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Pharm Final review > Principles Final - upper blocks > Flashcards

Principles Final - upper blocks Flashcards

1
Q

What is the purpose of regional anesthesia?

A

Provides site-specific, long-lasting, and effective anesthesia and analgesia

Suitable for many surgical procedures

Improves analgesia

Can have a major impact on patient satisfaction
Optimal pain relief

Less side effects (i.e., PONV)

Early mobilization

Lower costs

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2
Q

What does regional anesthesia reduce?

A

Morbidity
Mortality
Need for reoperation

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3
Q

Is the success and safety of regional anesthesia highly dependent on the accurate delivery of the correct dose of local anesthetic?

A

YES

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4
Q

What are some risks of regional anesthesia?

A

Systemic toxicity
Infection
Bleeding
Permanent nerve injury

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5
Q

What are some risks of regional anesthesia?

A

Systemic toxicity
Infection
Bleeding
Permanent nerve injury

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6
Q

Where does the pre-block stage usually occur?

A

Blocks can be performed in the OR , but preferable to administer block in a separate room or area due to “soak time”

Time it takes local anesthetics to cross the cell membrane, block action potentials, and produce either analgesia or surgical anesthesia

All supplies should be assembled and readily available prior to beginning the block

Oxygen, monitoring equipment, emergency airway equipment, resuscitative equipment

Emergency medications
Epinephrine, Atropine, Phenylephrine, Propofol, Succinylcholine, Midazolam, Intralipid

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7
Q

Do you monitor the patient at all times while doing regional anesthesia?

A

YES

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8
Q

What are some tips about the premedication and sedation stage?

A

Titrated to effect for individual patient and block performed

Patient should be conscious enough to report nerve contact

Common to use a combination of several of the following drugs:
Midazolam
Fentanyl
Alfentanil
Ketamine
Propofol

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9
Q

What are the two common techniques for the block performance stage?

A

Nerve Stimulation

Ultrasound Imaging

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10
Q

Basics of Technique and Equipment of Nerve Stimulation (NS) Technique

A

Low-current electrical impulse is applied to a peripheral nerve

Produces stimulation of motor fibers, indicating proximity to the nerve

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11
Q

What are the limitations of the nerve stimulation technique?

A

Inconsistent results

Variations in electrical properties of different nerve stimulators

Other variables that effect the ability to stimulate nerves:

Conducting area of the electrode (stimulating needle vs. stimulating catheter tip)

Electrical impedance of the tissues

Electrode-to-nerve distance

Current flow

Pulse duration

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12
Q

Practical guidelines for nerve stimulation

A

NS should be set to deliver a current of 1 to 2 mA

Once the needle is inserted into the skin, the assistant should maintain constant aspiration of the syringe plunger observing for blood return in the needle tubing

The needle is in the proximity of the nerve when a motor response is seen between 0.3 to 0.5 mA

***Placing the needle where a motor response only requires 0.1 to 0.2 mA increases the risk of intraneural injection and should be avoided

Once the nerve is located, inject 2-3 cc of local anesthetic (LA) and observe for loss of motor twitch

Inject remaining medication in 5cc increments, aspirating the plunger q 5cc

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13
Q

What should nerve stimulation be set to?

A

1 to 2 mA

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14
Q

What increases the risk of intraneural injection?

A

Placing the needle where a motor response only requires 0.1 to 0.2 mA (The needle is in the proximity of the nerve when a motor response is seen between 0.3 to 0.5 mA)

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15
Q

What are the benefits of ultrasound technique vs. nerve stimulation?

A

Anesthetist can adjust needle and catheter placement under direct visualization

Fewer needle attempts

Increased block success

Improved sensory and motor blocks

Reduced onset times

Prolonged block duration

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16
Q

Practical guidelines for ultrasound technique

A

Sterile preparation of the skin and US probe

Use adequate US gel to improve structure visualization

Best to identify reliable anatomic landmarks (bone or vessel) with a known relation to the target nerve
“Trace” or follow the nerve to the optimal block location

In-plane approach to needle insertion allows for better visualization

When close to the nerve a 1-2mL test dose of D5W can be injected to visualize the spread

D5W will appear as a hypoechoic expansion and illuminate the surrounding area, improving visibility of the nerves and block needle

Steep learning curve with US technique

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17
Q

When do you use a test dose of 1-2 cc’s of D5W?

A

For ultrasound technique. When close to the nerve a 1-2mL test dose of D5W can be injected to visualize the spread

D5W will appear as a hypoechoic expansion and illuminate the surrounding area, improving visibility of the nerves and block needle

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18
Q

The in-plane technique

A

The needle is aligned in the plane of thin ultrasound beam allowing the visualization of the entire shaft and the tip. (YOU SEE THE WHOLE NEEDLE)

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19
Q

Out of plane technique

A

the ultrasound beam transects the needle, and the needle tip or the shaft is observed as a bright spot in the image. (YOU JUST SEE A BRIGHT SPOT)

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20
Q

Anatomic landmark for interscalene block

A

subclavian artery and scalene muscles

21
Q

Anatomic landmark for supraclavicular block

A

subclavian artery

22
Q

infraclavicular

A

subclavian/axillary artery and vein

23
Q

Axillary

A

axillary artery

24
Q

Needles Single-shot nerve block

A

22- to 24-gauge insulated needles with short bevels

25
Q

Needles for Continuous nerve block

A

18- to 20-gauge needles when using a catheter-through-needle technique

26
Q

Catheters

A

Catheter is similar to an epidural catheter

18-gauge insulated Tuohy needle with NS capability used for insertion

27
Q

Discharge criteria after a block

A

Stable vital signs in the PACU

Pain well-controlled upon discharge

Advise patient of risks associated with an anesthetized limb

Potential for pressure neuropathies

Risk of burns when cooking

28
Q

What is an absolute contraindication for any block?

A

PATIENT REFUSAL

Absolute contraindications include patient’s refusal, local infection, active bleeding in an anticoagulated patient, and proven allergy to local anesthetic.

Other contraindications:
Local infection
Systemic anticoagulation

Schizophrenic patients should receive PNB accompanied by general anesthesia

Existing neurologic deficits (*potential contraindication)
Clear and thorough documentation of current neurologic deficits prior to block performance

29
Q

Is local anesthetic concentration dependent?

A

Yes

30
Q

How does nerve damage occur with blocks?

A

May result from intraneural injection

31
Q

What are the types of upper extremity blocks?

A

Brachial Plexus Blocks:
Interscalene
Supraclavicular
Infraclavicular
Axillary

Radial Nerve Blocks

Ulnar Nerve Block

Median Nerve Block

32
Q

Where does the brachial plexus arise from?

A

The anterior primary rami of C5-C8 and T1 spinal nerves.

Plexus consists of 5 roots, 3 trunks, 6 divisions (2 per trunk),
3 cords, and 5 major terminal nerves

33
Q

Axillary nerve

A

Originates C5-C6
Posterior cords

34
Q

Radial nerve

A

C5-C8 and T1 roots
Upper and middle trunks
Posterior divisions
Posterior cords

35
Q

Median nerve

A

C5-C8, T1
All trunks
Lateral and medial cords

36
Q

Musculocutaneous nerve

A

C5-C7 roots
Upper and middle trunks
Anterior divisions
Lateral cord

37
Q

Ulnar nerve

A

C7-C8, T1
Lower trunk
Anterior division
Medial cord

38
Q

What is the indication for axillary block?

A

Surgery distal to the elbow

39
Q

What are the contraindications to axillary block/

A

Local infection
Neuropathy
Bleeding risk

40
Q

Indication for interscalene block?

A

Indicated for surgical procedures involving the shoulder and the upper arm

Roots C5-C7 are most densely blocked with this approach
The ulnar nerve originating from C8-T1 may be spared
*NOT appropriate for surgery at or distal to the elbow

41
Q

Contraindications to interscalene block

A

Local infection
Severe coagulopathy
Local anesthetic allergy
Patient refusal

42
Q

Indication for Supraclavicular Block

A

Dense anesthesia of the brachial plexus for surgical procedures at or distal to the elbow

43
Q

Issues with supraclavicular block

A

Historically, the block fell out of favor due to the high incidence of complications that occurred with paresthesia and nerve stimulator techniques. Ultrasound guidance has improved its safety and increased its current use.

44
Q

Indication for intraclavicular block

A

Brachial plexus block at level of cords

For surgical procedures at or distal to the elbow
The intercostobrachial nerve is spared (T2 dermatome)

45
Q

Most common sites for terminal nerve blocks

A

elbow and the wrist are the most common sites

46
Q

Intravenous Regional Anesthesia (Bier Block)

A

Indications:
Surgical procedures of short duration (45-60 minutes)
Trigger finger release
Carpal tunnel release

47
Q

More on bier block (IV regional)

A

Technique:
IV Catheter is inserted on the dorsum of the surgical hand
A double pneumatic tourniquet is placed on the arm
The extremity is elevated and exsanguinated by tightly wrapping an Esmarch elastic bandage from distal to proximal direction
The distal tourniquet is inflated, then the proximal tourniquet is inflated.
Esmarch bandage removed, and 50 mL 0.5% preservative free lidocaine is injected over 2-3 minutes through the IV catheter which is subsequently removed
Anesthesia is usually established after 5-10 minutes
Tourniquet pain usually develops in 20-30 minutes at which time the distal tourniquet can be deflated
Once the distal tourniquet is re-inflated, the proximal tourniquet can be deflated to allow for drift of the LA under the tourniquet thereby reducing tourniquet pain
The tourniquet must remain inflated for at least 20 minutes to prevent LA toxicity
Slow “cycling” tourniquet deflation can reduce the risk of LA toxicity
Ask the patient if they are experiencing a metallic taste in their mouth or ringing in their ears. If they are, keep O2 and monitors on the patient and continue to monitor until it subsides.

48
Q

Which block is NOT appropriate for surgery at or distal to the elbow?

A

interscalene block

49
Q

Which block fell out of favor due to paresthesias but has been utilized more since ultrasound?

A

supraclavicular

Pharm Final review (24 decks)

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