Local Anesthesia Flashcards
(22 cards)
Onset and duration of lidocaine
Onset: 3-5 minutes
Duration: 1-2h
T/F: Lidocaine has a longer duration than bupivacaine
False - bupivacaine is 4-6h, lidocaine is 1-2h
__________ is the most important motor block when performing an ocular exam
Auriculopalpebral
When is it helpful to add in sensory blocks to the eye?
Minor surgical eyelid procedures so they can’t feel us suturing them up
Why is it important to use a short acting drug (lidocaine) when blocking motor innervation to the eyelid?
Need them to blind to keep tear film - don’t want anesthetized for too long so wouldn’t use something like bupivacaine
What block will block most sensory innervation to the upper eyelid?
Supraorbital - inject in and over supraorbital foramen
Aside from the supraorbital nerve, what other nerves can be blocked to inhibit sensory innervation?
Lacrimal - temporal canthus, 25% upper lid
Infratrochlear - nasal canthus
Zygomaticofacial - lower lid
Infraorbital I provides analgesia to
Upper lip and nose
Infraorbital II provides anesthesia to
Teeth to 1st molar, maxillary sinus, roof of nasal cavity, skin to medial canthus
Done by actually threading needle into infraorbital foramen (not well tolerated by standing horses)
Blocking maxillary nerve provides anesthesia to
All upper teeth, sinuses, and nasal cavity
Mandibular block will anesthetize
All mandibular structures, lateral canthus, mandibular cheek teeth
You want to block just the lower incisors for a dental procedure. What block can you do?
Mental II
Name some indications for an epidural
- Procedures involving rectum, vagina, perineum, urethra, and bladder
- Obstetric manipulations
- Analgesia of stifles and hocks
- Intraoperative
When might an epidural be contraindicated?
- Infection @ puncture site
- Sepsis
- Uncorrected hypovolemia, anticoagulation
- Anatomic abnormalities
Describe the location of the epidural space
Within spinal canal outside the visceral layer of the dura matter
Not the subarachnoid space
T/F: lumbosacral epidurals are more commonly used in horses than caudal
False - Special equipment and very strict aseptic technique required for LS. Caudal is more common b/c it is simpler and doesn’t require any special equipment
Define the landmarks for LS subarachnoid
1-2cm caudal to a line drawn from the cranial edge of tuber sacral and dorsal midline
Define landmarks for caudal epidural
Palpate Co1-Co2 as the first midline depression caudal to the sacrum
First movable coccygeal articulation when the tail is raised and lowered
When might you consider an epidural catheter?
Repeat dosing
Very painful conditions that require continuous epidural analgesia
What can you combine with local anesthesia to prolong analgesia?
Alpha-2 agonists
Biggest consideration is that you will see systemic effects
Why might opioids be used in an epidural?
Inhibition of pain transmission
Minimal motor nerve blockade, minimal dose requirements, few side effects
T/F: You can use both PF or regular morphine in horses.
True - PF is better for repeated administration, but regular morphine is good for one time use
PF is more expensive and requires a larger volume
