Flashcards in Local Anesthetic Agents 3 Deck (57)
What are 5 examples of blocks that can be used for local anesthesia of the flank?
- Inverted L block
- Incisional block
- Proximal paravertebral block
- Distal paravertebral block
The objective of a proximal paravertebral block is to block which 3 nerves?
T13, L1, L2
Where is the site of needle insertion for a proximal vertebral block?
5 cm from midline and transversely in line between 2 dorsal spinous processes
What gauge and length needle is used for a proximal paravertebral block?
- 16 or 18 g
- 12-15 cm
To block the ventral branch in a proximal paravertebral block, how much local anesthetic is given?
To block the dorsal branch?
- 15 mL below intertransverse ligament
- 5 mL above ligament & leveled with dorsal surface of transverse processes
What are 4 advantages of a proximal block of infiltrative analgesia?
- Wide & uniform area of analgesia & muscle relaxation
- Incision site not disrupted
- Infiltrative block may take 45 min to desensitize area
- Faster technique
What are 4 disadvantages of a proximal block of infiltrative analgesia?
- Technically difficult (obese cattle)
- Scoliosis dye to back muscle paralysis (makes closure more difficult)
- Vital structures (aorta & vena cava)
- Loss of motor control in pelvic limb (caudal migration)
How do you find the site to give the first injection in a distal paravertebral block?
- Find last rib then vertebrae just behind it.
Which 3 nerves are done in a distal paravertebral block?
Which nerve is purposefully skipped?
- L1, L2, L4
How much local anesthetic is given in a distal paravertebral block?
How is it given?
- 10-20 mls 2% lidocaine then withdraw needle short distance dorsal & caudal to transverse process & inject additional 5 ml
- injected in a fan-shaped infiltration ventral to each process.
What are 4 advantages of a distal paravertebral block?
- Lack of scoliosis
- Lack of risk of penetrating major blood vessels
- Minimal weakness in pelvic limb
- Minimal ataxia
What are 2 disadvantages of a distal paravertebral block?
- Larger doses of anesthetic
- Variations in efficiency (nerves may follow variable anatomic pathways)
What are 4 examples of equine cranial blocks?
Infraorbital nerve blocks provide anesthesia where?
What are 2 examples of indications for this?
- Anesthesia of upper lip & nose
- Suturing of nasal laceration, placement of nose ring in cattle
Where does an infraorbital nerve block desensitize?
Entire anterior half of face from foramen rostrally.
How can you find the location to give an infraorbital nerve block in a horse?
Feel for the bony lip of the infraorbital foramen.
Where is the location of the infraorbital foramen?
1/2 the distance & 2.5 cm dorsal to a line connecting the nasomaxillary notch & rostral end of the facial crest.
Which muscle needs to be displaced when giving an infraorbital nerve block?
Levator nasolabialis muscle
Where is the injection given for an infraorbital nerve block?
How much anesthetic is used for a horse?
Perineurally at bony lip of infraorbital foramen using 10 mL of local anesthetic.
How do you locate the infraorbital foramen in cattle?
Rostral to facial tuberosity on a line extending from nasomaxillary notch to 2nd upper premolar
How much local anesthetic is given in cattle?
What are 4 examples of what auriculopalpebral blocks are used for in horses and cattle?
- Examination of eye
- Treatment of eye
- Foreign body removal
- Minor ocular surgery
The blockade of the auriculopalpebral nerve causes what?
Akinesia of eyelids (loss of voluntary movement)
Does an auriculopalpebral block desensitize the eyelids?
No, only paralyzes them.
Where is an auriculopalpebral block given in a horse?
2.5 cm, 20 g needle inserted about 2 cm ventral to most dorsal point of zygomatic arch.
How much local anesthetic is given in an auriculopalpebral block in a horse?
2.5 mL into dorsal border & another 2.5 mL as needle is withdrawn.
Where is an auriculopalpebral block given in cattle?
Along dorsal edge of zygomatic arch. Feel groove about 5-7 cm caudal to notch formed by zygomatic arch & temporal process of malar.
How much local anesthetic is given in an auriculopalpebral block in cattle?
What is the most commonly desensitized nerve in the head of a horse?