General anaesthesia

Question 1

Out of the anaesthesia triad, what do opioids provide?

Answer 1

Analgesia
Unconsciousness
(No muscle relaxation)

Question 2

What effects do opioids have on the GI system?

Answer 2

Slows gut motility

Causes ileus

Question 3

What effect do opioids have on the locomotory system?

Answer 3

May cause locomotory excitement

Question 4

Which is the most likely opioid to cause excitement in horses?

Answer 4

Buprenorphine

Question 5

Which is the best analgesic to assess colic cases?

Answer 5

Xylazine
Short duration (10-20 mins)

Question 6

Which is the longest acting alpha-2 agonist in horses?

Answer 6

Romifidine

60 mins

Question 7

Apart from being the longest acting, what is an advantage of romifidne as a sedative?

Answer 7

Least ataxia

Question 8

Which is the only licensed alpha-2 in horses?

Answer 8

Detomidine

Only licensed IM, but can be used as oral gel

Question 9

Why should acepromazine be avoided in colic?

Answer 9

Vasodilator

Question 10

How long does it take for ACP to act?

Answer 10

45-60 mins

Question 11

What are the side effects of ACP?

Answer 11

Paraphimosis in stallions (erection)

CV side effects

Question 12

What drugs are used to induce horses?

Answer 12

Ketamine and midazolam

Or thiopental/GGE

Question 13

What type of drug is thiopental?

Answer 13

GABA agonist

Barbutiurate

Question 14

How long does ketamine last for?

Answer 14

20 mins

Question 15

What are the side effects of ketamine?

Answer 15

Hypertonicity
Excitement
Myocardial depression
Increased peripheral sympathetic tone

Question 16

Which of the anaesthesia triad does ACP provide?

Answer 16

Muscle relaxation

Unconsciousness (sedation)

Question 17

Which drug used in GAs is most responsible for temperature loss and why?

Answer 17

Isoflurane

Causes systemic vasodilation

Question 18

Can sedatives be used in pregnant mares?

Answer 18

Yes as stress can induce abortion

No licensed sedatives for last trimester

Question 19

What are the 3 H’s?

Answer 19

Hypotension
Hypoventilation
Hypothermia

Question 20

What is the MAC?

Answer 20

Minimum alveolar concentration - concentration at which 50% of patients do not respond to noxious stimuli

Question 21

What are the 4 stages of nociception?

Answer 21

Transduction
Transmission
Modulation
Pereception

Question 22

What local anaesthetic is most commonly used for IV catheter placement?

Answer 22

Mepiviciane

faster onset, less irritant to issues than lidocaine

Question 23

Alpha adrenergic receptors mainly act on which part of the body? What about beta adrenergic receptors?

Answer 23

Alpha = acts on vessels
Beta = acts on heart (beta/beating heart)

Question 24

How does dobutamine work to increase blood pressure? How does it work?

Answer 24

Positive inotrope - increases contractility

Beta adrenergic agonist

Question 25

Where are horses eyes positioned during anaesthesia?

Answer 25

Centrally

Question 26

How is equine anaesthesia depth assessed?

Answer 26

Muscle relaxation (neck)
Eyeball position (central)
Nystagmus (indicates light - except for dissociative drugs e.g. ketamine)
Blood pressure and heart rate

Question 27

What effects do alpha-2s have on blood vessels and blood pressure?

Answer 27

Vasoconstriction

Causes reflex bradycardia to return blood pressure to normal (or slightly below)

Question 28

What are the 3 ways that the body controls pH?

Answer 28

Buffers - bicarbonate
Respiratory system
Kidneys

Question 29

How is the MAP calculated?

Answer 29

DAP + 1/3 (SAP-DAP)

Question 30

What is the most common arrhythmia in horses and how is it treated?

Answer 30

Atrial fibrillation

Quinidine or electroconversion under GA

Question 31

Why do we give midazolam when inducing with ketamine?

Answer 31

To cause muscle relaxation

Ketamine causes muscle rigidity - cannot intubate