Exam 2

Question 1

Local anesthetics are ______ blockers

Answer 1

Calcium channl

Question 2

How do local anesthetics work?

Answer 2

Prevent depolarization, blocks conduction of nerve impulses to inhibit pain

Question 3

What nerve fibers are affected by local anesthesia, and what effect does that have?

Answer 3

A-delta & C fibers first > Provides analgesia

A-beta & A-alpha second > paralysis

Question 4

Order of sensation disappearance with local anesthesia

Answer 4

Pain > Cold > Warmth > Touch > Joint pain > deep pressure > motor blockade (paralysis)

Question 5

What are the 3 basic units of local anesthetics?

Answer 5

1. Aromatic group (benzene ring) > Lipophilic
2. Intermediate chain - Ester-linked or Amide-linked
3. Tertiary Amine (amino tail) > Hydrophillic

Question 6

How does lipid solubility affect local anesthetic efficacy?

Answer 6

1. Higher solubility = Higher potency

2. Smaller lipophilic modules = faster onset of action

Question 7

Ester-linked local aesthetics

Answer 7

Procaine, tetracaine, proparacane

Question 8

Amine-linked local anesthetics

Answer 8

Lidocaine, bupivacaine, ropivacaine, mepivacaine

Question 9

How does pKa influence local anesthetics?

Answer 9

More basic&raquo_space; More rapid onset, greater potency

Question 10

How does addition of vasoconstrictors (epinephrine, etc.) influence local anesthetics?

Answer 10

1. Delays absorption & onset
2. Prolongs duration
3. May increase intensity of blockade

Question 11

How does addition of bicarbonate influence local anesthetics?

Answer 11

Increases pKa (more basic)&raquo_space; more rapid onset

Question 12

List common adjuvants to local anesthesia

Answer 12

Opioids
Vasoconstrictors
Alpha-2 Agonists

Question 13

How are opioids commonly used with local anesthetics?

Answer 13

1. Enhance epidural anesthesia
2. Improve analgesia without affecting motor blockade
3. With lidocaine +/- ketamine for CRIs

Question 14

How do alpha-2 agonists affect local anesthetics?

Answer 14

1. Enhance epidural analgesia
2. Enhance peripheral nerve blocks
3. Increase duration

Question 15

How does bupivacaine compare to lidocaine?

Answer 15

1. Slower onset
2. Longer duration
3. May be more cardiotoxic

Question 16

Tuohy needle

Answer 16

Curved, blunt tip needle used for epidurals.
Less likely to penetrate perineurium
Better tactile sensation

Question 17

Spinal needle

Answer 17

Very sharp with short stylet. Used for spinal injections & CSF colection

Question 18

Insulated nerve block needle

Answer 18

1. Used with peripheral nerve stimulator
2. Directs current to tip
3. Helps identify target nerves before injection

Question 19

How is ultrasound used for regional anesthesia?

Answer 19

1. Used alone or with peripheral nerve stimulator

2. Allows for visualization of nerve for more precise placement

Question 20

Peripheral Nerve Stimulator

Answer 20

1. Used with nerve block needles
2. As needle approaches target, less current is needed to stimulate response
3. When response is elicit at 0.2 - 0.6 mA, okay to inject

Question 21

When is the best time to use an incision block?

Answer 21

Pre-op; but sometimesat closure

Question 22

Mepivacaine & Ropivacaine for IA block

Answer 22

Less chondrotoxic

Question 23

What opioid can be used for IA block?

Answer 23

Preservative-free morphine; preservatives may play a role in chondrotoxicity

Question 24

Why should steroids be used with caution for IA injection?

Answer 24

Can be chondrotoxic depending on dose & duration

Question 25

What are the 2 types of testicular blocks?

Answer 25

1. Direct injection | 2. Spermatic cord

Question 26

What local anesthetics are used for testicular or line blocks?

Answer 26

Lidocaine or bupivacaine

Question 27

How will eye react if retrobulbar block is successful?

Answer 27

1. Pupil dilated | 2. Central eye position

Question 28

What area is blocked by brachial plexus block?

Answer 28

Distal humerus to digits.

Question 29

Can blind approach be used for brachial plexus block?

Answer 29

Not recommended. Use nerve stimulator and/or ultrasound.

Question 30

Rostral maxillary (infraorbital) block

Answer 30

1. Needle inserted into infraorbital foramen | 2. Blocks from 3rd premolar rostrally to midline (soft tissue, teeth, bone, upper lip, lateral nasal mucosa)

Question 31

Caudal maxillary block

Answer 31

1. Insert needle perpendicularly behind 2nd maxillary molar | 2. blocks caudal maxilla (hard& soft palate, teeth & bone) rostrally to midline.

Question 32

Rostral mandibular (middle mental) block

Answer 32

1. Insert needle into middle mental foramen | 2. Blocks rostral soft tissue but not teeth

Question 33

Caudal mandibular (inferior alveolar) block

Answer 33

1. Needle inserted medial to mandibular notch in line with lateral canthus 2. Blocks ipsilateral mandible to midline