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N931 Advanced Principles > Week 5 Upper Peripheral Nerve Blocks > Flashcards

Week 5 Upper Peripheral Nerve Blocks Flashcards

1
Q

What are the five indications for regional anesthesia?

A 
Primary anesthetic
post-operative pain management
history of severe PONV or risk of MH
Patient is too ill for general anesthesia
physician (surgeon) preference
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2
Q

Benefits of Regional Anesthesia (6)

A 
decreased risk of PONV
decreased postop pain
decreased LOS
increased patient satisfaction
maintained upper airway adn pharyngeal reflexes
increased gastric mobility
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3
Q

Absolute contraindications for regional anesthesia (4)

A

patient refusal
active bleeding in anticoagulated patient
proven allergy to a local anesthetic
local infection at the site of the proposed block

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4
Q

Relative contraindications for regional anesthesia

A

respiratory compromise
uncooperative patient/ neurological disease/psychiatric disease
an anesthetized patient
bleeding diathesis secondary to an anticoagulant or genetic disorder
blood stream infection
pre-existing peripheral neuropathy

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5
Q

Complications of Regional Anesthesia (4)

A

intravascular injection/LAST
direct nerve injury/intraneural injections
vascular injury/hematoma
infection

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6
Q

What region has the highest incidence of LAST?

A

epidural> axillary > interscalene

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7
Q

What is LAST?

A

local anesthetic systemic toxicity

systemic delivery of large quantities of LA via inadvertent intravascular injection

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8
Q

What channels are depressed with LAST?

A

Sodium, potassium and calcium

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9
Q

Neuro and cardiac symptoms of LAST

A

lack of inhibition of excitatory neurons-> seizure

cardiac: decreased contractility, arrhythmias (brady first), vfib most serious

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10
Q

What LA carries the most reported deaths?

A

Bupivacaine

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11
Q

What drugs are less cardiotoxic for LAST?

A

shorter acting drugs

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12
Q

What are clinical signs of LAST?

A 
progressive CNS excitation
agitation
tinnitus
circumoral numbness
blurred vision
metallic taste
muscle twitching
unconsicousness
seizure
cardiac and respiratory arrest
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13
Q

What are safety precautions for LAST?

A 
ultrasound guided regional anesthesia
aspiration before injection
incremental injection
lower doses
test dose
awake/sedated patients
midazolam
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14
Q

Treatment of LAST

A

prompt recognition and diagnosis
airway management priority (seizure suppression, benzo) prevent hypoxia and acidosis
Lipid emulsion therapy
Vasopressors Epi< 1mcg/kg, no vasopressin

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15
Q

What is the dose for lipid emulsion therapy?

A

1.5ml/kg 20% rapidly Q2-3minutes

infusion 0.25ml/kg/min (IDW)

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16
Q

What are the benefits of UGRA vs. traditional landmark technique?

A 
Visualization
improvement of block quality
use of lower doses of local anesthetic
less painful administration
improved patient satisfaction
safer
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17
Q

What can you visualize with the US?

A

anatomic structures
real time needle movements
spread of LA

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18
Q

Define UGRA

A

in-plane/longitudinal preferred allows visualization of entire needle

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19
Q

What is an ART manuever?

A

alignment- sliding
rotation
tilting- maximizing angle of incidence of beam to target structure

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20
Q

Where are the peripheral nerve stimulators placed?

A

negative lead attaches to skin

positive lead attaches to needle

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21
Q

Define peripheral nerve stimulator for regional anesthesia?

A

controlled stimulating pulse of variable amplitude

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22
Q

What is the goal of peripheral nerve stimulator?

A

maintenance of motor stimulation with minimal amplitude

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23
Q

When using the PNS, when do you stop?

A

if motor response seen with <0.2mA

chance of intraneural injection

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24
Q

When do you turn on the stimulator?

A

when the needle has entered the skin

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25
Q

How much LA is enough?

A

most references recommend 20-40mL per block

some authors have demonstrated successful, complete interscalene blocks with as little as 5ml

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26
Q

What does the amount and type of LA depend on?

A

patient factors
procedure
purpose of the block
timing of the procedure

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27
Q

Pre-procedure Checks

A 
verify the correct patient
obtain informed consent
verify the correct procedure
verify the correct extremity
gather all necessary equipment
Place patient on O2/ etCo2 during monitoring (sedation_
obtain baseline VS and monitor during the procedure
administer proper/adequate sedation
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28
Q

Indications of a cervical plexus block

A

carotid endarterectomy
superficial neck surgery
clavicle fractures
lateral surface of ear

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29
Q

Contraindications of cervical plexus block

A

SOB
COPD
HEmi-diaphragm

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30
Q

Describe a cervical plexus block

A

branches of cervical nerve roots C2-C4
provides anesthesia to the anterolateral neck, anterior and retro auricular areas and the anterior chest just inferior to the clavicle

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31
Q

What are the major nerves in the cervical plexus?

A 
transverse cervical nerve
great auricular nerve
lessor occipital nerve
supraclavicular nerve
phrenic nerve?
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32
Q

PEARLS of Cervical plexus

A

visualization of nerves in plexus is not neccessary

since plexus nerves are purely sensory, lower concentration of LA used

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33
Q

Technique of Cervical Plexus

A

patietn position with head turned to non-operative side
transducer placed at midpoint of SCM moved laterally until posterior edge is identified
identify brachial plexus between anterior and middle scalene muscle
cervical plexus located in plane above prevertebral fascia
needle passed lateral to medial, in-plane to area between SCM and prevertebral fascia
following negative aspiration, PF NS for hydro dissection then inject 5-10ml of LA

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34
Q

What needle is used for cervical plexus?

A

20 g 2” needle

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35
Q

Side effects/Complications of cervical plexus?

A

poor needle visualization can result in intrathecal injection due to close proximity of vertebral nerve roots
and potential intravascular injection in vertebral artery

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36
Q

What is the brachial plexus?

A

large network of nerves- neck and axilla and innervate upper extremity
consist of ventral rami of the C5-T1 nerve roots

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37
Q

What innervation runs through the brachial plexus?

A

brachial plexus supplies sensory and motor innervation to the upper extremity

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38
Q

How many roots are in the brachial plexus?

A

five

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39
Q

How many trunks are in the brachial plexus?

A

three

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40
Q

How many divisions are in the brachial plexus

A

six

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41
Q

How many cords are in the brachial plexus?

A

three

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42
Q

How many branches are in the brachial plexus?

A

five

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43
Q

What do the proximal branches innervate?

A

dorsal scapular, phrenic and long thoracic

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44
Q

What do the lateral branches innervate?

A

suprascapular, subclavian, lateral pectoral

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45
Q

What do the medial branches innervate?

A

medial pectoral, medial cutaneous to arm and forearm

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46
Q

What is posterior?

A

upper and lower subscapular, thoracodorsal

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47
Q

C5 brachial plexus dermatomes innervate

A

shoulder abduction

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48
Q

C6 brachial plexus dermatomes innervate

A

elbow flexion

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49
Q

C7 brachial plexus dermatomes innervate

A

elbow extension

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50
Q

C8 brachial plexus dermatomes innervate

A

finger flexion

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51
Q

T1 brachial plexus dermatomes innervate

A

finger abduction/adduction

52
Q

How do evaluate a brachial plexus block?

A

Baseline: push, pull, pinch, pinch

post-procedure allows you to differentiate blockade

53
Q

When you evaluate a brachial plexus block what does push represent?

A

radial nerve

triceps muscle

54
Q

When you evaluate a brachial plexus block what does pull represent?

A

musculocutaneous nerve

biceps muscle

55
Q

When you evaluate a brachial plexus block what does pinch represent?

A

ulnar nerve

median nerve

56
Q

What are the four brachial plexus blocks?

A

interscalene
supraclavicular
infraclavicular
axillary

57
Q

Indications for a interscalene block?

A 
procedures of the shoulder and proximal upper arm
suprascapular nerve (scapula)
58
Q

Where does an interscalene block occur?

A

root level block

59
Q

WHere are the nerve roots C5-C7 found?

A

in the interscalene groover between the anterior and middle scalene muscles

60
Q

Describe the ISB technique

A

supine position with head turned to non-operative side
high frequency linear array transducer placed in the mid-clavicular fossa and moved cephalad
hypoechoic roots located between the ASM and MSM

61
Q

what needle is used for an ISB

A

5cm, B bevel needle

62
Q

How much LA is injected for ISB

A

incremental injection of 5ml up to 20-30ml

63
Q

If using nerve stimulation for ISB, when do you need to withdrawl needle?

A

nerve stimulation is not required, however is used when it occurs at 0.5mA, the needle should be withdrawn slightly

64
Q

What should be performed with the US prior to injection in an ISB?

A

pre-procedure scan with color doppler

limit potential inadvertent injections and identify anatomic variations

65
Q

Side effects/ complications of ISB

A

phrenic blockade occurs 100% of time
stellate ganglion blockade (Horner’s) syndrome is common
LAST
high spinal
injury to the dorsal scapular and long thoracic nerves

66
Q

What are symptoms of horner’s syndrome?

A

ptosis
miosis
anhidrosis

67
Q

Indications for ISB continuous catheter

A

total/hemi shoulder arthroplasty, proximal humerus, distal clavice, rotator cuff

68
Q

Contraindications to ISB continuous catheter

A

contralateral diaphragmatic paralysis, significant OSA/respiratory distress

69
Q

Where is the catheter placed for ISB?

A

near C5-C7 roots between ASM and MSM

70
Q

What supplies are needed for ISB with continuous catheter?

A

1% lidocaine 27g needle

4” echogenic tuoy needle, wire stylet catheter with clamp, PS NS for hydro dissection

71
Q

What position should the catheter be placed for ISB continuous catheter?

A

lateral position, allows for posterior placement away from surgical field

72
Q

When using a nerve stimulator what nerve can be stimulated?

A

dorsal scapular nerve

73
Q

Where is the catheter going in ISB CC?

A

corner pocket between C5 and fascia above

74
Q

What LA is best for postop pain in ISB CC?

A

0.25% marcaine and 0.2% ropi at 6 ml/hr (titrate)

75
Q

What LA is best for surgical pain in ISB CC?

A

0.375%-0.5% marcaine/Ropi

76
Q

When do you d/c infusion and assess with ISB CC?

A

SOB or difficulty swallowing

77
Q

indications for a supraclavicular block?

A

reliable upper extremity block for procedures of the upper arm and hand

78
Q

What levels does a supraclavicular block occur?

A

trunk and division level

79
Q

What level is the brachial plexus most compact?

A

supraclavicular level

80
Q

Describe the SCB technique

A

supine head turned away
transverse image using in-plane needle insertion
trunks/ divisions are found lateral to the pulsating subclavian artery and superior to the first rib
needle is inserted lateral to medial toward the inferior aspect of the plexus where the rib and artery meet (corner pocket)
Following negative aspiration, incremental injections of 5ml is accomplished (30 ml max)

81
Q

What will twitch in a SCB with 0.4-.05mA of stimulation?

A

hand twitch

82
Q

SCB side effects and complications

A

increased risk of phrenic nerve paralysis and stellate ganglion block
pneumothorax is most important complication
because of the proximity of the subclavian artery, there is the possibility for inadvertent arterial puncture (hematoma/LAST)

83
Q

Infraclavicular block is what level block?

A

cord level block

84
Q

Who benefits from a infraclavicular block?

A

alternative to supraclavicular block

patients with COPD or respiratory insufficiency

85
Q

How are the cords labeled?

A

in relation to the axillary artery

86
Q

Indications for a infraclavicular block?

A

elbow forearm and hand

87
Q

Infraclavicular technique

A

patient placed in supine position with head turned to non-operative side
transducers is placed perpendicular to the clavice just medial to the corarcoid plexus
short axis image
cords are arranged around the axillary artery

88
Q

What needles are used in the infraclavicular technique?

A

22gauge 4” stimulating needle inserted in plane, cephalad to caudal

89
Q

Describe the injection process of infraclavicular technique

A

20-30ml of LA around axillary artery
5-10ml in area of lateral cord
10-20 ml in area of posterior cord
U shaped spread of LA around the artery (will cover medial cord)

90
Q

Can you use a low-frequency transducer for infraclavicular block?

A

yes, depends on patients body habitus

91
Q

What block may require additional SQ LA?

A

infraclavicular block

92
Q

During a infraclavicular block if the needle is slide medially what complications may occur?

A

pneumothorax and hemothorax

93
Q

What artery/veins do you need to be aware of with an infraclavicular block?

A

thoraco-acrominal artery and pectoral vein passes between the pectoral muscles

94
Q

Where is the first twitch noted when performing a infraclavicular block?

A

elbow flexion from musculocutaneous nerve

need response in hand (flexion and extension) for anesthesia of hand

95
Q

Complications of an infraclavicular block?

A

poor needle visualization may result in advertent:
pneumothorax/hemothorax
vascular puncture
LAST Event

96
Q

Where does an axillary block occur?

A

directed at the terminal branches of the brachial plexus
radial nerve
ulnar nerve
median nerve

97
Q

Indications of axillary block?

A

procedures below the elbow

98
Q

The axillary technique

A

patient supine with head turned to the non-operative side, arm abducted and rotated externally
high frequency linear array transducer is placed in teh crease formed by the biceps msucle and pectoris major

99
Q

What needle is used for axillary blocks?

A

22g 5cm B bevel needle inserted in-plane cephalad to caudal direction
incremental injection of 20-40ml

100
Q

How can you improve the axillary block?

A

compress veins to decrease the rise of puncture

block the radial nerve first because its deep location

101
Q

Describe the pre-procedural scan for axillary block?

A

slide the transducer distally to appreciate each of the nerves, then follow them proximally to their origin
trace axillary artery towards elbow, the nerve stays adjacent is the median nerve
the nerve that breaks away from artery in axilla is ulnar nerve
radial nerve emerges from behind humerus tangential to it

102
Q

Complications of axillary block

A

not common
increased risk of vascular puncture because needle must be re-directed several times to achieve adequate local anesthetic distribution
paresthesia from multiple needle punctures may result in in neuropathy
multiple veins located around artery- risk of LAST
if tourniquet required, intercostobrachial block must be performed

103
Q

Transarterial technique

A

intentional penetration of axillary artery
aspiration of blood as end point for determining needle in sheath
LA skin wheal raised about the artery, insert needle with aspiration, when no longer able to aspirate blood LA is injected
test dose 3-5ml
observe for 1 minute

104
Q

What is the purpose of nerve blocks at the elbow?

A

rescue for incomplete block or selective to minimize amount fo anesthesia

105
Q

Nerve blocks at the elbow and wrist are

A

sensory blocks, primarily

106
Q

Where are nerve blocks at the wrist and elbow localized to?

A

radial nerve
ulnar nerve
median nerve

107
Q

What are all three nerves of a elbow or wrist block close too?

A

vascular structures or bone

find the contrast

108
Q

Median nerve block at the elbow US technique

A

courses alongside the brachial artery in the upper arm to the elbow
needle inserted in-plane lateral to medial
following negative aspiration inject 4-5ml of LA
additional 2-3 ml can be inejected if circumferential spread is not noted

109
Q

Radial nerve US Technique

A

scan distally along the lateral humerus
identify the nerve as it takes a more anterior course along the humerus
needle inserted in-plane, lateral to medial
following negative aspiration, inject 4-5mL of LA
an additional 2-3 ml may be injected if circumferential spread is not obtained

110
Q

Ulnar nerve block at the elbow US technique

A

scan medially to identify the medial epicondyle
insert between medial condyle of humerus and olecranon process of ulna
scan proximal and distal along the arm to identify where the nerve enters
needle inserted inplane, medial to lateral
following negative aspiration, inject 4-5ml of LA
an additional 2-3ml may be injected if circumferential spread not obtained
risk of nerve entrapment

111
Q

Define Intravenous regional anesthesia

A

block in which local anesthetic is injected into the venous system of an extremity that has been exsanguinated by compression and isolated by a tourniquet
technically safe, simple and rapid means producing surgical anesthesia of the extremity

112
Q

When is IVRA best?

A

procedures <1hour

113
Q

Risk of IVRA

A

LA entering central circulation- emergency equipment needed

114
Q

what are the two mechanisms of IVRA

A

direct- local bathing nerve endings in the tissue

indirect- LA transported to the substance of the nerves via the vasa nervorum

115
Q

Indications of IVRA

A 
brief surgical procedures and manipulations
ganglion cyst excision
carpal tunnel release
dupuytren's contractures
fracture reduction (mostly in peds)
treatment for regional pain syndromes
analgesia
reduce neurogenic inflammation
116
Q

Absolute contraindications for IVRA

A

patient refusal

117
Q

Relative contraindications of IVRA

A 
injuries to the extremity (crush or open)
inability to cannulate peripheral vein
local skin infection or cellulitis
true allergy to LA
pre-existing arteriovenous fistula
sickle cell disease
surgery greater then one hour
118
Q

IVRA procedure

A
  1. place IV in distal vein
  2. apply a double-pneumatic tourniquet on the proximal arm
  3. Elevate the extremity and apply an esmarch bandage
  4. occlude the axillary
  5. inflate the proximal cuff to 250mmHg or 100mmHg above patient’s systolic BP for upper extremity
  6. remove esmarch bandage
  7. inject 30-50ml of 0.5-1% lidocaine
  8. if patient complains of tourniquet pain, inflate distal cuff first then deflate proximal cuff
119
Q

How long does the tourniquet have to be inflated after the injection of LA regardless of surgical procedure?

A

30 minutes

120
Q

After 30 minutes, how does the cuff tourniquet deflate?

A 
cyclical fashion
cuff deflated, then instantly reinflated
watch for complications
wait 1-2 minutes
repeat
121
Q

What complications do you assess for while tourniquet as it cycles?

A

signs of LAST or others

122
Q

Side effects and complications of IVRA

A 
if lower extremity, 100% incidence of LA leakage under the tourniquet (observe for symptoms of last)
damage to radial, median and ulnar nerve
compartment syndrome
arterial thrombosis
death or permanent brain damage
123
Q

Complications of regional

A

LAST
nerve injury
intravascular puncture/injection
death

124
Q

Nerve injury occurs by

A

direct needle trauma
local anesthetic neurotoxicity
pre-existing patient factors
patient’s perception of postop course

125
Q

What are patient factors that lead to nerve injury?

A 
diabetes
pre-existing neurologic disease
smoking
increased BMI
male

N931 Advanced Principles (14 decks)

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