamics aggressively
-Wide open fluids
-Trendelenburg
-PRESSERS: Ephedrine and Phenylephrine may not be enough. EPInephrine and/or DOPAmine drips may be warranted

Question 29

Which Brachial Plexus Block has the highest incidence of pneumothorax?

Answer 29

Supraclavicular Block (SCB)

Question 30

What are the indications for a Supraclavicular Block (SCB)?

Answer 30

-Entire upper extremity distal to shoulder
-Most reliable block for entire upper extremity
-Includes Ulnar nerve

Question 31

What level of the brachial plexus is being blocked by a Supraclavicular Block (SCB)?

Answer 31

-Distal Trunks
-Proximal Divisions

Question 32

What nerve has to be blocked separately with a Supraclavicular Block (SCB)?

Answer 32

Intercostobrachial nerve.
-Small area of the upper arm, medial, below armpit
-Can be an issue with tourniquet pain
-Run a superficial skin wheal (about 10 ccs) anterior to posterior across the upper part of the arm.

Question 33

What are the absolute contraindications for a Supraclavicular Block (SCB)?

Answer 33

-Patient refusal
-Allergy to local anesthetics
-Local infection at or near the needle insertion site
-Bilateral Blocks: Risk for Bilateral phrenic nerve blockade and Bilateral Pneumothorax

Question 34

What are the relative contraindications for a Supraclavicular Block (SCB)?

Answer 34

-Uncooperative patient
-Severe respiratory compromise
-Coagulopathy or Anticoagulation
-Traumatic nerve injury in the upper extremity or neck
-Preexisting neuro deficits in the distribution of the block
-Previous surgery in the neck that may distort brachial plexus anatomy

Question 35

What are the risks associated with a SCB?

Answer 35

-Pneumothorax (highest likelihood of any BP block)
-Incidental Blockade: Phrenic, Recurrent Laryngeal, and Cervical Sympathetic Ganglion (less likely than with ISB)
-Infection
-Hematoma
-Intravascular injection
-LA toxicity
-Total Spinal Anesthesia

Question 36

What is the relevant anatomy for a SCB?

Answer 36

-Clavicle
-SCM
-1st Rib (Pleural dome)
-Subclavian Artery

Question 37

Stimulation of the Upper trunk should result in what twitching?

Answer 37

Shoulder twitching

Question 38

Stimulation of the Middle trunk should result in what twitching?

Answer 38

Bicep/Tricep/Pectoral

Question 39

Stimulation of the Lower trunk should result in what twitching?

Answer 39

Finger twitching

Question 40

How do you perform a SCB?

Answer 40

Position probe above the clavicle
-View includes subclavian artery, BP, and 1st rib
-Go lateral to medial directly along superior surface of clavicle
-Goal is to achieve lower trunk twitching at 0.3-0.5 mA
-Inject 25-35 mL LA
-Inject LA both above and below plexus to ensure good coverage
-Always be careful of needle movements around partially anesthetized nerves
-Continuous catheter can be placed

Question 41

Describe the nerve stimulator technique for the ISB?

Answer 41

-Insert needle 3-4 cm above clavicle (about C6)
-Perpendicular to skin (Slightly caudal)
-BP usually 1-2 cm deep

Goal:
-0.3 – 0.5mA stimulation of:
Pectorals, Deltoid, Triceps, Biceps, hand, or forearm
-Inject LA while holding needle in place

If unable to elicit twitch withdraw needle to skin and systematically redirect needle Ant/Post, keeping slightly caudal angle

Question 42

Describe the nerve stimulator technique for the SCB?

Answer 42

-Locate the lateral border of the SCM clavicular head
-Palpate plexus 2-3cm lateral to SCM
-Place finger in this groove (↑ difficulty in obese pts)
-Needle initially inserted AP or “plumb bob”
-50mm stimulating block needle
-Systematic redirecting needle more caudally until contact made
-Upper trunk should be encountered first
-Needle is systematically redirected in a more caudal/posterior angle
-Goal is to achieve lower trunk twitching (0.3-0.5mA)
-25-35 ml LA
-Lower trunk = finger twitching