Regional Quiz #3 Flashcards Preview

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Flashcards in Regional Quiz #3 Deck (65):
0

In response to a Sciatic nerve block, what is the interpretation if you get a local twitch of the gluteus muscle, what is the problem and what action should you take?

Your needle is too shallow, so you are getting direct stimulation of the gluteus muscle and so you should continue advancing the needle.

1

In response to a Sciatic nerve block, what is the interpretation if you make contact with the bone but you do not get a local twitch of the gluteus muscle, what is the problem and what action should you take?

The needle is inserted close to the caudal aspect of the iliac bone or the lateral aspect of the sacrum. The problem is caused by needle insertion to superior or medial. You should redirect needle slightly laterally and more caudally.

2

In response to a Sciatic nerve block, what is the interpretation if you make contact with the bone and you get sciatic twitches? What should be your response if this happens?

Because the needle was inserted too laterally(towards the hip joint), or medially(towards the ischial bone), the needle missed the sciatic plane and has hit either the hip joint(too lateral) or the ischial bone(too medially). You should withdraw the needle and redirect either slightly laterally or medially 5-10 degrees.

3

In response to a Sciatic nerve block, what is the interpretation if you get a local twitch of the hamstring muscle, what is the problem and what action should you take?

There is no problem, you should accept and inject as the hamstring is within the sciatic nerve sheath at this level. What is being elicited by a hamstring twitch is stimulation of the main trunk of the sciatic nerve.

4

In response to a Sciatic nerve block, what is the interpretation if your needle is inserted really deep(10 cm) but you have not elicited any twitches and you have not hit bone? What should you do next?

Due to inferior needle placement, the needle has passed through the sciatic notch. You should withdraw the needle and redirect slightly laterally or cephalic.

5

In response to a Sciatic nerve block, what is the interpretation if you get paraesthesia of the genital organs, what is the problem and what action should you take?

The problem is too inferior or medially needle placement. The needle is stimulating the inferior root of the sacral plexus(pudendal nerve). You should withdraw and redirect slightly more laterally or cephalic.

6

What are the acceptable twitches for a successful sciatic nerve block? At what mA is it acceptable to accept and inject?

hamstring, calf, foot or toes;
ceasing between 0.2 - 0.5 mA

7

What are two local anesthesia agents used for sciatic nerve blocks?

0.5% bupivacaine
0.5% ropivacaine

8

For a Sciatic nerve block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Ropivacaine?

Onset 15-20 minutes
Duration of anesthesia 6-12 hours
Duration of analgesia 6-24 hours

9

For a Sciatic Nerve Block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Bupivacaine?

Onset 15-30 minutes
Duration of anesthesia 8-16 hours
Duration of analgesia 10-48 hours

10

What 7 muscles are affected by the tibial nerve?

-biceps femoris
-semitendinosus
-adductor magnus
-popliteus
-gastrocnemius
-soleus
-flexors of the foot

11

What motions are elicited when the tibial nerve is stimulated?

-knee extension
-plantar flexion
-toe flexion

12

Where are 5 areas where sensations are elicited by the tibial nerve?

-heel
-sole of foot
-hip
-knee
-ankle

13

What 5 muscles are affected by the peroneal nerve?

-biceps femoris
-peroneus longus
-peroneus brevis
-extensors of the foot
-extensors of the toes

14

What motions are elicited when the peroneal nerve is stimulated?

-knee flexion
-foot flexion

15

Where are 4 areas where sensations are elicited by the peroneal nerve?

-anterior leg
-dorsum of the foot
-knee
-ankle

16

Stimulation of the femoral gives you knee _____?

Knee extension

17

Stimulation of the sciatic nerve gives you knee _____?

Knee flexion

18

What segments of the tibial nerve is responsible for muscle motion and sensation?

L4-L5,S1-S3

19

What segments of the peroneal nerve is responsible for muscle motion and sensation?

L4-L5,S1-S2

20

What is the largest peripheral nerve in the body?

The sciatic nerve

21

What nerve roots form the sacral plexus?

Ventral Rami of L4, L5 -S1-S3

22

What is the origination of the tibial nerve?

L4, L5, S1-S3

23

What is the origination of the common peroneal nerve?

L4, L5, S1 and S2

24

Which is most lateral, the common peroneal nerve or the tibial nerve?

The common peroneal nerve

25

Whats the indication for a sciatic nerve block?

Lower limb surgery

26

What are 2 other blocks that the sciatic nerve block is often combined with as a supplement block?

1. Femoral block
2. Psoas compartmental block

27

What are 5 contraindications to a sciatic nerve block?

1. patient refusal
2. local infection at site of injection
3. coagulopathy
4. preexisting central or peripheral nervous system disorders
5. allergic to the local anesthesia

28

How many nerves stem from the sacral plexus?

7 nerves, 6 collateral branches and 1 terminal branch which is the sciatic nerve. The sciatic nerve is the largest peripheral nerve in the body.

29

What type of surgeries is the posterior approach of the sciatic good for?

knee, calf, Achilles tendon, ankle and foot

30

What complimentary blocks used in conjunction with a block of the sciatic nerve can be used to block the entire leg?

Femoral block
Lumbar plexus block

31

After a successful block of the leg, what can be some issues after surgery is over?

There will be an inability to move the affected leg/foot. The patient will also be unable to have knee flexion. They will probably need a knee brace, walking boot and crutches

32

What position should the patient be in for a sciatic nerve block?

lateral decubitus with a slight tilt forward

33

What is the technique for performing a sciatic nerve block?

sterilize area, insert needle perpendicular to the skin, set stimulator to 1.5 mA, first visible twitches will be the gluteal muscles, once twitches of the calf, foot or toes is elicited decrease current

34

What are the 3 major landmarks that needs to be identified for a Sciatic Nerve Block?

1. Greater Trochanter
2. Posterior Superior Iliac Spine
3. Sacral Hiatus

35

In what 2 instances should LA not be injected during a sciatic nerve block?

1. when patient complains of pain
2. when an abnormally high amount of pressure is needed to inject

36

What is a Popliteal nerve block used for?

To block Sciatic nerve, used for excellent anesthesia of the calf, tibia, fibula, ankle and foot

37

What is a Popliteal nerve block usually utilized for?

For anesthesia/analgesia for surgeries involving the foot, ankle and the lower leg

38

How long does a Lateral Popliteal block with 0.5 mg of Bupivacaine last as opposed to an Ankle block with 0.5 mg of Bupivacaine?

Lateral Popliteal block last 18 hours versus an Ankle block lasting about 6.2 hours

39

What are 5 indications for a Popliteal block?

1. corrective foot surgery
2. foot debridement
3. saphenous vein stripping
4. repair of the Achilles tendon
5. foot/toe amputation

40

How does the Popliteal nerve block differ from the Sciatic nerve block?

As opposed to the more distal Sciatic nerve block, the Popliteal fossa nerve block anesthetizes the distal leg to the hamstring muscles, allowing patients to retain knee flexion.

41

What two nerve trunks make up the sciatic nerve bundle?

The tibial(medial) nerve and the common peroneal(lateral) nerve.

42

Of the two nerve branches of the sciatica, which of the nerves is the larger of the two divisions?

the Tibial nerve

43

What are the terminal branches of the common peroneal nerve?

The terminal branches of the Common Peroneal Nerve is the Deep and Superficial Peroneal Nerves.

44

What nerves come from the Tibial nerve?

Medial Plantar Nerve
Lateral Plantar Nerve
Sural Nerve
Posterior Tibia Nerve

45

When the nerves of the Common Peroneal branches are stimulated what responses are elicited?

Dorsiflexion and Eversion

46

When the nerves of the Tibial Nerve Branches are stimulated what response is elicited?

Plantar Flexion and Inversion

47

What is the only sensory nerve below the knee?

Saphenous nerve

48

What part of the leg does a Popliteal Block affect?

It provides anesthesia of the entire distal 2/3 of the lower extremity with the exception of the medial aspect of the leg which is supplied by the Saphenous nerve, a superficial terminal branch of the femoral nerve.

49

What position should the patient be in for the Popliteal Nerve Block?

Prone, with the foot protruding off the bed in order to detect even the slightest movement

50

What are the landmarks for the Popliteal Nerve Block?

Popliteal Fossa Crease
Tendon of biceps femoris(laterally)
Tendons of semitendinosus and semimebranous(medially)

51

How many cm above the crease between the tendons should the needle be inserted when performing a Popliteal nerve block?

7 cm

52

How many mls of LA should be injected with any peripheral nerve block?

30 - 40 mls, just don't go higher than the toxic threshold.

53

What movement is elicited by stimulation of the Common Peroneal Nerve(CDE)?

Common Peroneal Nerve
Dorsiflexion
Eversion

54

What movement will be elicited by stimulation of the Tibial nerve?

Tibial nerve
Plantar flexion
Inversion

55

What length insulated needle is used to perform a Popliteal Nerve block?

50 mm short bevel

56

What size insulated needle is used to perform a Sciatic Nerve block?

100 mm 21G short belved

57

For a Popliteal Nerve Block, what is the onset time of 0.5% bupivacaine? What is the duration of anesthesia and analgesia?

Onset time 15 - 30 minutes
Duration of anesthesia 5 - 15 hours
Duration of analgesia 6 - 30 hours

58

For a Popliteal Nerve Block, what is the onset time of 0.5 % Ropivacaine? What is the duration of anesthesia and analgesia?

Onset 5 - 30 minutes
Duration of anesthesia 4 - 8 hours
Duration of analgesia 5 - 12 hours

59

When doing a Popliteal Nerve block, what is the problem when a local twitch of the biceps muscle is elicited? What is the interpretation and what is the corrective action?

Direct stimulation of the biceps femoris muscle is due to a too lateral placement of the needle. Withdrawal the needle and redirect more slightly medially(5 - 10 degrees).

60

When doing a Popliteal Nerve block, what is the problem when a local twitch of the semitendinosus/membranous muscle is elicited? What is the interpretation and what is the corrective action?

It is a result of a direct stimulation of the semitendinosus/membranous muscles and is a result of too medial placement of the needle. You should withdraw the needle and redirect more slightly laterally(5 - 10 degrees).

61

When doing a Popliteal Nerve block, what is the problem when a local twitch of the calf muscle is noted when neither toe or foot movement is elicited? What is the interpretation and what is the corrective action?

This is a result of stimulation of the muscle branches of the sciatic nerve. The problem is these muscles are often outside the sciatic sheath. One should disregard and continue advancing needle until twitches of the foot and toes is elicited.

62

When doing a Popliteal Nerve block, what is the problem when you puncture the vascular? What is the interpretation and what is the corrective action?

Blood in the syringe indicates puncture of the popliteal vein or artery. The problem is too medial needle placement. The anesthesia provider should withdraw the needle and redirect more laterally.

63

When doing a Popliteal Nerve block, what is the problem when the needle makes contact with bone? What is the interpretation and what is the corrective action?

The problem is too deep needle insertion. Either the nerve was missed or motor response was not appreciated and so the femur was hit by the needle. The needle should be withdrawn slowly and if no twitch is appreciated, the needle should be redirected.

64

What is the most important complication of a Popliteal Nerve Block?

Avoid a combination of epinephrine in LA and application of a tourniquet over the injection site as it can lead to nerve ischemia.