Equine anaesthesia workshop

Question 1

How long should you fast a horse for?

Answer 1

Slowing gut down due to starving and sedation => post-op colic risk – leave a horse with a small hay net overnight for them to keep grazing – do not starve but don’t feed loads

Question 2

Is acepromazine licensed for use in horses in the UK?

Answer 2

yerp

Question 3

When would you avoid using acepromazine in horses

Answer 3

Do not administer to breeding stallions - paraphimosis and priapism => willy amputation
Do not use in pregnant mares
Do not use in foals
Do not use in hypovolaemic animals - acepromazine exacerbates vasodilation

Question 4

List the 3 licensed (UK) alpha 2 agonists for horses

Answer 4

xylazine
detomidine
romifidine

Question 5

What induction agent is most used in horses in the UK?

Answer 5

Ketamine

Question 6

Which volatile agents are licensed for use in horses?

Answer 6

Isoflurane

Question 7

Describe the differences between doing an equine GA in a paddock/field compared to doing an equine GA in an equine hospital, e.g. logistics/safety/reasons

Answer 7

Harder to monitor
Require heavy sedation in field - can’t do standing surgery
Less sterile
Can’t intubate/ventilate
Only have equipment you have with you
Smaller team
Only for emergencies
Need to top-up sedation more

Question 8

Owen is a 2-year-old well behaved colt but a little excitable, that the owner would like castrating. The owner would like this procedure done ‘standing’ and is happy to bring Owen to the vet practice for the procedure to be undertaken. Owen weighs 300Kg
* Devise a sedation protocol

Answer 8

Detomidine or romifidine + opioid (butorphanol – enhances sedation) – could use buprenorphine but takes longer to act and costs more
Top-up sedation if procedure is taking longer
Pre-emptive NSAIDs (meloxicam/phenylbutazone)

Question 9

Describe the placement of IV cannulas in horses

Answer 9

o Up the neck – against flow of blood => clots if left in for >24hrs (easier to do)
o Place IV cannulas down the neck in hospitals to prevent clotting
o 12-16 gauge

Question 10

Owen is a 2-year-old well behaved colt but a little excitable, that the owner would like castrating. The owner would like this procedure done ‘standing’ and is happy to bring Owen to the vet practice for the procedure to be undertaken. Owen weighs 300Kg
Describe which local anaesthetic you would like to use, how you would inject it, suggest a suitable dose/volume.

Answer 10

o Lidocaine or mepivacaine
o procaine also licensed (can only give 5mls to a horse – can change colour of fur – tend not to use in horses),
o 10-15ml per testicle
o Volume in body of testicle, some into spermatic cord and some into skin/tunica dartos

Question 11

Dancer is a very valued delightful mare that is intermittently lame on both her hind limbs. She requires a GA for bilateral stifle arthroscopy. She weighs 480Kg.
Devise a suitable anaesthetic protocol, include sedation/premedication, induction of anaesthesia drugs

Answer 11

Acepromazine - calming, help with cannula insertion
Wait 30-45 mins
Alpha-2-agonist (romifidine) + opioid (butorphanol) - top-up until heavily sedated
Ketamine - causes muscle tension (midazolam given to cause muscle relaxation - helps with intubation and procedure)

Question 12

After giving ketamine – how will you ensure a horse becomes recumbent safely. Will you remain in the induction box with her?

Answer 12

Can leave box and let horse go down on its own
Can press horse up against wall and slide down
Can use squeeze door + person with halter to guide down