Lecture 16 10/31/24

Question 1

What are the goals of preemptive locoregional nerve blockade?

Answer 1

-block afferent sensory information
-prevent noxious stimulus from reaching CNS
-reduce need for systemic drugs
-reduce adverse drug effects
-promote pain-free and comfortable recovery

Question 2

Which drugs are used for nerve blocks?

Answer 2

-opioids
-alpha2 adrenoceptor agonists

Question 3

How can nerves be located for nerve blocks?

Answer 3

-blind injection
-nerve locator
-peripheral nerve stimulators
-ultrasound-guided blocks

Question 4

What are the benefits to using a nerve locator?

Answer 4

-closer to the nerve
-more effective
-apply as little drug as possible

Question 5

What are the characteristics of an electrical nerve stimulator?

Answer 5

-allows localization of the nerve
-uses variable current in the stimulating device

Question 6

Which nerve blocks are done in the head area?

Answer 6

-ophthalmic n.
-auriculotemporal n.
-maxillary n.
-mandibular n.
-mental n.
-infraorbital n.

Question 7

What are the branches of the trigeminal nerve?

Answer 7

-ophthalmic n.
-maxillary n.
-mandibular n.

Question 8

What are the characteristics of the maxillary nerve block?

Answer 8

-middle branch of trigeminal n.
-blocks sensory innervation to entire upper dental arcade, soft palate, hard palate, and muzzle

Question 9

How is the maxillary nerve blocked through the oral cavity?

Answer 9

-needle is introduced into the mucosa
-caudal to last molar
-injection at junction of hard and soft palate

Question 10

How is the maxillary nerve blocked through the zygomatic arch?

Answer 10

at corner of the zygomatic arch and the caudal border of the maxilla

Question 11

Which other approach can be used to block the maxillary nerve?

Answer 11

infraorbital canal

Question 12

What are the characteristics of the infraorbital nerve block?

Answer 12

-branch of maxillary nerve
-blocks sensory innervation to rostral part of maxilla
-blocks anterior upper teeth, nose, and upper lip

Question 13

What are the characteristics of the mandibular nerve block?

Answer 13

-blocks entire lower dental arcade, tongue, and lower lip
-blocks nerve as it enters mandibular foramen
-on medial surface of mandible
-foramen is palpated from inside mouth
-intraoral or extraoral approach

Question 14

What are the characteristics of the mental nerve block?

Answer 14

-rostral continuation of mandibular nerve
-mental foramen located caudal and ventral to lower canine tooth
-blocks sensory innervation to rostral portion of mandible
-desensitizes lower incisors, canine teeth, and lower lip

Question 15

How is the mental nerve block performed?

Answer 15

-mandibular labial frenulum is retracted ventrally
-needle is inserted into the rostral aspect

Question 16

What are the characteristics of the brachial plexus?

Answer 16

-originates from C5, C6, C7, C8, and T1 (sometimes T2) spinal nerves
-gives rise to radial, ulnar, median, and musculocutaneous nerves

Question 17

What are the techniques for an axillary brachial plexus block?

Answer 17

-RUMM block/at level of the arm
-digit nerve blocks over the digits
-regional intravenous block/lower extremities

Question 18

What are the indications for axillary brachial plexus blocks?

Answer 18

elbow and distal procedures

Question 19

What are the landmarks for an axillary brachial plexus block?

Answer 19

-medial to the shoulder
-direct needle toward the first rib

Question 20

What are the indications for epidural anesthesia?

Answer 20

-cesarean section
-pelvic or hind limb surgery
-abdominal exploratory
-perineal or peri-anal procedures

Question 21

What is the epidural space?

Answer 21

space between the vertebral column and the dura mater

Question 22

What are the steps to finding the L-S junction?

Answer 22

-pull legs forward in ventral or lateral recumbency
-palpate iliac crests with first and third finger of non-dominant hand
-palpate L7 spinous process with pointer finger
-insert needle 45-60 deg. to the horizontal plane

Question 23

Which layers must the needle pass through to reach the epidural space?

Answer 23

-skin
-SQ and interspinous ligament
-interarcuate ligament (pops)

Question 24

What is the most common epidural medication combination?

Answer 24

bupivacaine and morphine

Question 25

What are the characteristics of epidural morphine?

Answer 25

-full opioid agonist
-hydrophilic/poor lipid solubility; less systemic uptake
-onset around 60 minutes
-duration of 16-24 hours
-no motor blockade

Question 26

What are the adverse effects of epidural anesthesia?

Answer 26

-hypotension
-urinary retention
-motor blockade in both pelvic limbs
-cranial migration
-cardiovascular and resp. depression
-pruritus
-abnormal hair regrowth

Question 27

Which nerve blocks are used for the hind limbs?

Answer 27

-femoral: L4-L6
-sciatic: L6-S3

Question 28

How is the sciatic nerve block approached?

Answer 28

between ischiatic tuberosity and greater trochanter

Question 29

What is the use of the femoral nerve block?

Answer 29

block craniomedial innervation of the thigh