Upper Peripheral Nerve Blocks Flashcards
What are the 3 ways to ID a nerve
inducing a parasthesia, US, nerve stimulator
What are the advantages of regional anesthesia?
induced sympathectomy - reduced blood loss and improved post op perfusion
reduced N/V
pre-procedure analgesia
During a brachial plexus block, what area of the upper extremity is generally not going to be blocked
the posterior shoulder
What are the 5 terminal nerves
musculocutaneous, radial, axillary, ulnar, median
Describe the flow of electricity through the nerve stimulator
current flows from Black wire (+) to Red wire (-)
black wire should be distal and red wire should be more proximal
What is the benefit of an insulated needle?
the electricity will only come out the bevel instead of along the whole shaft
B bevel needle
has a short tip and a greater angle
When would you use an interscalene block?
surgery of the shoulder or upper arm, clavicle procedures, procedures proximal to the elbow
What is often “spared” during an interscalene block? How will you know?
ulnar nerve - little finger and ring finger won’t be blocked, you’ll still be able to spread fingers and pinch fingers
What are the landmarks to interscalene blocks?
supine with head turned to opposite side, palpate posterior border of SCM at C6, roll fingers posteriorly to find groove between middle and anterior scalene muscles
What are the absolute contraindications to a interscalene block?
phrenic nerve palsy
contralateral RLN palsy
*don’t want to block both sides and cause resp. failure
How should the needle be inserted for an interscalene block?
posteriorly and slightly caudad.
How much volume is injected for an interscalene block?
20-30 mL
How can you evaluate an interscalene block?
push & pull with arm, open and close fist, test sensory loss with an alcohol pad and tongue depressor.
What are the major complications of an interscalene block?
intravascular injection, Horner’s syndrome, pneumothorax, RLN block, phrenic nerve block, injection to subarachnoid space
How common are phrenic nerve blocks? How should this influence your practice?
80-100% will get a phrenic nerve block. Warn the patient that it might feel difficult to take a deep breath.
When would you block the cervical plexus?
CEA procedures. unilateral neck surgeries.
When would you do a supraclavicular approach?
any surgery along any level of the arm because it blocks the TRUNKS of the plexus.
What are the contraindications to a supraclavicular block?
contralateral phrenic/RLN paralysis or contralateral pneumothorax
What are the major risks of performing a supraclavicular block?
highest risk of pneumothorax, hitting dorsal scapular artery or IJ
What are the landmarks for a suprclavicular approach?
lateral border of the SCM near the clavicle, find grooves between the scalene muscles, then inject with needle directed caudally (NOT MEDIAL)
What is the first thing you should do once you have the needle inserted during a suprclavicular block?
attempt to elicit a motor response –> the more distal the response the better the block
What is the most important part of the your technique during injection?
ASPIRATE and then inject 5 mL at a time. Repeat.
When would you perform an infraclavicular block?
for surgeries below the elbow, the hand, the forearm
What are the landmarks for the infraclavicular approach?
the coracoid process and the medial clavicular head. Insert needle at 45 degrees midway between these 2 points. Advance the needle parallely
What type of twitch are you looking for with an infraclavicular block?
median, ulnar or radial twitching
Which type of block is good for continuous catheters?
infraclavicular blocks
What is the first type of twitch you’ll see with an infraclavicular block? What should you do?
pectoral twitch - continue to advance your needle
What are the indications for an axillary block?
surgery below the elbow
must be able to abduct the arm and bend at the elbow 90 degrees.
If you’re attempting an axillary block on a very muscular patient, what is important to consider?
Their musculature may impede axillary artery flow when they abduct and bend the arm so you may need to support it with positioners when placing the block
What are the injection volumes for an axillary block?
10 mL above and below the axillary artery. 5 mL for the musculocutaneous nerve.
What are the absolute contraindications for an axillary block?
lymphangitis
Where is the median nerve in relation to the axillary artery?
superior/anterior
Where is the radial nerve in relation to the axillary artery?
posterior
Where is the ulnar nerve in relation to the axillary artery?
inferior
Where is the musculocutaneous nerve located in relation to the axillary artery?
Outside of the sheath altogether. Located more laterally in the arm.
What is the major landmark you’re looking for during an axillary block?
the axillary artery pulse
What is the transarterial technique?
insert clear through the axillary artery, then inject to get the radial nerve. Pull back and aspirate to make sure you’re no longer in the artery and then inject to block the median and ulnar nerves.
Why is the transarterial approach note used as frequently?
Because there is a large risk for hematomas and for intravascular infiltration of the anesthetic
What is the nerve stimulator technique for axillary artery?
insert either superiorly or inferiorly to the axillary artery, start stimulator at 1.0 mAmp. Note the twitch in hand, drop to 0.5 mAmp or lower until twitch disappears, aspirate and then inject
What is the injection volume for an axillary block?
30 mL, 5mL at a time
What nerve/muscle is generally “spared” during an axillary block? What should you do?
musculocutaneous nerve and coracobrachialis muscle –> you can block the belly of the coracobrachialis muscle separately.
What are the major complications of the axillary block?
hematoma, intravascular injection, infection (dirty area)
When is a “touch-up” block warranted?
If you’ve missed a specific nerve in one of the other blocks
When would you do a Bier block?
intra-op procedures below the elbow
How can you perform a Bier block?
place an IV in the same arm. Exsanguinate the arm and place a double tourniquet on the upper arm. Inflate the upper portion of the tourniquet first. Inject 40 mL of anesthetic. When the patient complains of tourniquet pain, deflate upper cuff and inflate the lower cuff.
How long will a Bier block work for?
30-60 minutes per cuff (upper and lower) for a procedure lasting <120 min.
What is the main disadvantage of a Bier block?
local toxicity
What area of the brachial plexus are you blocking during an interscalene block?
roots
What is the most distal block for the musculocutaneous nerve?
infraclavicular block - b/c the nerve leaves the fascial sheath at the level of the coracoid process
