Regional anesthetic techniques

Question 1

Features of amino amide structure & examples:

Answer 1

hepatic metabolism (slower), but toxic accumulation is more likely

ex. lidocaine, bupivacaine, mepivacaine

Question 2

MOA local anesthetics?

Answer 2

block sodium channel

Question 3

Local anesthetics are considered weak bases? T/F

Answer 3

True, ( becomes ionized in acidic pH causing ion trapping)

- reason should not inject lidocaine into infected tissues which are considered acidic/ so LA does not work

Question 4

Which local anesthetic has a short onset & short duration?

Answer 4

Lidocaine: fast onset & 1-2 hr duration–> max dose: 5 mg/kg

Question 5

What fiber types are more susceptible to local anesthetic?

Answer 5

smaller nerve & myelinated fibers

Question 6

Local anesthetic toxicity is associated with…

Answer 6

high dose, IV injection & reduced biotransformation/ elimination (liver or renal)

Question 7

What CNS signs are associated with local anesthetic toxicity?

Answer 7

depression of cortical inhibitory pathways, impaired vision, seizures, CNS depression/coma

Question 8

What CV signs are associated with local anesthetic toxicity?

Answer 8

bradycardia, changes to ECG, VPC, reduced myocardial contractility & cardiac arrest

Question 9

Topical anesthesia- block indications

Answer 9

superficial mucosal tissue

Question 10

Topical anesthesia- what nerves are blocked?

Answer 10

free nerve endings & nociceptors

Question 11

Local infiltration- block indications

Answer 11

skin & underlying tissue

Question 12

Local infiltration- nerves blocked

Answer 12

free nerve ending, nociceptors & terminal nerve branches (does not target specific nerve)

Question 13

What do intraneural injections produce?

Answer 13

Nerve damage

Question 14

Infraorbital nerve block contraindication

Answer 14

risk of ocular puncture in cats & brachycephalic animals!

Question 15

Maxillary nerve block:

Answer 15

o Nerves blocked: maxillary
o Use: dental; unilateral mandible
o Area desensitization: maxilla (+teeth), paranasal sinus & sinus cavity

Question 16

Inferior alveolar (mandibular) nerve block:

Answer 16

o Nerves blocked: mandibular nerve (branch of trigeminal)
o Use: dental; mandibular teeth extraction
o Area desensitization: mandible, mandibular teeth & ipsilateral lower lip

Question 17

Inferior alveolar (mandibular) block adverse effect?

Answer 17

desensitize lingual nerve leading to self mutilation of the tongue during recovery

Question 18

Why would you select lumbar paravetebral block over inverted L technique?

Answer 18

no LA at margins of surgical site & provides better analgesia than an inverted l technique

Question 19

What nerves are being blocked with the lumbar paravertebral block?

Answer 19

T13-L1 &L2

Question 20

Where is the epidural space?

Answer 20

located between interarcutae ligament & duramater

Question 21

What epidural space is commonly used in SA?

Answer 21

o Lumbo-sacral space is used in small animal (less risk of piercing spinal cord- since it ends at L6-L7)

Question 22

What epidural space is commonly used in LA?

Answer 22

o Sacro-coccygeal space because spinal cord ends at S1

Question 23

Landmark for epidural injection- SA?

Answer 23

o Iliac crest, medial sacral crest & spinous process L7

Question 24

Why is it important to know whether you are epidural or spinal injection?

Answer 24

They need different volumes of LA; which spinal injection requires much lower dose than epidural space!

Question 25

How do you know if you are in the epidural space?

Answer 25

Hanging drop technique OR loss of resistance to injection

Question 26

Why should you use small volumes in the sacro-coccygeal epidural in horses?

Answer 26

Typically use a small amount in horses, because large volumes can lead to pelvic limb paralysis