lower extremity nerve blocks

Question 1

regional anesthesia CA

Answer 1

patient refusal
inability of pt to cooperate
coagulopathy
preexisting neuro deficits (document baseline)
skin infection
sepsis

Question 2

peripheral nerve block risks

Answer 2

LA toxicity
allergic response PAVA
permanent or transient nerve damage
pt uncomfortable positioning during durg (turniket)
incomplete blocks

Question 3

esters

Answer 3

“one eyed”
chloroprocaine

metabolixed by plasma cholinesterase’s, greater potential for producing allergic reactions

Question 4

amides

Answer 4

two eyed
lidocaine
bupivocaine
metabolized by hepatic processes

Question 5

rate of absorption dependent on site

Answer 5

intercostals
caudal
epidural
brachial plexus
sciatic
lumbar plexus
femoral

Question 6

local toxicity s/sx

Answer 6

tongue numbness
lightheadedness
dizzy 
tinnitus
disorientation
visual dist
seizures
CNS depression
resp dep/arrest
cv instability

(wont see neuro change when under general anesthesia, order - cns, reap, cv)

Question 7

sciatic nerve block

Answer 7

ventral branches lumbosacral plexus L4-S3
combine w popliteal, achilles tendon

greater trochaner to posterior superior iliac spine, greater trochanger to sacral hiatus, 5 cm

dorsiflexion or eversion of foot indicates common peroneal branch (more lateral)
plantar flexion of foot and toes indicates tibial branch (more medial)

vol 20-30ml

Question 8

femoral nerve block

Answer 8

both sensory and motor

anesthesia to anterior portion thigh, knee, small part of medial foot,
results in inability to abduct leg or extend lower leg

find fem pulse, lateral
22G 50mm needle perpendicular to skin advanced cephalad at 45 degree angle
25-35 ml vol

Question 9

popliteal nerve block

Answer 9

foot and ankle surgery
popliteal fossa crease, biceps femoris tendon, semitendinosus and semimembranousis muscles
nerve stim foot twitch or toes
30 ml
7cm above pop crease, insert at midpoint or a bit lateral

Question 10

ankle block “fan”

Answer 10

22G, 38mm B bevel
5-7ml/nerve (5)
dont use epi on end organs

1) posterior tibial (start w bc biggest) - medial maleolus, post to tib artery, hit bone
2) deep peroneal - insert needle lateral to hallucis long tendon at level of ankle, contact bone, withdraw 2-3mm

3) saphenous - just above medial malleolus
4) superficial peroneal - lateral malleolus
5) sural - behind lateral malleolus