Upper Extremity Nerve Blocks Flashcards
What are the five components that make up the brachial plexus anatomy?
Roots –> Trunks –> Divisions –> Cords –> Nerves
Where are the roots in the brachial plexus?
They come off of the spinal cord itself
What are the three components of the trunks?
Superior
Middle
Inferior
Where are the division in the brachial plexus?
Divisions are underneath the clavicles
What nerve supplies motor and sensory to the scapula in the back of the arm?
Suprascapular nerve (exits C5-6)
What are the three components of the cords?
Lateral, posterior and medial
What three nerves are enveloped in the brachial fascia?
Median nerve
Radial nerve
Ulnar nerve
What nerve roots are encompassed in the median nerve?
C5, 6, 7,8 and T1
What nerve roots are encompassed in the radial nerve?
C5, 6, 7, 8 T1
What nerve roots are encompassed in the ulnar nerve?
C7, 8 T1
What nerve supplies a large portion of the distal arm?
Musculocutaneous nerve
Where is the brachial plexus located?
Runs off the neck between the anterior and middle scalene muscles
What is the importance of the sternocleidomastoid muscle?
Point of clavicular attachment
What structure emerges and crosses the scalene muscle?
The phrenic nerve (bilateral)
What is the primary function of the phrenic nerve?
Primarily motor to diaphragm but does have sensory, can have dull achy pain if hit by needle
What can occur if LA is injected too close to the phrenic nerve?
Blocks nerve conduction resulting in a hemidiaphragm
Where can LA be injected to anesthetize all three nerves of the brachial plexus?
Fascial tube
What muscle does the musculocutaneous nerve innervate?
The corticobrachialis muscle
What part of the hand does the median nerve supply?
Part of the thumb, the index and middle finger and have of the ring finer
What part of the hand does the radial nerve supply?
Supplies the part of the thumb, up the arm and parts of the index and middle finger
What part of the hand does the ulnar nerve supply?
Supplies pinky side of the ring finger and the pinky finger
If the surgeon is operating on the ring finger what two nerves need to be blocked?
The median and the ulnar nerve
If the surgeon is operating on the thumb what two nerves need to be blocked?
The median and radial nerve
What are the three approaches to a brachial plexus block?
Axillary
Interscalene
Supraclavicular
What is the most common approach to a brachial plexus block?
Axillary Approach due to minimal number of complications
What surgeries is a brachial plexus indicated?
Surgery below the elbow and hand, good for surgeries on forearm and wrist
How must the arms be positioned to perform an axillary approach to a brachial plexus block?
Arm must be abducted
If a tourniquet is going to be used and a brachial plexus block is planned what additional nerves will need to be blocked?
Intercostobrachial and Medial cutaneous nerves must be blocked separately
Why is it important to make sure that the arm is not abducted greater than 90 degrees in an axillary approach to a brachial plexus block?
If it is abducted greater than 90 degrees the head of the humerus pinches off the fascial sheath and prevents the spread of LA
What is the landmark in an axillary approach to a brachial plexus block?
Palpate the axillary artery, straddle between the index and middle finger and inject skin wheel tangential across artery
Typically how much should the needle be inserted to enter the brachial plexus?
Usually 1-2cm
At what amplitude range is said to be at the nerve plexus?
0.2-0.4mAmp
What volume is required for a axillary approach for a brachial plexus block?
40mL
How often should the provider aspirate and inject LA?
Every 3-5mL
What reaction is seen with stimulation of the median nerve?
Forms a fist and flexes forward toward the wrist
What reaction is seen with stimulation of the radial nerve?
The wrist extends and the hand is in a supinated position
What reaction is seen with stimulation of the ulnar nerve?
The pinky and ring fingers curl towards the thumb the hand makes a twisting motion
What might be the problem if you being injecting LA and the patient begins to scream in pain?
May be injecting into the nerve
What should the provider do if arterial blood is aspirated when performing an axillary approach to a brachial plexus block?
Can advance the needle to the other side of the artery, and ensure you can’t aspirate blood, inject LA behind the artery move out of ensure you are not in the artery and inject the rest
What has occurred if the provider has aspirated venous blood during an axillary approach to a brachial plexus block?
The provider is outside of the sheath
How can nerve blockade be assessed after an axillary approach to a brachial plexus block?
Take the persons hand like you are arm wrestling
Push against hand if they aren’t able to = radial nerve blocked
Pull- have patient pull toward them, if not musculocutaneous nerve blocked
Pinch the pinky = ulnar nerve block
Pinch the middle finger = median nerve blocked
If the musculocutaneous nerve is not blocked with an axillary approach how can it be rescued and blocked?
Inject LA into the belly of the coricobrachiallis muscle
Why might it be difficult to block the musculocutaneous nerve in an axillary approach?
It exits the sheath high, above the humeral head
How do you block the intercostobrachial nerve and the medial brachial cutaneous nerve?
When finishing in the plexus, back the needle into the subcutaneous tissue and redirect down towards the posterior side of the axilla
Inject a skin wheal with 5-7mL of LA
Why might bicarbonate be injected with a LA?
Speeds onset and enhances duration
What anesthetic will HCO3 precipitate?
Bupivicaine
How much HCO3 can be added to LA that isn’t bupivicaine?
1mL per 10mL of LA
How much HCO3 can be added to bupivicaine?
0.1mL to LA
How many anesthetic and analgesic hours can a provider get with 1.5% Mepicacaine with epi and HCO3?
Anesthesia 2.5-4hrs
Analgesia 3-6hrs
How many anesthetic and analgesic hours can a provider get with 2% Lidocaine with epi and HCO3?
Anesthetisa: 3-6hrs
Analgesia: 5-8hrs
How many anesthetic and analgesic hours can a provider get with 0.5% Ropivicaine with epi and HCO3?
Anesthesia: 6-8hrs
Analgesia: 8-12hrs
What are some advantages to the interscalene approach to a brachial plexus block?
Can use for shoulder surgery
Risk of pneumothorax is small
What is a disadvantage to the interscalene approach to a brachial plexus block?
The ulnar nerve may be spared and not blocked
What are some complication of the interscalene approach to a brachial plexus block?
Unintentional epidural or spinal
Puncture of vertebral artery
Phrenic nerve block
Why is the head turned to the side in an interscalene approach to a brachial plexus block?
In order to identify the clavicular head and the sternal head of the sternocleidomastoid muscle
How is the brachial plexus located for an inter scalene approach?
Come across laterally from C6 (where cricoid cartilage is) intersects with EJ where scalene groove is located
If we accidentally hit the subclavian artery where is the brachial plexus in relation to where we are?
Posterior to the subclavian artery
How can we aspirate CSF in an attempt to block the brachial plexus with an interscalene approach?
If we go too far up we can puncture the dura
At what angle should an interscalene approach be done?
About a 45 degree angle if go in straight runs risk of puncturing the vertebral artery
What is the goal stimulation of the brachial plexus?
0.2-0.4mAmp
What muscle may twitch if the provider is successfully in the brachial plexus with an interscalene approach?
Pectoralis, Deltoid, Triceps, Biceps and any twitch of hand or forearm
How many milliliters of LA should be injected for an interscalene approach?
35-40mL
At what point should the provider not advance the needle any more with an interscalene approach?
No more than 2.5cm to avoid the risk of complications
Is it normal for a patient to experience a hoarse voice, mild ipsilateral ptosis and nasal congestion after an interscalene approach?
Yes, Horners Syndrome from LA diffusing out and anesthetizing the stellate ganglion
What patients should an interscalene approach be avoided in?
Asthma and COPD due to paralysis of the phrenic nerve
What types of surgeries is an anterscalele brachial plexus block indicated in?
Shoulder, arm and elbow surgery
What are some advantages to the supraclavicular approach to a brachial plexus block?
Arm can be in any position
Brachial plexus is very compact here
What is a disadvantages to the supraclavicular approach to a brachial plexus block?
Pneumothorax is a risk
How is the brachial plexus located in the supraclavicular approach?
Same at interscalene, palpate down the neck follow groove to supraclavicular area
Where should the needle be inserted for a supraclavicular approach?
Between the inferior and middle scalene muscles
How does the provider know if they have gone too far with a supraclavicular approach?
Will run in to first rib
What nerve is prone to stimulation with a supraclavicular approach?
Suprascapular nerve
If the supra scapular nerve is stimulated where should the provider redirect the needle?
The provider is on the posterior side of the sheath need to redirect anteriorly
What reaction will the provider see if the suprascapular nerve is stimulated?
The scapula will wing, can be deceptive
How much volume is required for a supraclavicular approach?
20-25mL because the plexus is very compact in this area
What areas does the supraclavicular approach anesthetize?
Covers everything except for the inferior part of the upper arm, have to block the intercostal brachial and medial cutaneous nerves
What types of surgeries is the supraclavicular approach indicated for?
Shoulder, arm and elbow surgery
