Peripheral Nerve Blocks Flashcards

1
Q

What is a potential complication of a brachial plexus PNB in relation to breathing?

A

Phrenic nerve blockade which would paralyze the diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are risks/contraindications for PNB?

A

Patient cooperation/participation.
Bleeding disorders and/or pharmacologic anticoagulation.
Sites of infection.
Existing nerve injury (law suit).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What three things need to be considered when choosing a specific LA?

A
  1. Desired onset.
  2. Desired duration.
  3. Desired sensory/motor block.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which LA typically does not have a good motor block?

A

Bupivacaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the maximum dose of lidocaine?

A

4 to 7mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the maximum dose of bupivacaine?

A

2.5 to 3mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the maximum dose of ropivacaine?

A

2.5 to 3mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the duration of action for lidocaine PNB?

A

Maybe up to 6 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the duration of action for bupivacaine or ropivacaine PNB?

A

12-18 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many mg/ml if drug is 3%?

0.3%

A

30mg/ml

3mg/ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many mcg/ml if drug is 1:50,000?

1:10,000?

A

20mcg/ml

100mcg/ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why might epinephrine not be used with bupivacaine or ropivacaine PNB?

A

The block my out last the duration of the epinephrine so it may not be useful.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe a situation where field block technique is used:

A

Commonly used in dental procedures and “fan” technique by surgeon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which nerves does field block technique target?

A

Terminal cutaneous nerves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe paresthesia technique:

A

Use known anatomic relationships and surface landmarks to guide needle. When needle makes direct contact with a sensory nerve, the patient can feel it/movement occurs. Older technique not used much anymore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

With nerve stimulation technique, at what mA would it be considered close enough to inject?

A

0.4-0.5 mA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What mA indicates intraneural needle placement?

A

0.2 mA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How much LA is injected with nerve stimulation approach?

A

30-40ml with gentle aspiration and divided doses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What MHz are used by ultrasound technique?

A

1 to 20 MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T/F: Hard structures will show up white on ultrasound? Empty/fluid filled?

A

True:
Hard=white
Empty/fluid filled=dark

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is echogenicity?

A

The degree of efficiency with which sound passes through a substance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T/F: Hyperechoic is a structure or substance through which sound easiliy passes. Appears dark or black on the ultrasound screen?

A

False:

Hypoechoic=dark/black=sound easily passes through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is anechoic?

A

No reflection via sound waves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Ultrasound creates a two-dimensional or three-dimensional grayscale image?

A

Two-dimensional

25
Q

Which probe (linear or curvilinear) uses high frequency and offers less tissue penetration?

A

Linear

26
Q

Which type of probe is typically used for superficial nerves?

A

Linear

27
Q

Nerves are best imaged in short-axis or long-axis mode?

A

short-axis.

28
Q

Which needle insertion technique does the needle follow the longitudinal (long axis) plane? Transverse (short-axis plane)?

A

In-plane needle alignment=long axis, longitudinal.

Out-of-plane alignment=transverse, short-axis

29
Q

With which needle technique will you be able to see the whole needle?

A

Long-axis/longitudinal.

30
Q

What are the 8 advantages of continuous PNB over single injection nerve block?

A
  1. Reduction in resting and dynamic pain.
  2. Reduction in supplemental analgesia requirement.
  3. Reduction in opioid related side effects.
  4. Reduction in sleep disturbance.
  5. Improved patient satisfaction.
  6. Improved patient ambulation.
  7. Accelerated resumption of passive joint range-of-motion.
  8. Reduced time to discharge.
31
Q

What are the 6 complications of continuous PNB?

A
  1. Systemic LA toxicity.
  2. Cather retention.
  3. Nerve injury.
  4. Infection.
  5. Retroperitoneal hematoma.
  6. Increased risk of falling.
32
Q

How is the brachial plexus broken down?

A

5 Roots>3 Trunks> 6 Divisions> 3 Cords> 5 Branches

33
Q

Which brachial plexus block is indicated for shoulder surgery?

A

Interscalene block

34
Q

What nerve roots are most densely blocked using the interscalene approach?

A

C5-C7

35
Q

For complete surgical anesthesia of the shoulder, what must also be done in conjunction with an interscalene block?

A

C3-C4 cutaneous branches may need to be blocked via superficial cervical plexus block or local infiltration.

36
Q

What are contraindications for interscalene block?

A
  1. Local infection.
  2. Severe coagulopathy.
  3. LA allergy.
  4. Patient refusal.
37
Q

What other nerve will be blocked if interscalene block is properly performed?

A

Ipsilateral phrenic nerve

38
Q

What are some other considerations with interscalene block?

A
  1. Horner’s syndrome=stroke like symptoms
  2. Recurrent laryngeal nerve =induces hoarsness
  3. Vertebral artery injection
  4. Accidental spinal or epidural injection.
  5. Pneumothorax.
39
Q

What would inadvertent vertebral artery injection cause?

A

Immediate seizure activity.

40
Q

What are the three components to Horner’s Syndome?

A
  1. Ptosis=droopy eye
  2. Myosis=pupil constricts.
  3. Anhydrosis=no sweat/no tears/reddened
41
Q

What ganglia near an interscalene block innervates the face?

A

Superior cervical ganglia

42
Q

Which two muscles is the interscalene block placed directly in between?

A

In between middle and anterior scalene muscles.

43
Q

Which brachial plexus block is associated with the highest incidence of pneumothorax?

A

Supraclavicular block

44
Q

What is surgical procedures is a supraclavicular block used for?

A

Usually anything distal to the elbow, not ideal for shoulder.

45
Q

Why is the supraclavicular block not ideal for shoulder surgery?

A

It does not reliably anesthetize the axillary and suprascapular nerves

46
Q

On ultrasound, what will we look for when doing a supraclavicular block?

A

Stop-light like nerves in a row of three. Between the trunks and divisions.

47
Q

T/F: Ultrasound will show a stop-light like picture when doing a supraclavicular block that shows the nerves as hyperechoic?

A

True

48
Q

What are complications of supraclavicular block?

A
  1. Ipsilateral phrenic nerve palsy (50%).
  2. Horner’s Syndrome.
  3. RLN palsy.
  4. Pneumothorax*.
  5. Subclavian artery puncture.
49
Q

Which brachial plexus block is of highest risk for bleeding?

A

Infraclavicular block: You can not place direct pressure at puncture site.

50
Q

T/F: Infraclavicular block is blocked at the level of the trunks

A

False; level of the cords.

51
Q

What surgical procedures is the infraclavicular block appropriate for?

A

Procedures at or distal to the elbow.

52
Q

Which nerve is spared with infraclavicular blocks?

A

Intercostobrachial nerve is spared (T2 Dermatome).

53
Q

What part of the brachial plexus is targeted for an axillary block?

A

The terminal branches ulnar, radial, and median

54
Q

Where is the needle placed for an axillary block?

A

Just posterior and lateral to the pectoral muscle

55
Q

Which two branches are not involved in axillary block?

A

Musculocutaneous and axillary nerves

56
Q

What are the favored sites for injection for blocking individual terminal nerves?

A

elbow and wrist.

57
Q

What block is typically done for carpal tunnel release?

A

Bier Block

58
Q

What is the time frame for duration of a Bier block?

A

45-60 mins

59
Q

How long must the cuff pressure be maintained after LA injected for Bier block?

A

15-20mins