Peripheral Nerve Blocks Flashcards
1
Q
What are some benefits of regional anesthesia?
A
- minimal physiologic changes
- controlling own airway/reflexes
- postoperative analgesia
- being awake or sedate as the patient desires
- nausea rare
- no urinary retention
- potentially no PACU stay
2
Q
What are the two primary blocks for lower extremities?
A
sciatic and lumbar plexus
3
Q
What are the two approaches for a sciatic block?
A
posterior and anterior
4
Q
What are the two approaches for a lumbar plexus block?
A
- posterior (psoas compartment block) - winnie
- anterior (3 in 1, fascia iliaca)
5
Q
What are the 3 nerves that we are blocking with a “3 in 1” lumbar plexus block?
A
Lateral femoral nerve
Femoral nerve
Obturator nerve
6
Q
Where does the sciatic nerve exit?
A
posteriorly behind the iliac crest in the sciatch notch
7
Q
What nerves are apart of the lumbar plexus?
A
L2, 3, 4, 5
8
Q
What lumbar nerves are apart of the lateral femoral nerve?
A
L2-3
9
Q
What lumbar nerves are apart of the femoral nerve?
A
L2-3-4
10
Q
What nerve branches off of the femoral nerve?
A
saphenous nerve
11
Q
What lumbar nerves are apart of the obturator nerve?
A
L2-3-4
12
Q
What spinal nerves are apart of the sacral plexus?
A
L4-5; S1-2-3
13
Q
What two nerves come off of the sciatic nerve?
A
Peroneal and tibial
14
Q
How do you do the posterior approach to the lumbar plexus block?
A
patient lies on side with hips in line with shoulders, find intercrestal line on back which finds L4, palpate PSIS and compare it to spine midline above buttocks, imagine line going up spine from butt crack and draw line 4 cm up from PSIS, that’s insertion point
15
Q
How do you insertion your needle for a lumbar plexus block posterior approach?
A
insert needle perpendicular to all planes of the patient, NOT perpendicular to bed
16
Q
What motor response do you look for when using nerve stimulator for a lumbar plexus block?
A
quadriceps contraction with symmetrical movement of the patella, patella should be “dancing around”
17
Q
How much local anesthetic do you inject for a posterior lumbar plexus block?
A
25-35 mL
18
Q
How long will it take for full-sensory motor anesthesia of a posterior lumbar plexus block?
A
up to 30 minutes
19
Q
With what type of surgery would a posterior lumbar plexus block be ideal?
A
any type of knee surgery
20
Q
What 3 nerves are you anesthetizing with an anterior lumbar plexus block?
A
lateral femoral cutaneous nerve
femoral nerve
obturator nerve
21
Q
What sensation or motor does the lateral femoral cutaneous nerve provide?
A
sensation only
22
Q
What sensation or motor does the femoral nerve provide?
A
mixed motor/sensory
separate fascial wrapping form femoral A/V
23
Q
What motor or sensation does the obturator nerve provide?
A
mixed motor/sensory
24
Q
What anatomical structures will you find from lateral position of iliac crest to navel for an anterior lumbar plexus block?
A
N (nerve) A (artery) V (vein) E (empty space) L (ligament)
25
Where do you insert the needle for an anterior lumbar plexus block?
just below inguinal ligament, 1-1.5 cm lateral to femoral artery, directed cephalad at about 60 degrees from skin
26
What motor response do you look for with an anterior lumbar plexus block?
want to see quadriceps contract with symmetrical movement of patella at 0.5-1 mA
27
How much local anesthetic do you want for a lumbar plexus anterior block
>20 mL (at least 20 mL needed to reach all 3 nerves)
28
What should you do after injecting local anesthetic for an anterior lumbar plexus block?
massage LA cephalad so that it is distributed around all 3 nerves
29
What is important about the obturator component for a lumbar plexus block?
motor component of obturator allows you to pull your knees together ("Date block")
30
What happens if the patient can pull their knees together after a lumbar plexus block?
block is ineffective and did not get the obturator nerve
31
What if you get no response from anterior apporach to lumbar plexus block?
redirect needle by 15 degrees in lateral direction, if still no response then move insertion point 0.5 cm more lateral
32
What is a sartorious contraction?
contractions of thigh arising from ASIS suggests stimulation of anterior branch of femoral nerve, won't get block if inject there because directly stimulating muscle itself, redirect needle by 15 degrees in lateral direction and advance needle 1-2 mm further
33
What happens if you aspirate arterial blood during an anterior lumbar plexus block?
needle is too far medial, move insertion point 1 cm more lateral
34
What is a fascia iliaca anterior lumbar plexus approach?
blind technique with no nerve stimulator or ultrasound
35
How do you do a fascia iliaca anterior lumbar plexus technique?
find ASIS and pubic tubercle, connect those two with a line, mark junction of 1/3rd and medial 2/3rd and drop down 2 cm and that is insertion point
36
How do you insert the needle for a fascia iliac block?
Needle inserted slightly toward patient's head, 1-2 cm inferior to line from ASIS and pubic tubercle, needle to feel pops of fascia planes as you advance, 2 layers (fascia lata then fascia iliaca), once feel 2 pops can inject LA
37
What motor response do you look for with a fascia iliaca block?
None
38
How much LA do you inject with a fascia iliaca block?
30-40 mL
39
Where do the tibial and peroneal nerve separate from the sciatic nerve?
at the knee
40
What is the classic labat position approach for the sciatic nerve?
pt lies in lateral position with extremity exposed so you can see the foot, find PSIS then move laterally to find the greater trochanter (hip bone), connect the two with a line, at the midpoint of that line draw perpendicular line caudad about 4 cm, that's the insertion site
41
What is the initial motor response for posterior sciatic block?
direct stimulation of gluteus maximus
42
What is a piriformis contraction?
more subtle contraction like a ripple under the skin of hip going t, distinct from gluteal contraction, may become evident by reduction of current during posterior sciatic block,
43
What motor response do you see with tibial stimulation during a sciatic block?
plantar flexion of foot and inversion
44
What motor response do you see with peroneal stimulatlion during a sciatic block?
dorsiflexion and eversion
45
What is the relation of the piriformis muscle to the sciatic nerve?
piriformis msucle goes from sacrum to greater trochanter and sciatic nerve exits just below piriformis muscle, although people can be anatomically different with sciatic muscle going above piriformis muscle or through piriformis muscle, these people tend to have more sciatic pain long term
46
What tissues do you traverse doing a posterior sciatic block and how do you know you are getting close to the sciatic nerve?
transverse skin and subcutaneous tissue, gluteal muscles that overlay the piriformis, when you see piriformis muscle stimulation by hip pulling toward the sacrum, you should begin to see sciatic stimulation
47
What happens if you get no response if doing posterior sciatic block?
redirect needle by 15 degree increments and if no piriformis response is still seen, adjust insertion point by 1 cm back along perpendicular line
48
Is contraction of toes ideal during a posterior sciatic block?
yes, if not contraction of Achilles' tendon is acceptable and if absence of either or above responses then hamstring contraction is sought
49
What happens if you have persistent hamstring contraction in absence of other motor contractions during posterior sciatic block?
redirect needle more laterally
50
What is happening when patient c/o electric shocks down half of their penis/vagina during posterior sciatic block?
stimulation of pudendal nerve which lies medial to sciatic, redirect your needle more laterally
51
What is the approach/technique for an anterior sciatic block?
first make sure patella and toes are facing ceiling (don't want any rotation that can impede ability to get sciatic nerve). find landmarks (ASIS and pubic tubercle), connect the two with a line and divide it into thirds, use medial third, draw perpendicular line caudad, then draw line through greater trochanter parallel to line connecting ASIS and pubic tubercle, intersection of parallel trochanter line and perpendicular line is insertion point
52
How do you insert your needle for an anterior sciatic block?
insertion needle perpendicular to all planes and go 8-10 cm deep (need long needle), will often hit bone or trochanter and if do redirect needle more medially because sciatic is just on the other side of the femur
53
What if you have no motor response doing an anterior sciatic block and you have already redirected the needle more medially?
attempt to minimize obstruction by either internally or externally rotating the leg prior to further advancement of needle
54
How long does it take for the onset of an anterior sciatic nerve block?
up to 30 minutes for full sensory/motor anesthetic
55
How much LA do you use for a sciatic block from any approach?
15-20 mL
56
What should you keep in mind if doing a scaitic block combined with lumbar plexus?
LAST, giving anywhere from 25-40 mL for lumbar plexus and 15-20 for sciatic
57
Can you combine an anterior sciatic with anterior lumbar plexus?
Yes, patient can stay in same position and gets total anesthesia of that extremity
58
If the patient is anticoagulated, can you do sciatic or lumbar plexus block?
follow ASRA guidelines, can develop retroperitoneal hematoma from lumbar plexus block
59
What muscles does the lumbar plexus nerve supply?
anterior and medial thigh
60
What muscles are innervated by the sacral plexus nerve?
buttocks, posterior thigh muscles, and all muscles below the knee
61
The lumbar plexus is formed within which muscle?
psoas
62
What is the classic approach to a popliteal fossa block>
posterior approach
63
What landmarks are identified for a posterior popliteal fossa block?
have patient flex knee joint then identify the popliteal fossa crease, tendon of semitendinousus muscle, and tendon of biceps femoris (make rectangle)
64
Where is the insertion site for posterior popliteal fossa block?
7 cm above posterior fossa crease inbetween semitendinousus muscle and tendon of biceps femoris
65
What is your needle orientation for posterior fossa block?
perpendicular to all planes
66
What is the approach for a lateral popliteal fossa block?
patient lies supine and prop leg up on a pillow
67
What landmarks do you use for a lateral popliteal fossa block?
find lateral femoral epicondyle, and space between vastus lateralis muscle and biceps formis
68
Where is the needle insertion site for a lateral popliteal fossa block?
7 cm caudad to lateral femoral epicondyle and inbetween vastus lateralis muscle and biceps formis muscle
69
How should you insert your needle for a lateral popliteal fossa block?
advance needle perpendicular until you hit the femur, then back the needle out and redirect at a 45 degree angle and then slowly advance
70
What is happening and what do you do if you have local twitch of biceps femoris muscle during a popliteal fossa block?
direct stimulation of the biceps femoris muscle, needle too lateral and needs to be withdrawn and redirected medially 5-10 degrees
71
What is happening and what do you do if you have local twitch of the semitendosus or semimembranosus muscle during a popliteal fossa block?
direct stimulation of the semitendinosus or semimembranosus muscle, needle too medial and needs to be withdrawn and redirected laterally 5-10 degrees
72
What is happening and what do you do if you have twitch of the calf muscles without foot or toe movement during a popliteal fossa block?
stimulation of the muscular branches of the sciatic nerve, disregard and continue advancing the needle until foot or toe twitches are obtained
73
What is happening and what do you do if you have blood in the syringe during a popliteal fossa block?
indicates placement into the popliteal artery or vein, needle is too medial and needs to be withdrawn and redirected more laterally
74
What is happening and what do you do if you hit bone during a popliteal fossa block?
needle hit femur, too deep of insertion so withdraw slowly and look for foot twitch
75
What is a saphenous block often combined with to allow complete anesthesia of lower leg?
sciatic and popliteal fossa block
76
What does the saphenous nerve supply?
sensory to skin on the medial side of the knee from calf down to ankle
77
What landmarks do you find for a saphenous block?
locate tibia
78
What is the technique for doing saphenous block?
local tibia and inject ring of LA starting at medial surface of tibial condyle ending at dorsomedial aspect of upper calf
79
How much LA do you inject for a saphenous block?
5-10 mL
80
What are the 5 nerves you are anesthetizing for an ankle block?
```
saphenous nerve
superficial peroneal nerve
deep peroneal nerve
posterior tibial nerve
sural nerve
```
81
What is the technique for a saphenous block for the ankle?
inject 5-6 mL of LA subcutaneously between lateral malleolus and Achilles tendon (nerve is very superficial)
82
What is the technique to cover the superficial peroneal nerve for an ankle block?
insert needle at tibial ridge and extend laterally toward lateral malleolus and injection subcutaneous wheal of 5-10 mL of LA
83
What is the technique to cover the deep peroneal nerve for an ankle block?
put finger in groove just lateral to extensor hallucis longus, insert needle and advance until contact with bone, withdraw 1-2 mm and inject 2-3 mL LA, can "fan" each side of the artery with additional 2-3 mL LA
84
What is the technique to cover the posterior tibial nerve for an ankle block?
insert in groove behind medial malleolus until contact with bone and then withdraw 1-2 mm, nerve is deep to superficial fascia, inject 3-5 mL LA
85
What is the technique to cover the sural nerve for an ankle block?
insert at lateral malleolus and infiltrate towards Achilles tendon, make superficial "skin wheal" of 5-6 mL
86
Do you have to use pneumatic tourniquet with an ankle block?
No, but if surgeon wants one then may want to do different type of block like popliteal fossa or lumbar plexus and sciatic, because tourniquet pain will be unmanageable. Can use esmarch compression bandage in place of a tourniquet
87
What is the onset of anesthesia with a Bier block?
within 5 minutes
88
Why is the duration of a Bier block limited?
tourniquet time because it gets uncomfortable for the patient
89
What is the procedure time for a Bier block?
90-120 minutes
90
What is important to remember at Bier blocks and your anesthesia?
once tourniquet is released anesthesia is minimal, if hemostasis is required with tourniquet deflated then select another technique
91
What is the technique for a Bier block?
Have patient lie supine, give narcotics/sedatives prn, place stockinet or cotton webril under double tourniquet, Place 22 G or smaller in distal hand as possible, elevate extremity to enhance venous drainage and use Esmarch elastic bandage to exsanguinate venous blood from extremity
92
When inflating the tourniquet for a Bier block, do you inflate the proximal or distal cuff first?
distal and then proximal, then deflate distal
93
How much do you inflate the tourniquet for a Bier block in the arm?
50-100 mmHg above systolic, max is 300 mm Hg
94
How much do you inflate the tourniquet for a Bier block in the leg?
50-100 mmHg above systolic, max 400 mmHg
95
What does it mean to check for bounce with a Bier block?
when squeezing cuff, should see pressure change, use this method to double check that the right cuff is inflated
96
Is it normal for an extremity with a Bier block to be pale and mottled in appearance?
yes
97
What LA do you use for a Bier block?
0.5% Lidocaine that's preservative free
98
Do you use epi with Bier blocks?
NO
99
How much 0.5% lidocaine do you inject for a Bier block?
30-50 mL
100
What does loss of spatial orientation mean during a Bier block?
depending on what position the patient's arm is in when it goes to sleep, they patient will remember their arm being in that position For example, if their arm was up in the air when it was anesthetized and being prepped and draped, they think it is will in that position even though it may be lying on the armboard
101
Who typically removes the IV catheter from operative extremity after you have done your Bier block?
person prepping the site because they can occlude the site and hold pressure where they continue prepping
102
When does tourniquet pain usually start with a Bier block?
30-45 minutes into procedure
103
What can you do to reduce tourniquet pain during a Bier block?
inflate distal cuff then release proximal, make sure to do in that order so patient does not get bolus of LA
104
How long must the tourniquet be up after injecting LA for a Bier block?
>20-30 minutes
105
If you have a tourniquet time of 20-40 minutes and the surgeon is done, what should you do?
release tourniquet briefly then immediately reinflate, observe patient 1 minute and question regarding signs of LAST, repeat process and if no signs of toxicity, deflate and remove tourniquet
106
If the tourniquet was up longer than 40 mintues and the surgeon is done, what should you do?
deflate slowly and observe for signs of toxicity
107
What is a critical complication of Bier blocks?
premature release of LA into systemic circulation, often associated with tourniquet failure, toxicity can progress rapidly into convulsions and apnea, quickly isolate the extremity and support ventilation/circulation
108
What are other complications of Bier blocks beside LAST?
hematoma, engorgement of the extremity, ecchymoses and subcutaneous hemorrhage
109
What processes are involved in the stress response to surgery?
- increased catabolic hormones (cortisol and catechols)
- decreased anabolic hormones (human growth hormone and testosterone)
- marked increase in metabolic rate***
- marked increase in conversion of amino acids to glucose through liver gluconeogenesis
- rapid skeletal muscle breakdown with amino acid use as an energy source
- abnormal nutrient channeling
- lack of ketosis, indicating that fat is not the major calorie source
- unresponsiveness of catabolism to nutrient intake
- inflammatory mediator-induced catabolism (oxidant and cytokine-induced catabolism)
- muscle cachexia from injury or illness
110
How long can the resting metabolic rate be increased after surgery?
Can be as long as 50 days, especially after major burn or major trauma or surgery with critical illness
111
What is regional anesthesia?
loss of sensation in a region of the body produced by application of an anesthetic agent to all the nerves supplying that region without loss of consciousness
112
What is conduction anesthesia?
anesthesia of an area supplied by a specific nerve; produced by an anesthetic agent applied to the nerve
113
What is required for successful regional anesthesia?
knowledge of anatomy
surgeon
cooperative patient
surgical procedure
114
Why does regional anesthesia depend on the surgeon?
they may think it takes too long to do block, history with inadequate or poor blocks, dissatisfied patients
115
Why can regional anesthesia not be used in certain patients?
if they refuse regional technique or are uncooperative
116
Why is regional anesthesia dependent on surgical procedure?
if operating on different sites of body (Ex. bone grafting from remote site) will require general, may use regional only for analgesia and not anesthesia, may use regional just for post-op pain control
117
What are absolute contraindications for regional anesthesia?
patient refusal
infection at insertion site
coagulopathy (ASRA guidelines)
118
What are relative contraindications for regional anesthesia?
hypovolemia
systemic sepsis
preexisting neurological condition
119
What does regional anesthesia mean?
complete loss of all sensations (autonomic, motor, sensory), surgical anesthesia
120
What does regional analgesia mean?
loss of pain sensation (sensory and autonomic), provides post-operative pain control, but patient will need to go to sleep because not complete anesthesia
121
What are the goals of LA for regional anesthesia?
rapid onset
appropriate duration
lowest toxicity
adequate analgesia/anesthesia
122
What is the primary contributor to success of local anesthetics with regional techniques?
volume of LA
123
If a LA has a faster onset, what does that mean about it's duration?
shorter duration
124
What is the onset of blockade for LA?
autonomic, sensory, motor
125
What does a higher concentration of LA do?
provides better motor block
126
After administering LA, what is the onset of fiber types?
```
B
C and Adelta
A gamma
A beta
A alpha
```
127
What is the recovery of different nerve fiber types?
```
A alpha
A beta
A gamma
C and A delta
B
```
128
What do you need to do to prepare for a peripheral nerve block?
```
resuscitation drugs
narcotics/sedatives
supplemental O2
resuscitation equipment
standards for monitoring
```
129
What does using an immobile needle mean?
attach IV extension tubing to needle instead of directly attaching syringe to needle, allows 2nd person to inject LA while you hold needle
130
What does paresthesia mean with PNB?
occurs with direct contact of needle to nerve, can feel like electric shock or hit funny bone to patient
131
What type of nerve stimulators do you use for PNB?
isolates specific nerve using adjustable, low voltage (
132
Why is the needle insulated?
helps focus current output at tip of needle closest to the nerve, unipolar with insulated shaft and exposed tip
133
If you have a low threshold on your PNS, are you closer or further from the nerve?
close to the nerve, means nerve is accurately localized and can inject less volume
134
About how long does it take for blood levels to peak after injection of LA for PNB?
20 minutes
135
What is the most vascular area of the body to the least vascular area of the body?
tracheal>intercostal>caudal>epidural (lumbar)>brachial plexus>sciatic/femoral>subcutaneous
136
What should you ALWAYS do before each injection for any PNB?
aspirate
137
How much should your incremental doses be for any PNB?
5 mL or less
138
What are 2 major complications of PNB?
intraneural injection
| hematoma
139
What is an intraneural injection?
LA injected directly into the nerve, causes severe pain
140
What is pressure paresthesia with any PNB?
crampy pain from cold LA
141
What is the onset of symptoms for LAST?
1. disorientation
2. metallic taste
3. tingling in the mouth and tongue
4. tinnitus and auditory hallucination
5. muscular spasms
6. seizures
7. coma
8. respiratory arrest
9. cardiac arrest
10. death
142
What is the treatment for LAST?
ABCs!!
Drugs - benzos, thiopental, propofol for seizure control
muscle relaxant to secure airway
CV support
143
What are techniques to avoid LAST?
- patient evaluation (individualize dose, pt allergies)
- premedication (midazolam or CNS depressant)
- preparation (resuscitative drugs)
- equipment (O2 and suction, airway management supplies, IV access)
- prevention (personally check dose, aspirate frequently, monitor CV, vigiliance)
144
What should you document after your PNB?
- nerve block procedure
- approach used
- premedication
- skin preparation
- equipment used (needle and stimulator)
- # of attempts (needle insertions)
- type of response on nerve stimulation
- minimal current (mA)
- local anesthetic (type, concentration, additives, volume)
- abnormal pressure on injection
- signs of block onset
- comments
145
What is the anatomy of the brachial plexus as it leaves the spinal cord? What kinds of anatomy does it form?
```
Roots
Trunks
Division
Cords
Branches/nerves
(Robert Taylor drinks cold beer)
```
146
Where do the roots for the brachial plexus come off the spinal cord?
C5, 6, 7, 8, and T1
147
What are the trunks that form the spinal cord?
superior, middle, inferior
148
What are the cords in the brachial plexus nerve?
lateral, posterior, and medial
149
What two muscles does the brachial plexus go inbetween as it comes out of the neck?
anterior scalene and middle scalene muscles
150
What nerve crosses over anterior scalene muscle that is commonly anesthetized with the brachial plexus?
phrenic nerve which supplies the diaphragm
151
What nerve exits high from the brachial plexus?
musculocutaneous nerve
152
What muscle does the musculocutaneous nerve exit high and go to?
coracobrachialis muscle
153
What nerve exits the brachial plexus high and has to anesthetized separately if a tourniquet is going to be used?
medial brachial cutaneous nerve
154
What are the 3 approaches to a brachial plexus block?
interscalene
supraclavicular
axillary
155
What 2 nerves supply the ring finger?
median nerve and ulnar nerve
156
What is the most common approach to the brachial plexus?
axillary
157
What surgeries would indicate an axillary brachial plexus block?
surgery below the elbow and hand, limited use for surgery above the elbow
158
What are some advantages of an axillary brachial plexus block?
- provides anesthesia for surgery on forearm and wrist
- fewer complications than the supraclavicular or interscalene approach
- probably safest and most reliable
159
What are some limitations of the axillary brachial plexus block?
- arm must be abducted to perform the block
- not for shoulder and upper arm surgery
- musculocutaneous nerve exits sheath proximally and may require separate block
- intercostobrachial and medial cutaneous nerves must be separately blocked for tourniquet or inner, upper arm
160
What is the technique for doing an axillary brachial plexus block?
palpate axillary artery and straddle it between index and middle finger, local skin infiltration tangential across artery,
161
How deep do you usually have to insert the needle for an axillary brachial plexus block?
1-2 cm
162
Where do you want the mA for a nerve response for an axillary brachial plexus block?
0.2-0.4 mA
163
What is the volume of LA needed for an axillary brachial plexus block?
40 mL
164
How much volume can be given for a supraclavicular block?
20-25 mL
165
When doing an axillary brachial plexus block, what should you do if you have paresthesia in the hand?
inject entire volume of LA, do not inject if painful
166
When doing an axillary brachial plexus block, if you have nerve stimulation at 0.2-0.4 mA what should you do?
inject entire volume of LA
167
What happens if you get arterial blood when doing an axillary brachial plexus block?
inject 2/3 volume behind and 1/3 in front of the artery
168
What happens if you obtain venous blood doing an axillary brachial plexus block?
disregard and continue searching for nerve stimulation
169
How can you assess the success of your brachial plexus block?
Push (R) - radial nerve
Pull (M) - musculocutaneous nerve
Pinch ulnar nerve (pinky finger)
Pinch median nerve (middle finger)
170
What nerve is not consistently blocked with an axillary brachial plexus block?
musculocutaneous nerve because it exits sheath proximally above humeral head, can be "rescued" with injection into the belly of the coricobrachialis muscle
171
What 2 nerves do you need to make sure are anesthetized if you are using a tourniquet in the upper extremity?
intercostobrachial nerve and medial brachial cutaneous nerve
172
How can anesthetize the intercostobrachial nerve and medial brachial cutaneous nerve for a tourniquet?
do simple cutaneous injection in the axilla, make skin wheal of 5-7 mL LA
173
What are the LA commonly used for an axillary brachial plexus block?
1.5% mepivacaine (HCO3 + Epi)
2% lidocaine (HCO3 + epi)
0.5% Ropivacaine
174
What LA will precipitate with HCO3?
bupivacaine
175
What surgeries would you want to use an axillary brachial plexus block?
forearm and hand surgery
176
What is the primary landmark you use for an axillary brachial plexus block?
axillary artery
177
What are the end-points where you know you will have a successful axillary brachial plexus block?
nerve stimulation in hand (0.2-0.4 mA)
paresthesia in hand
arterial blood obtained (trans-arterial)
178
What is the LA volume used for an axillary brachial plexus block?
40 mL
179
What are some advantages of interscalene approach?
Appropriate for shoulder surgery
| Risk of pneumothorax is small
180
What is a disadvantage of an interscalene approach?
ulnar nerve may be spared and not blocked
181
What are some complications of an interscalene approach?
unintentional spinal or epidural
puncture vertebral artery
phrenic nerve block (unilateral)
182
Will you ever do bilateral interscalene blocks?
NO, will completely anesthetize phrenic nerve
183
What is the patient positioning for an interscalene block?
supine with neck turned away from block side
184
What is the technique for doing an interscalene block?
palpate sternocleidomastoid, find cricoid ring (C6) and move laterally until finger falls between anterior and middle scalene muscles
185
What artery do you hit if you go too far for an interscalene block?
subclavian artery
186
What is the direction/angle of the needle for an interscalene block?
not directly perpendicular or else can hit vertebral artery
187
What is the goal nerve stimulation for the brachial plexus?
0.2-0.4 mA
188
Twitches in which muscles indicate success of a brachial plexus block?
```
pectoralis muscle
deltoid muscle
triceps muscle
biceps muscle
any twitch of hand or forearm
```
189
What is the volume of LA used for an interscalene block?
20-40 mL (40 mL gives you more coverage)
190
You should never advance your needle beyond what point to avoid complications during an interscalene block?
2.5, avoids risk of cervical cord injury, pneumothorax, and vascular puncture
191
What syndrome can occur with an interscalene block?
Horner's syndrome, causes hoarse voice, mild ipsilateral ptosis, nasal congestion
192
What complication always occurs with an interscalene block?
phrenic nerve block, should avoid in patients with COPD and bronchial asthma
193
What are the indications for an interscalene block?
shoulder, arm, and elbow surgery
194
What are the landmarks for an interscalene block?
clavicular head of sternocleidomastoid muscle, clavicle, external jugular vein
195
What is the nerve stimulation you should see with an interscalene block?
twitch of pectoralis, deltoid, arm, forearm, or hand muscles at 0.2-0.4 mA
