Peripheral Nerve Blocks Part 2 Flashcards
What does the cervical plexus innervate?
sensory- scalp, neck, upper shoulder
motor- muscles of neck, thoracic cavity, skin
What is one of the larger branches of the cervical plexus?
phrenic nerve (C3-5)
Where does the cervical plexus originate from?
ventral rami of C1-C5
What are the external landmarks for a cervical plexus block?
mastoid process, SCM, C6 transverse process
How much LA volume do you use for a cervical plexus block?
15-20 mL
Describe the 2 different methods for a cervical plexus block
deep- paravertebral block of C2-4 spinal nerve roots as they emerge from foramina
superficial: subQ block of distinct nerves of anterolateral neck (favorable due to less complications)
Describe how to perform a superficial cervical plexus block
needle inserted along posterior border of SCM, 3 injections of 5 mL of LA injected behind posterior border of SCM subQ, perpendicularly, cephalad, and caudad
How long is the onset for a superficial cervical plexus block?
10-15 minutes
What can you do to supplement a superficial plexus block in order to prevent pain from a surgical skin retractor on the medial aspect of the neck?
field block (subQ midline injection of LA extending from thyroid cartilage distally to suprasternal notch)
Describe how to perform a deep cervical plexus block
with patient supine/semi-sitting, infiltrate LA subQ along line estimating position of transverse process (c6), advance needle slowly until transverse process contacted, withdraw needle 1 mm and inject 4-5 mL of LA after negative aspiration (repeat at consecutive levels)
What roots form the brachial plexus?
C5-C8 (sometimes C4-T1)
What comes after the brachial plexus roots?
Trunks (upper, middle, lower)
What comes after the brachial plexus trunks?
divisions (anterior or posterior)
What comes after the brachial plexus divisions?
cords (lateral, medial,posterior)
What comes after the brachial plexus cords?
major terminal branches (musculocutaneous, axillary, median, radial, ulnar)
Mnemonic for remembering the major terminal branches of the brachial plexus
“most alcoholics must really urinate”
What are indications for interscalene block?
shoulder, arm, elbow surgery (NOT hand)
What are the landmarks for an interscalene block?
clavicular head of SCM, clavicle, EJV
What are desired responses to nerve stimulation for an interscalene bloc?
twitch of pectoralis, deltoid, arm, forearm, hand
What is the volume of LA used for an interscalene block?
10-20 mL
Describe how to perform an interscalene block
infiltrate 1-3 mL of LA subQ at needle site, press fingers against anterior and middle scalene muscles to shorten distance, insert needle 3-4 cm above clavicle (never orient cephalad), inject around plexus
Indications for supraclavicular block
upper extremity surgery (arm, elbow, forearm, wrist, hand)
landmarks for supraclavicular block
clavicular head of SCM
How much LA volume is used for a supraclavicular block?
25-35 mL
What US anatomy do you look for during a supraclavicular block?
subclavian artery, first rib (plexus is lateral to SA)
What are some risks when doing a supraclavicular block?
pneumo, IV injection, intraneural injection, infection, hematoma, phrenic nerve blockade, unintentional neuraxial spread (airway emergency)
What is the distribution of blockade with a supraclavicular block?
dermatomes C5-T1 (entire upper extremity distal to shoulder including elbow, forearm, and hand)
Describe how to perform a supraclavicular block
with pt semi-sitting and head turned away, supinate arm, palpate lateral insertion of SCM on the clavicle and insert needle immediately cephalad to palpating finger, inject after negative aspiration in proximity of lower trunk
Can you do a bilateral supraclavicular block?
no- risk for respiratory compromise secondary to pneumo or phrenic nerve block
Indications for infraclavicular block
elbow, forearm, and hand surgery
Landmarks for infraclavicular block
medial clavicular head, coracoid process
Desired response to nerve stimulation for infraclavicular block
hand twitch
Volume of LA for infraclavicular block
25-35 mL
Describe how to perform an infraclavicular block
pt supine with head away, have arm abducted and flexed at the elbow, infiltrate needle site insertion and deeper into pectoralis muscle, insert needle at 45 degrees and advance parallel to line connecting medial clavicular head with coracoid process, inject around axillary to distribute LA around LC, PC, and MC
Indications for axillary block
forearm and hand surgery
Landmark for axillary block
axillary pulse, coracobrachialis muscle, pectoralis major
Volume of LA for axillary block
20-30 mL
Describe how to perform an axillary block
pt supine with head facing away, arm abducted to form 90 angle, ID axillary pulse and fix between index and middle finger, infiltrate LA at insertion site, inject 10-15 mL after negative aspiration around plexus, withdrawn needle and reinsert above artery and inject around 5-10 mL around musculocutaneous? nerve
Onset of axillary block
15-20 minutes
What nerves does a PECS 1 block target?
lateral and medial pectoral nerves (anesthesia to pectoralis major)
What nerves does a PECS 2 block target?
intercostal nerves (T2-6) and long thoracic nerves (anesthesia to skin of anterolateral chest, axilla, medial aspect of upper arm, serratus anterior muscle)
Transducer positioning for PECS 1 and 2 block
patient supine or semirecumbent with head turned away, arm abducted to 90 degrees, place transducer in parasagittal plane just inferior to clavicle and medial to coracoid process, ID axillary artery below pec major and minor, locate 2nd-4th ribs, rotate transducer 45 degrees and slide laterally to axilla
Describe PECS II block injection
insert block needle 1-2 cm medial to transducer until tip within fascial plane between pec minor and serratus anterior muscles, inject 1-2 mL after negative aspiration to confirm location, then administer 3-5 mL increment doses up to 20 mL
Describe PECS I block injection
needle tip should be in fascial plane between pec major and minor- confirm placement with 1-2 mL before injecting 3-5 mL increments up to 10 mL
How can you avoid causing a pneumo with a PECS block?
aim needle towards 4th rib so it acts as a backstop
