Field Anesthesia

Question 1

IV anesthesia can be safely used for up to _______

Answer 1

1 hours; any longer and ideally they would be in hospital under GA with intense monitoring

Question 2

Why do horses have a higher mortality under anesthesia than other species?

Answer 2

Age - Foals <10d, very old patients
Duration of surgery
Drugs for sedation
Inhalants

Question 3

When doing field anesthesia, what is the first factor to consider?

Answer 3

Location

Question 4

T/F: You’ve given a horse your normal dose of xylazine, but it is still quite excited. The next best step is to proceed with anesthesia.

Answer 4

False - never anesthetize an excited horse

Question 5

Fasting protocol for anesthesia

Answer 5

4-6h okay
Some surgeries requires 24-48h

Question 6

What are the three commonly used sedation/premed drugs?

Answer 6

Alpha-2 agonists
Phenothiazines
Opioids

Question 7

What are the two alpha-2 agonists we commonly use?

Answer 7

Xylazine
Detomidine

Question 8

How do you know when a horse is adequately sedated?

Answer 8

“5 point stance”
Head down, droopy eyelids and lips

Question 9

How can xylazine and detomidine be administered?

Answer 9

PO, IM, IV

Question 10

Effects of alpha-2 agonists

Answer 10

Sedation
Muscle relaxation
Analgesia

Question 11

Peak effect for alpha-2 given IV? IM?

Answer 11

3-5 min
15 min

Question 12

Which is more potent - detomidine or xylazine?

Answer 12

Detomidine - but both provide comparable sedation

Question 13

Side effects of alpha-2 agonists

Answer 13

Decreased GI motility
Increased urination d/t transient hyperglycemia (osmotic diuresis)

Question 14

Can detomidine and xylazine be reversed?

Answer 14

Yes - yohimbine, atipamazole, tolazoline

Not common to reverse - often better to allow them to come out on their own

Question 15

How are phenothiazines given?

Answer 15

PO, IV, IM

Question 16

Effects of phenothiazines

Answer 16

Calm, relaxed horse
Potential for hypotension

Question 17

Acepromazine is a _________

Answer 17

Phenothiazine

Question 18

Onset of action and duration of action for acepromazine

Answer 18

Onset: 15-30min (even when given IV)
Duration: 6-10h

Question 19

T/F: Acepromazine provides significant analgesia

Answer 19

False - none!

Question 20

What opiods do we commonly use?

Answer 20

Butorphanol (better analgesia in horses than in cats and dogs)
Morphine (good for painful procedures)
Transdermal fentanyl (not common in sedation protocols)

Question 21

What is the mainstay for induction in horses?

Answer 21

Dissociatives

Question 22

Duration of ketamine-alpha 2 anesthesia

Answer 22

15-20 minutes

Question 23

T/F: it is best to give ketamine and xylazine together to speed up time to induction

Answer 23

False - give your xylazine and allow them to become sedate, then induce with ketamine

Question 24

Ketamine should be given _____

Answer 24

IV

Question 25

What can you add to your induction protocol to smooth induction and increase muscle relaxation?

Answer 25

Diazepam

Question 26

TKD?

Answer 26

Telazol (Tiletamine and zolazepam) + Ketamine + Detomidine

Question 27

T/F: TKD is appropriate for surgical anesthesia

Answer 27

False - mostly just used to quick anesthesia to get them in an ambulance or hoist them on a table to hook up to anesthesia machine, not used for surgical procedures

Question 28

Guaifenesin’s greatest effect is

Answer 28

Muscle relaxation

Question 29

Signs of GG overdose?

Answer 29

Extension of forelimbs Labored breathing Respiratory and cardiac arrest

Question 30

Effect of benzodiazepines in foals <1mo?

Answer 30

Sedation In others, provides additional muscle relaxation

Question 31

How can we prolong xylazine/ketamine anesthesia?

Answer 31

Give another bolus Add GG/ketamine or GKX Detomidine instead of xylazine Give 1/4-1/2 ketamine and Valium

Question 32

What is triple drip?

Answer 32

GKX 1L 5% GG + 500mg + 1-2g ketamine

Question 33

What is the best way to assess plane of anesthesia in horses?

Answer 33

Respiratory rate becomes more rapid and forceful as horse gets lighter If in hospital and are monitoring BP, that will also increase

Question 34

When do most injuries occur?

Answer 34

Induction and recovery Must warn owners of risk of catastrophic injury