Equine/Ruminant Anesthesia

Equine eye: Motor block prevents

eyelid closure/blinking

When would we use a motor block for a equine eye?

ophthalmic examination/manipulation

Motor block of the eye does or does not provide analgesia?

does not

Equine eye motor block - what are the landmarks

Bonus points if you can name the alternative route

dorsal aspect of the zygomatic arch

alternative route: caudal to the mandible

Equine eye - name the sensory nerves

A - Supraorbital nerve

B - Lacrimal nerve

C - Infratrochlear nerve

D - Zygomatic nerve

Equine eye: Supraorbital nerve affects the

majority of the upper eyelid

Equine eye: Lacrimal nerve nerve affects the

lateral upper eyelid

Equine eye: infratrochlear nerve nerve affects the

medial upper eyelid/canthus

Equine eye: Zygomatic nerve nerve affects the

lateral/lower orbital region

Equine eye: when would we use a sensory block vs a motor block?

Sensory - eyelid procedures combined with deeper orbital analgesia for enucleation

Motor - ophthalmic examination/manipulation

Equine eye: when trying to block the sensory supraorbital nerve what landmark would we look for?

supraorbital foramen

What does perineurial block mean?

block the area surrounding the nerve and stop pain signals

Ruminant eye: You would use a auriculopalpebral block for what procedure?

Examination of the eye

Ruminant eye: When giving an auriculopalpebral block we are blocking what nerve?

auriculopalpebral branch of the facial nerve

Ruminant eye: What does an auriculopalpebral block accomplish?

stops blinking for the exam

Ruminant eye: An auriculopalpebral block does or does not provide analgesia?

does not

Ruminant eye: 4 point orbital block , blocks what nerves

sensory and motor nerves within the orbit

Ruminant eye: for a 4 point orbital block what landmarks are we looking for

4 injection sites around the orbital margin

Ruminant eye: What procedure would a 4 point block be needed?

eyelid surgery (mass removal/lac repair)

Both: Retrobulbar block is used for what procedure

enucleation

Both: Retrobulbar block affects what nerves?

Orbital sensory and motor nerves within the orbit, providing ocular analgesia/anethesia and reduced globe movement

Both: The retrobulbar block does/does not have analgesia properties?

Does

Both: What landmarks are we looking for a retrobulbar block?

Space behind the globe - identify the orbital rim and lateral canthus. The needle passes alongside the globe into the retrobulbar space behind the eye.

Equine dental: For a infraorbital nerve block what landmark are we looking for?

infraorbital foramen

Equine dental: For a infraorbital nerve block what nerve are we blocking?

Infraorbital nerve

Equine dental: For a infraorbital nerve block what body part(s) are affected?

upper lip and nostril

Equine dental: For a deep infraorbital nerve block what body part(s) are affected?

maxillary teeth/nasal structures

Equine dental: Inferior alveolar nerve block, what landmarks are we looking for?

Mandibular foramen on the medial aspect of the mandible

Equine dental: Inferior alveolar nerve block, what nerve are we blocking?

Inferior alveolar nerve, branch of the mandibular division of the trigeminal nerve

Equine dental: Inferior alveolar nerve block what is the desired effect?

Anesthesia of the ipsilateral mandible and mandibular teeth

Equine dental: Maxillary nerve block, what are the landmarks we’re looking for?

Maxillary foramen, deep to the zygomatic arch/orbital fossa

Equine dental: Maxillary nerve block, what nerves are we blocking?

Maxillary nerve, branch of the trigeminal nerve

Equine dental: Maxillary nerve block, what effects are we hoping for?

Anaesthesia of the ipsilateral maxilla, maxillary teeth and associated sinus/nasal structures

Intratesticular block use for what procedure(s)

castrations

Intratesticular block effect

diffuses into the spermatic cord and provides local anesthesia

Intratesticular block benefits

Reduces general anesthetic requirements and supports multimodal analgesia

Ruminant (Cattle) dehorning: what nerve are we blocking?

Corneal branch of the zygomaticotemporal nerve

Ruminant (Goat) dehorning: what nerves are we blocking?

Cornural branch of zygomaticotemporal nerve

Cornual branch of the infratrochlear nerve

Bier block involves

distal limb/foot

Bier block technique

local anesthetic injected to a distal vein

Bier block effect

anesthetizes tissues distal to the torniquet

Bier block benefit

provides dense regional anesthesia with a relatively small local anesthetic dose

Ruminant flank laparotomy line block : Landmark?

Planned incision line

Ruminant flank laparotomy line block: Technique

Local anesthetic infiltrated through the skin, SQ tissue and muscle layers

Ruminant flank laparotomy line block: effect

desensitizes the tissues along the incision

Ruminant flank laparotomy inverted L block: blocks what nerves?

Dorsal and ventral branches of T13, L1 and L2

Ruminant flank laparotomy inverted L block: landmarks

Caudal to the last rib

ventral to the lumbar transverse processes

Ruminant flank laparotomy inverted L block: technique?

Local anesthetic infiltrated in an inverted L pattern away from the incision

Ruminant flank laparotomy inverted L block: effect?

Desensitizes the flank by blocking the nerves before they reach the incision area

Ruminant flank laparotomy: proximal paravertebral block - what nerves are we blocking?

Dorsal and ventral branches of T13, L1 and L2 (at origin)

Ruminant flank laparotomy proximal paravertebral block: landmarks

Close to the spine, near the intervertebral foramina where the T13, L1 and L2 spinal nerves emerge

Ruminant flank laparotomy proximal paravertebral block: Technique

Local anesthetic deposited close to the nerves as they emerge from the intervertebral foramina

Ruminant flank laparotomy proximal paravertebral block: effects

desensitizes a large area of the flank

Ruminant flank laparotomy proximal paravertebral block: How do we know the block is working?

Scoliosis toward the blocked side - increased skin temp - reduced/absent response to pinprick

Ruminant flank laparotomy distal paravertebral block: Nerves

T13, L1 and L2

Ruminant flank laparotomy distal paravertebral block: Landmarks

Transverse processes of L1, L2 and L4

Ruminant flank laparotomy distal paravertebral block: Technique

Local anesthetic deposited dorsal and ventral to the transverse processes

anesthesia of the udder paravertebral block: nerves

lumbar spinal nerves L1-3

anesthesia of the udder pudendal block: nerves

Pudendal nerve, including its mammary branch

anesthesia of the udder pudendal block: Landmark

Lesser scrosciati foramen, located by rectal palpation

anesthesia of the udder pudendal block: effect

desensitizes the caudal aspect of the udder and teats

Anesthesia of the teats: uses

teat lac, polyp removal, other minor procedures

Anesthesia of the teats: Ring block

local anesthetic infiltrated circumferentially around the teat

Anesthesia of the teats: Inverted V block

local anesthetic infiltrated in a V shaped pattern proximal to the surgical site

Anesthesia of the teats: Tear cistern infusion

local anesthetic placed into the teat cistern

Anesthesia of the teats: Tear cistern infusion effect

anesthesia of the mucous membrane

Anesthesia of the teats: IV regional anesthesia

Tourniquet applied then local anesthetic injected into a distal vein

Equine epidural: indications

tail and perineal procedures

rectal procedures

vulva/vaginal procedures

obstetric manipulations

caudal urethral/bladder procedures

hind limb analgesia with appropriate epidural analgesic drugs

What is the main concern with equine epidurals?

Loss of control of the hind limbs

Equine epidural: Landmark

Co1-Co2 space

Equine epidural: Confirmation that block was done correctly

loss of resistance/hanging drop technique

Equine epidural: Goal

maintain standing motor function

Equine epidural drugs used (3)

Lidocaine 2%

Alpha 2 agonist

Morphine

Lidocaine 2% has anesthesia/analgesia/both properties

anesthesia

Alpha 2 agonists have anesthesia/analgesia/both properties

both

Morphine has anesthesia/analgesia/both properties

long lasting analgesia

long term equine epidural catheter entry site

Co1-Co2 space

long term equine epidural catheter - why?

allows for repeated doses of analgesia is needed over several days

hind limb pain

long term equine epidural catheter - what drugs can be given alone or in combination?

Morphine and Alpha 2 agonist

Ruminant caudal epidural : structures blocked

caudal spinal nerve roots

Ruminant caudal epidural : effects

providing analgesia to the tail and perineal region

Ruminant caudal epidural : Landmarks

S5-Co1 or Co1-Co2 interspace

Ruminant caudal epidural : main use

obstetric manipulations and procedures involving the tail, perineum, anus rectum, vulva or vagina

Ruminant lumbosacral epidural: structures blocked

spinal nerve roots supplying the caudal body and hindlimb

Ruminant lumbosacral epidural: landmarks

L6-S1 interspace

Ruminant lumbosacral epidural: main use

more extensive caudal procedures in small ruminants, immature cattle, camelids and pigs

Ruminant lumbosacral epidural: key consideration

hindlimb motor block may occur