Large Animal Anesthesia

Question 1

What are the 3 basic principles of large animal anesthesia?

Answer 1

1. Animals of different species respond differently to anesthestics
2. Large animals with lower metabolic rates require a lower dosage of anesthetics
3. Handling & restraint of anesthetized large animals is critically important in equine anesthesia

Question 2

What form of anesthesia is most common in equine anesthesia?

Answer 2

Sedation & standing chemical restraint is the most common form of anesthesia

Question 3

When is sedation & standing chemical restraint most commonly used?

Answer 3

Diagnostic & minor surgical procedures

Question 4

Why is sedation & standing chemical restraint used?

Answer 4

To prevent injuries associated with recumbency

Question 5

What are common chemical restraints used in large animals?

Answer 5

1. Xylazine or Detomidine are used alone
2. Xylazine + Butophanol + Acepromazine are used in combination
3. Detomidine + Butorphanol are used in combination

Question 6

When is intravenous general anesthesia used?

Answer 6

For short surgical or diagnostic procedures

Question 7

Intravenous general anesthesia is also called?

Answer 7

Field Anesthesia

Question 8

Intravenous general anesthesia or field anesthesia requirements?

Answer 8

1. Induce a light plane of general anesthesia with injectable anesthestics
2. Area must be free of any visible hazards
3. Understand the risk of induction & recovery

Question 9

What anesthetic agents are used for intravenous or field anesthesia?

Answer 9

◦ Xylazine + Ketamine
◦ Xylazine + Ketamine +Guaifenesin (triple drip)
◦ Xylazine + Diazepam + Ketamine
◦ Xylazine + Propofol + Ketamine

Question 10

What are the key principles during inhalant anesthesia in large animals?

Answer 10

◦ Use a large animal gas anesthesia machine if patient > 150 kg
◦ Rinse mouth prior to induction
◦ Use protective padding under horse

Question 11

What is the biggest concern when performing gas anesthesia on large animals specifically horses?

Answer 11

Having them in lateral recumbency - Horses or other large animal should have heavy pads underneath them during anesthesia because if they don’t have it their muscles will have a lot of pressure for a long period of time which can cause nerve damage and then they aren’t able to stand afterwards.
• They also get low blood pressure under anesthesia so when they have no padding minimal blood flow goes to the muscles

Question 12

Lateral recumbency key factors during inhalant anesthesia for large animals are?

Answer 12

‣ Dependent forelimb pulled forward
‣ Pads used to keep upper and lower hindlegs parallel
‣ Post-Anesthetic Myopathy
• Horses or other large animal should have heavy pads underneath them during anesthesia because if they don’t have it their muscles will have a lot of pressure for a long period of time which can cause nerve damage and then they aren’t able to stand afterwards.
• They also get low blood pressure under anesthesia so when they have no padding minimal blood flow goes to the muscles

Question 13

Post-Anesthetic Myopathy

Answer 13

Horses or other large animal should have heavy pads underneath them during anesthesia because if they don’t have it their muscles will have a lot of pressure for a long period of time which can cause nerve damage and then they aren’t able to stand afterwards.

Question 14

What type of catheter is placed?

Answer 14

Place an arterial catheter in a peripheral artery to measure the blood pressure in a horse like under the bottom jaw, or the leg

Question 15

Why is an arterial catheter required during intravenous general or field anesthesia

Answer 15

Hypoxemia and hypotension is common during anesthesia especially in horses therefore an arterial catheter must be placed to monitor

Question 16

Where do you place a catheter at in a horse?

Answer 16

Under the bottom jaw or the leg

Question 17

During a recovery from anesthesia where should a stall be placed?

Answer 17

In a padded stall so it doesn’t hurt itself